Oligonucleotide compositions and methods thereof

Abstract

Among other things, the present disclosure provides oligonucleotide compositions and methods thereof. In some embodiments, oligonucleotides comprise various chemical modifications of sugars, nucleobases, and / or internucleotidic linkages and patterns thereof and are useful for exon skipping. In some embodiments, the present disclosure provides technologies useful for skipping exon 45 of dystrophin (DMD) transcripts. In some embodiments, the present disclosure provides technologies useful for modulating DMD transcript splicing. In some embodiments, the present disclosure provides methods for preventing or treating conditions, disorders or diseases including Duchenne muscular dystrophy.

Description

OLIGONUCLEOTIDE COMPOSITIONS AND METHODS THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to International Application No. PCT / US2024 / 049139, filed September 27, 2024, the entirety of which is incorporated herein by reference. BACKGROUND

[0002] Oligonucleotides are useful in various applications, e.g., therapeutic, diagnostic, and / or research applications. For example, oligonucleotides targeting various genes can be useful for treatment of conditions, disorders or diseases related to such target genes. SUMMARY

[0003] Among other things, the present disclosure encompasses the recognition that structural elements of oligonucleotides, such as base sequence, chemical modifications (e.g., modifications of sugar, base, and / or internucleotidic linkages, and patterns thereof), and / or stereochemistry (e.g., stereochemistry of backbone chiral centers (chiral internucleotidic linkages), and / or patterns thereof), can have a significant impact on oligonucleotide properties, e.g., exon skipping (e.g., of exon 45 of DMD), toxicities, stability, protein binding characteristics, etc. In some embodiments, the present disclosure provides oligonucleotides that, among other things, have certain numbers of PN linkages at certain locations. Such PN linkages, in combination with other structure features (e.g., 2’-F modified sugars, 2’-OMe modified sugars, phosphorothioate internucleotidic linkages, natural phosphate linkages, linkage phosphorus stereochemistry, etc.) of such oligonucleotides, can provide useful therapeutic profiles, such as pharmacokinetic and pharmacodynamic profiles including delivery, distribution, stability, exon skipping efficiency, toxicity, etc., for such oligonucleotides to be utilized for treating conditions, disorders or diseases including DMD.

[0004] In some embodiments, the present disclosure provides an oligonucleotide or an oligonucleotide composition capable of mediating skipping of an exon, e.g., exon 45, of the DMD gene and useful for treating muscular dystrophy. In some embodiments, an oligonucleotide or an oligonucleotide composition is useful for treatment of muscular dystrophy. In some embodiments, an oligonucleotide is an oligonucleotide disclosed herein (e.g., in Table 1, e.g., in Table 1A, Table 1B, Table 1C). In some embodiments, an oligonucleotide composition is a composition comprising an oligonucleotide disclosed herein (e.g., in Table 1, e.g., in Table 1A, Table 1B, Table 1C). In some embodiments, an oligonucleotide composition is a chirally controlled oligonucleotide composition comprising an oligonucleotide disclosed herein (e.g., in Table 1, e.g., in Table 1A, Table 1B, Table 1C).

[0005] Among other things, the present disclosure provides oligonucleotides and compositions thereof that have demonstrated various advantages and improvements. For example, as demonstrated herein, certainoligonucleotides and compositions have demonstrated not only high exon skipping levels, but also high levels of stability and low toxicity when assessed in a variety of assays.

[0006] In some embodiments, the present disclosure provides an oligonucleotide, wherein the base sequence of the oligonucleotide comprises 15 or more contiguous nucleobases, e.g., 20 contiguous nucleobases, of a complement of a DMD transcript, wherein the oligonucleotide comprises 4 or more PN (phosphoryl guanidine, e.g., n001) internucleotidic linkages, e.g., 4 PN internucleotidic linkages, and wherein the oligonucleotide comprises a PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside and / or a PN internucleotidic linkage between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside, e.g., the oligonucleotide comprises a PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside, and it does not comprise a PN internucleotidic linkage between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside. In some embodiments, the PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside is in the Rp configuration. In some embodiments, all of the PN internucleotidic linkages are in the Rp configuration. In some embodiments, the 5’ terminal (+1) nucleoside, and / or the 3’ terminal (N) nucleoside, of the oligonucleotide comprises a modified sugar moiety, e.g., a 2’-OMe modification, e.g., the 5’ terminal (+1) nucleoside comprises a 2’-OMe modification, and the 3’ terminal (N) nucleoside does not comprise a 2’-OMe modification. In some embodiments, the oligonucleotide comprises a PN internucleotidic linkage between the +3 nucleoside and the +4 nucleoside, a PN internucleotidic linkage between the +6 nucleoside and the +7 nucleoside, and / or a PN internucleotidic linkage between the +17 nucleoside and the +18 nucleoside. In some embodiments, the PN internucleotidic linkage between the +3 nucleoside and the +4 nucleoside, the PN internucleotidic linkage between the +6 nucleoside and the +7 nucleoside, and / or the PN internucleotidic linkage between the +17 nucleoside and the +18 nucleoside, are in the Rp configuration. In some embodiments, the oligonucleotide comprises a PS (e.g., a phosphorothioate) linkage between the +2 nucleoside and the +3 nucleoside, a PS linkage between the +4 nucleoside and the +5 nucleoside, a PS linkage between the +5 nucleoside and the +6 nucleoside, a PS linkage between the +8 nucleoside and the +9 nucleoside, a PS linkage between the +9 nucleoside and the +10 nucleoside, a PS linkage between the +10 nucleoside and the +11 nucleoside, a PS linkage between the +11 nucleoside and the +12 nucleoside, a PS linkage between the +13 nucleoside and the +14 nucleoside, a PS linkage between the +14 nucleoside and the +15 nucleoside, a PS linkage between the +15 nucleoside and the +16 nucleoside, a PS linkage between the +16 nucleoside and the +17 nucleoside, and a PS linkage between the +18 nucleoside and the +19 nucleoside, each independently in, e.g., the Sp configuration. In some embodiments, the oligonucleotide comprises a PS linkage in, e.g., the Sp configuration, or a PN linkage in, e.g., the Rp configuration, between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside. In some embodiments, the sugar moiety of the +7 nucleoside comprises a 2’-OMe modification, the sugar moiety of the +10 nucleoside comprises a 2’-OMe modification, the sugar moiety of the +12 nucleoside comprises a 2’-OMe modification, and / or the sugar moiety of the +13 nucleoside comprises a 2’-OMe modification. Insome embodiments, the sugar moiety of the 3’ terminal (N) nucleoside, comprises a 2’-OMe modification. In some embodiments, the sugar moiety of the 3’ terminal (N) nucleoside, comprises a 2’-F modification.

[0007] In some embodiments, the present disclosure provides an oligonucleotide, wherein the base sequence of the oligonucleotide comprises 15 or more contiguous nucleobases, e.g., 20 contiguous nucleobases, of a complement of a DMD transcript, wherein the oligonucleotide comprises a PN (e.g., a phosphoryl guanidine, e.g., a n001) internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside in the Rp configuration, a PN internucleotidic linkage between the +3 nucleoside and the +4 nucleoside in the Rp configuration, a PN internucleotidic linkage between the +6 nucleoside and the +7 nucleoside in the Rp configuration, and a PN internucleotidic linkage between the +17 nucleoside and the +18 nucleoside in the Rp configuration, and wherein the sugar moiety of the 5’ terminal (+1) nucleoside comprises a 2’-OMe modification. In some embodiments, the present disclosure provides an oligonucleotide, wherein the base sequence of the oligonucleotide comprises 15 or more contiguous nucleobases, e.g., 20 contiguous nucleobases, of a complement of a DMD transcript, wherein the oligonucleotide comprises a PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside in the Rp configuration, a PN internucleotidic linkage between the +3 nucleoside and the +4 nucleoside in the Rp configuration, a PN internucleotidic linkage between the +6 nucleoside and the +7 nucleoside in the Rp configuration, and a PN internucleotidic linkage between the +17 nucleoside and the +18 nucleoside in the Rp configuration, and wherein the sugar moiety of the 5’ terminal (+1) nucleoside comprises a 2’-F modification. In some embodiments, the oligonucleotide comprises a PS (e.g., a phosphorothioate) linkage between the +2 nucleoside and the +3 nucleoside in the Sp configuration, a PS linkage between the +4 nucleoside and the +5 nucleoside in the Sp configuration, a PS linkage between the +5 nucleoside and the +6 nucleoside in the Sp configuration, a PS linkage between the +8 nucleoside and the +9 nucleoside in the Sp configuration, a PS linkage between the +9 nucleoside and the +10 nucleoside in the Sp configuration, a PS linkage between the +10 nucleoside and the +11 nucleoside in the Sp configuration, a PS linkage between the +11 nucleoside and the +12 nucleoside in the Sp configuration, a PS linkage between the +13 nucleoside and the +14 nucleoside in the Sp configuration, a PS linkage between the +14 nucleoside and the +15 nucleoside in the Sp configuration, a PS linkage between the +15 nucleoside and the +16 nucleoside in the Sp configuration, a PS linkage between the +16 nucleoside and the +17 nucleoside in the Sp configuration, and a PS linkage between the +18 nucleoside and the +19 nucleoside in the Sp configuration. In some embodiments, the oligonucleotide comprises a PS linkage between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside in the Sp configuration. In some embodiments, the oligonucleotide comprises a PN linkage between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside in the Rp configuration. In some embodiments, the sugar moiety of the +7 nucleoside comprises a 2’-OMe modification, the sugar moiety of the +10 nucleoside comprises a 2’-OMe modification, the sugar moiety of the +12 nucleoside, comprises a 2’-OMe modification, and the sugar moiety of the +13 nucleoside comprises a 2’- OMe modification. In some embodiments, the sugar moiety of the 3’ terminal (N) nucleoside, comprises a 2’-OMe modification. In some embodiments, the sugar moiety of the 3’ terminal (N) nucleoside, comprises a 2’- F modification.

[0008] In some embodiments, an oligonucleotide is selected from [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[ Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(A)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[ Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001].m(C)p.[fl2 r](G)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(C)p.m(C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[Ssp].[fl2r](A)[ Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C), [fl2r](U)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](C)[n001].m(A)p.[fl2 r](A)[Ssp].[fl2r](C)[Ssp].m(A)[Ssp].[fl2r](G)[Ssp].m(U)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[ Ssp].[fl2r](C)[n001].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](U), [fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](A)[n001].m(C)p.[fl2 r](A)[Ssp].[fl2r](A)[Ssp].m(C)[Ssp].[fl2r](A)[Ssp].m(G)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[ Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](G)[Ssp].[fl2r](C), [fl2r](G)[n001].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(A)p.[f l2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U )[Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](U)[n001].[fl2r](U)[Ssp].[fl2r](C)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](A)[n001].m(C)p.[fl 2r](A)[Ssp].[fl2r](A)[Ssp].m(C)[Ssp].[fl2r](A)[Ssp].m(G)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](G) [Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](G)[Ssp].[fl2r](C), [fl2r](U)[n001].[fl2r](C)[Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](C)[n001].m(A)p.[fl 2r](A)[Ssp].[fl2r](C)[Ssp].m(A)[Ssp].[fl2r](G)[Ssp].m(U)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C) [Ssp].[fl2r](C)[n001].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](U), [fl2r](C)[n001].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl 2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C) [Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[n001].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001].m(C)p.[fl 2r](G)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(C)p.m(C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[Ssp].[fl2r](A) [Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(A)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[ Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[n001].[fl2r](G),[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](A)[n001].m(C)p.[fl2 r](A)[Ssp].[fl2r](A)[Ssp].m(C)[Ssp].[fl2r](A)[Ssp].m(G)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[ Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](G)[n001].[fl2r](C), [fl2r](U)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](C)[n001].m(A)p.[fl2 r](A)[Ssp].[fl2r](C)[Ssp].m(A)[Ssp].[fl2r](G)[Ssp].m(U)p.m(U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[ Ssp].[fl2r](C)[n001].[fl2r](G)[Ssp].[fl2r](C)[n001].[fl2r](U), [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[ Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](U)[n001].[fl2r](G), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001].m(C)p.[fl2 r](G)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(C)p.m(C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[Ssp].[fl2r](A)[ Ssp].[fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](C)[n001].[fl2r](C), [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl2 r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[ Ssp].[fl2r](G)[n001].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), [fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].[fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(C)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(U)[Ssp].[fl2r](C)[Ssp].m(C)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](G)[Ssp].[fl2r](A)[ Ssp].[fl2r](G)[n001].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C), [fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(U)p.[fl2 r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[ Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](U)[n001].[fl2r](G)[Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl 2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U) [Ssp].[fl2r](G)[n001].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), [fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](A)[n001].[fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(C)p.[fl 2r](C)[Ssp].[fl2r](A)[Ssp].m(U)[Ssp].[fl2r](C)[Ssp].m(C)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](G)[Ssp].[fl2r](A) [Ssp].[fl2r](G)[n001].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C), [fl2r](A)[n001].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(U)p.[fl 2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U) [Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(A)p.[fl2 r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[ Ssp].[fl2r](G)[n001].[fl2r](G)[Ssp].[fl2r](A)[n001].[fl2r](G), [fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].[fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].m(C)p.[fl2 r](C)[Ssp].[fl2r](A)[Ssp].m(U)[Ssp].[fl2r](C)[Ssp].m(C)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](G)[Ssp].[fl2r](A)[ Ssp].[fl2r](G)[n001].[fl2r](U)[Ssp].[fl2r](U)[n001].[fl2r](C),[fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001].m(U)p.[fl2 r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[ Ssp].[fl2r](C)[n001].[fl2r](C)[Ssp].[fl2r](U)[n001].[fl2r](G), [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2 r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G),m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2 r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), and [fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; [n001] representsepresents [n001] wherein the phosphorus is of the Rp configuration.

[0009] In some embodiments, as demonstrated herein, provided technologies (e.g., oligonucleotides, compositions, methods, etc.) are particularly useful for reducing levels of a mutant mRNA (e.g., a DMD transcript comprising a deleterious mutation) and / or proteins encoded thereby, and increasing levels of repairedmRNA (e.g., a DMD transcript in which exon 45 is skipped to delete, correct or compensate for a deleterious mutation) and / or proteins encoded thereby.

[0010] In some embodiments, provided technologies are particularly useful for modulating splicing of DMD transcripts, e.g., to increase levels of desired splicing products and / or to reduce levels of undesired splicing products. In some embodiments, provided technologies are particularly useful for reducing levels of DMD transcripts (e.g., mutant DMD transcripts), e.g., pre-mRNA, RNA, etc., and in many instances, reducing levels of products arising from or encoded by such DMD transcripts such as mRNA, polypeptides, proteins, etc. In some embodiments, a pre-mRNA or mRNA or RNA is transported from one cellular compartment (e.g., nucleus, cytoplasm, etc.) to another, and / or has been modified by one or more enzyme.

[0011] For example, in some embodiments, a dystrophin gene can comprise an exon comprising one or more mutations associated with muscular dystrophy (including but not limited to Duchenne (Duchenne’s) muscular dystrophy (DMD) and Becker (Becker’s) muscular dystrophy (BMD)). In some embodiments, a disease-associated exon comprises a mutation (e.g., a missense mutation, a frameshift mutation, a nonsense mutation, a premature stop codon, etc.) in an exon. In some embodiments, the present disclosure provides compositions and methods for effectively skipping a disease-associated dystrophin exon, while maintaining or restoring the reading frame so that a shorter (e.g., truncated, e.g., internally truncated) but partially functional dystrophin (e.g., a variant) can be produced.

[0012] In some embodiments, the present disclosure provides an oligonucleotide, wherein the base sequence of the oligonucleotide comprises 10 or more contiguous nucleobases of a complement of a DMD transcript and the oligonucleotide comprises 3 or more PN internucleotidic linkages. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of a complement of a DMD transcript. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases of a complement of a DMD transcript. In some embodiments, a base sequence of an oligonucleotide is the same as an equal length portion in a complement of a DMD transcript. In some embodiments, the present disclosure provides an oligonucleotide, wherein the base sequence of the oligonucleotide comprises 10 or more contiguous nucleobases that are complementary to an equal length portion in a DMD transcript and the oligonucleotide comprises 3 or more PN internucleotidic linkages. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases that are complementary to an equal length portion in a DMD transcript. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases that are complementary to an equal length portion in a DMD transcript. In some embodiments, a base sequence of the oligonucleotide is complementary to the base sequence of an equal length portion in a DMD transcript. In some embodiments, the present disclosure provides an oligonucleotide, wherein the oligonucleotide can hybridize to an equal length portion in a DMD transcript and the oligonucleotide comprises 3 or more PN internucleotidic linkages. In some embodiments, a DMD transcript is a DMD mRNA. In some embodiments, a DMD transcript or a wild-type version thereof encodes dystrophin. In some embodiments, a DMD transcript comprises a mutation that isamenable to exon 45 skipping.

[0013] In some embodiments, each nucleobase of an oligonucleotide is independently an optionally substituted nucleobase selected from A, T, C, G and U, or an optionally substituted tautomer of a nucleobase selected from A, T, C, G and U. In some embodiments, each nucleobase of an oligonucleotide is independently A, T, C, 5mC, G or U. In some embodiments, length of an oligonucleotide is 20 or more nucleobases. In some embodiments, length of an oligonucleotide is 20 nucleobases.

[0014] In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more Rp PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more Rp PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3 or more Rp PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more Rp PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more Rp PN internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more Rp PN internucleotidic linkages. In some embodiments, each PN internucleotidic linkage is a Rp PN internucleotidic linkage. In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more phosphoryl guanidine internucleotidic linkages. In some embodiments, each PN internucleotidic linkage is a phosphoryl guanidine internucleotidic linkage. In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more Rp phosphoryl guanidine internucleotidic linkages. In some embodiments, each phosphoryl guanidine internucleotidic linkage is a Rp phosphoryl guanidine internucleotidic linkage. In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises3 or more n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more n001 internucleotidic linkages. In some embodiments, each phosphoryl guanidine internucleotidic linkage is a n001 internucleotidic linkage. In some embodiments, an oligonucleotide comprises 3, 4, 5, 6 or more Rp n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4, 5, 6 or more Rp n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 3 or more Rp n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 4 or more Rp n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 5 or more Rp n001 internucleotidic linkages. In some embodiments, an oligonucleotide comprises 6 or more Rp n001 internucleotidic linkages. In some embodiments, each n001 internucleotidic linkage is a Rp n001 internucleotidic linkage.

[0015] In some embodiments, an internucleotidic linkage between the first and the second nucleosides, the third and the fourth nucleosides, the sixth and the seventh nucleosides, the 17th and the 18th nucleosides, and / or the last two nucleosides (unless otherwise noted, 5’ to 3’ direction) of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the first and the second nucleosides, the third and the fourth nucleosides, the sixth and the seventh nucleosides, and the 17th and the 18th nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the third and the fourth nucleosides, the sixth and the seventh nucleosides, the 17th and the 18th nucleosides, and the last two nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the first and the second nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the third and the fourth nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the sixth and the seventh nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the 17th and the 18th nucleosides of an oligonucleotide is a PN linkage. In some embodiments, an internucleotidic linkage between the last two nucleosides of an oligonucleotide is a PN linkage.

[0016] In some embodiments, an oligonucleotide comprises a PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more PS internucleotidic linkages. In some embodiments, an oligonucleotide comprises a PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises a Sp PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more Sp PS internucleotidic linkages. In some embodiments, each PS internucleotidic linkage is Sp. In some embodiments, each PS internucleotidic linkage is independently a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more phosphorothioate internucleotidic linkages. In some embodiments, an oligonucleotide comprises a Sp phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more Spphosphorothioate internucleotidic linkages. In some embodiments, each phosphorothioate internucleotidic linkage is independently Sp.

[0017] In some embodiments, an internucleotidic linkage between the first and the second nucleosides, the second and the third nucleosides, the fourth and the fifth nucleosides, the fifth and the sixth nucleosides, the eighth and the ninth nucleosides, the ninth and the tenth nucleosides, the 10th and the 11th nucleosides, the 11th and the 12th nucleosides, the 13th and the 14th nucleosides, the 14th and the 15th nucleosides, the 15th and the 16th nucleosides, the 16th and the 17th nucleosides, the 18th and the 19th nucleosides, and / or the last two nucleotides (unless otherwise noted, 5’ to 3’ direction) of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the second and the third nucleosides, the fourth and the fifth nucleosides, the fifth and the sixth nucleosides, the eighth and the ninth nucleosides, the ninth and the tenth nucleosides, the 10th and the 11th nucleosides, the 11th and the 12th nucleosides, the 13th and the 14th nucleosides, the 14th and the 15th nucleosides, the 15th and the 16th nucleosides, the 16th and the 17th nucleosides, the 18th and the 19th nucleosides, and the last two nucleotides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the first and the second nucleosides, the second and the third nucleosides, the fourth and the fifth nucleosides, the fifth and the sixth nucleosides, the eighth and the ninth nucleosides, the ninth and the tenth nucleosides, the 10th and the 11th nucleosides, the 11th and the 12th nucleosides, the 13th and the 14th nucleosides, the 14th and the 15th nucleosides, the 15th and the 16th nucleosides, the 16th and the 17th nucleosides, and the 18th and the 19th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the first and the second nucleosides of an oligonucleotide, if it is not a PN linkage, is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the second and the third nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the fourth and the fifth nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the fifth and the sixth nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the eighth and the ninth nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the ninth and the tenth nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 10th and the 11th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 11th and the 12th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 13th and the 14th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 14th and the 15th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 15th and the 16th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 16th and the 17th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidiclinkage between the 18th and the 19th nucleosides of an oligonucleotide is a PS internucleotidic linkage. In some embodiments, an internucleotidic linkage between the last two nucleosides of an oligonucleotide, if it is not a PN linkage, is a PS internucleotidic linkage.

[0018] In some embodiments, an oligonucleotide comprises a PO internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5 or more PO internucleotidic linkages. In some embodiments, each PO internucleotidic linkage is independently a natural phosphate linkage. In some embodiments, an oligonucleotide comprises a natural phosphate internucleotidic linkage. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5 or more natural phosphate internucleotidic linkages. In some embodiments, an internucleotidic linkage between the seventh and the eighth nucleoside of an oligonucleotide is a PO internucleotidic linkage. In some embodiments, an internucleotidic linkage between the 12th and the 13th nucleoside of an oligonucleotide is a PO internucleotidic linkage.

[0019] In some embodiments, an oligonucleotide comprises a sugar modification. In some embodiments, an oligonucleotide comprises a 2’-modified sugar. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more 2’-modified sugars. In some embodiments, an oligonucleotide comprises a 2’-F modified sugar. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more 2’-F modified sugars. In some embodiments, sugar of nucleosides 1, 2, 3, 4, 5, 6, 8, 9, 11, 14, 15, 16, 17, 18, 19 and 20 of an oligonucleotide are 2’-F modified sugar. In some embodiments, an oligonucleotide comprises a 2’-OR modified sugar, wherein R is optionally substituted C1-C6aliphatic. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 or more 2’-OR modified sugars, wherein R is optionally substituted C1-C6aliphatic. In some embodiments, sugar of nucleosides 7, 10, 12 and 13 of an oligonucleotide are independently 2’-OR modified sugars, wherein R is optionally substituted C1-C6aliphatic. In some embodiments, an oligonucleotide comprises a 2’-OMe modified sugar. In some embodiments, an oligonucleotide comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 or more 2’-OMe modified sugars. In some embodiments, an oligonucleotide comprises 2’-OR modified sugar is a 2’-OMe modified sugar.

[0020] In some embodiments, an oligonucleotide can hybridize to a region of a DMD transcript. In some embodiments, a region of a DMD transcript comprises GGCUUCAACUAUCUGAGUGA, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises CGGCAAACUGUUGUCAGAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises GCGGCAAACUGUUGUCAGAA, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises AGCGGCAAACUGUUGUCAGA, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises CAGCGGCAAACUGUUGUCAG, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises GGCAUUGGGCAGCGGCAAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises CUCCAGGAUGGCAUUGGGCA, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprisesGAACUCCAGGAUGGCAUUGG, wherein each U is optionally and independently replaced with T. In some embodiments, a region of a DMD transcript comprises CAGGAACUCCAGGAUGGCAU, wherein each U is optionally and independently replaced with T.

[0021] In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of a DMD transcript. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of a DMD transcript. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of a DMD transcript. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of GGCUUCAACUAUCUGAGUGA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of GGCUUCAACUAUCUGAGUGA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of GGCUUCAACUAUCUGAGUGA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of CGGCAAACUGUUGUCAGAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of CGGCAAACUGUUGUCAGAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of CGGCAAACUGUUGUCAGAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of GCGGCAAACUGUUGUCAGAA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of GCGGCAAACUGUUGUCAGAA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of GCGGCAAACUGUUGUCAGAA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of AGCGGCAAACUGUUGUCAGA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of AGCGGCAAACUGUUGUCAGA, wherein each U is optionally and independently replaced with T. In someembodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of AGCGGCAAACUGUUGUCAGA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of CAGCGGCAAACUGUUGUCAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of CAGCGGCAAACUGUUGUCAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of CAGCGGCAAACUGUUGUCAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of GGCAUUGGGCAGCGGCAAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of GGCAUUGGGCAGCGGCAAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of GGCAUUGGGCAGCGGCAAAC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of CUCCAGGAUGGCAUUGGGCA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of CUCCAGGAUGGCAUUGGGCA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of CUCCAGGAUGGCAUUGGGCA, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of GAACUCCAGGAUGGCAUUGG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases complementary to 15 or more contiguous nucleobases of GAACUCCAGGAUGGCAUUGG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of GAACUCCAGGAUGGCAUUGG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases complementary to 10 or more contiguous nucleobases of CAGGAACUCCAGGAUGGCAU, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobasescomplementary to 15 or more contiguous nucleobases of CAGGAACUCCAGGAUGGCAU, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 20 or more contiguous nucleobases complementary to 20 or more contiguous nucleobases of CAGGAACUCCAGGAUGGCAU, wherein each U is optionally and independently replaced with T.

[0022] In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of UCACUCAGAUAGUUGAAGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of UCACUCAGAUAGUUGAAGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises UCACUCAGAUAGUUGAAGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is UCACUCAGAUAGUUGAAGCC. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of GUUCUGACAACAGUUUGCCG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of GUUCUGACAACAGUUUGCCG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises GUUCUGACAACAGUUUGCCG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is GUUCUGACAACAGUUUGCCG. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of UUCUGACAACAGUUUGCCGC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of UUCUGACAACAGUUUGCCGC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises UUCUGACAACAGUUUGCCGC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is UUCUGACAACAGUUUGCCGC. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of UCUGACAACAGUUUGCCGCU, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of UCUGACAACAGUUUGCCGCU, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises UCUGACAACAGUUUGCCGCU, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is UCUGACAACAGUUUGCCGCU. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of CUGACAACAGUUUGCCGCUG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of CUGACAACAGUUUGCCGCUG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises CUGACAACAGUUUGCCGCUG, whereineach U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is CUGACAACAGUUUGCCGCUG. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of GUUUGCCGCUGCCCAAUGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of GUUUGCCGCUGCCCAAUGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises GUUUGCCGCUGCCCAAUGCC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is GUUUGCCGCUGCCCAAUGCC. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of UGCCCAAUGCCAUCCUGGAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of UGCCCAAUGCCAUCCUGGAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises UGCCCAAUGCCAUCCUGGAG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is UGCCCAAUGCCAUCCUGGAG. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of CCAAUGCCAUCCUGGAGUUC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of CCAAUGCCAUCCUGGAGUUC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises CCAAUGCCAUCCUGGAGUUC, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is CCAAUGCCAUCCUGGAGUUC. In some embodiments, a base sequence of an oligonucleotide comprises 10 or more contiguous nucleobases of AUGCCAUCCUGGAGUUCCUG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises 15 or more contiguous nucleobases of AUGCCAUCCUGGAGUUCCUG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide comprises AUGCCAUCCUGGAGUUCCUG, wherein each U is optionally and independently replaced with T. In some embodiments, a base sequence of an oligonucleotide is AUGCCAUCCUGGAGUUCCUG.

[0023] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising an oligonucleotide described herein, wherein the composition is enriched, relative to a substantially racemic preparation of the oligonucleotide, for the oligonucleotide. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides each of which is an oligonucleotide described herein, wherein oligonucleotides of the plurality share the same constitution and at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of all oligonucleotides in the composition that share the sameconstitution are oligonucleotides of the plurality. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising an oligonucleotide described herein, wherein at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of all oligonucleotides in the composition that share the same constitution as the oligonucleotide are the oligonucleotide. In some embodiments, the present disclosure provides an oligonucleotide composition comprising a plurality of oligonucleotides, wherein oligonucleotides of the plurality share 1) a common base sequence and 2) the same linkage phosphorus stereochemistry independently at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more chiral internucleotidic linkages, wherein oligonucleotides of the plurality are an oligonucleotide described herein and wherein at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the oligonucleotides in the composition that share the common base sequence are oligonucleotides of the plurality. In some embodiments, oligonucleotides of a plurality share the same linkage phosphorus stereochemistry independently at each chiral internucleotidic linkage. In some embodiments, the present disclosure provides an oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of an oligonucleotide described herein (e.g., in Table 1, e.g., in Table 1A, Table 1B, Table 1C). In some embodiments, a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of all oligonucleotides that share the same base sequence as an oligonucleotide having the structure or a pharmaceutically acceptable salt thereof. In some embodiments, a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of all oligonucleotides that share the same constitution as an oligonucleotide having the structure or a pharmaceutically acceptable salt thereof. In some embodiments, a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% based on UV peak area at 260 nm.

[0024] In some embodiments, the present disclosure provides a pharmaceutical composition comprising an oligonucleotide or oligonucleotide composition described herein. In some embodiments, a pharmaceutical composition comprises one or more pharmaceutically acceptable salts of an oligonucleotide. In some embodiments, a pharmaceutical composition is a solution.

[0025] In some embodiments, the present disclosure provides methods using oligonucleotides and compositions described herein. In some embodiments, the present disclosure provides a method for altering splicing of a DMD transcript in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition described herein. In some embodiments, the present disclosure provides a method for providing DMD exon skipping in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition described herein. In some embodiments, the present disclosure provides a method for increasing level of DMD polypeptide in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition described herein. In some embodiments, the present disclosure provides a method for increasing level of DMD activity in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide orcomposition described herein. In some embodiments, the present disclosure provides a method In some embodiments, the present disclosure provides a method for treating muscular dystrophy, comprising administering or delivering to a subject suffering therefrom an effective amount of an oligonucleotide or composition described herein.

[0026] In some embodiments, the present disclosure provides a method for manufacturing or preparing an oligonucleotide or composition described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1. Provided oligonucleotides can provide dose-dependent exon skipping. Oligonucleotides comprising various modifications, such as linkage modifications (e.g., PS, PN (e.g., phosphoryl guanidine linkages such as n001), etc.), sugar modifications (e.g., 2’-F, 2’-OMe, etc.), and stereochemistry and patterns thereof were designed and assessed. H2K mdx cells were plated at 40,000 cells / well in 24 well plates coated with matrigel and differentiation media and allowed to differentiate for 4 days. Following 4 days, differentiated cells were gymnotically treated with 3 uM, 1 uM, or 0.3 uM of indicated oligonucleotides targeting DMD by refreshing the differentiation medium. After 3 hours of incubation, oligonucleotide-containing medium was aspirated and replaced with fresh differentiation medium. Cells were allowed to differentiate for a further 4 days and subsequently harvested. RNA was collected and transcribed into cDNA. Exon skipping was quantified by qPCR. From top to bottom for each oligonucleotide, horizontal bars represent data from treatment with 3 uM, 1 uM, or 0.3 uM of indicated oligonucleotide. Error bars represent SEM.

[0028] Figure 2. Provided oligonucleotides can provide exon skipping. Oligonucleotides comprising various modifications, such as linkage modifications (e.g., PS, PN (e.g., phosphoryl guanidine linkages such as n001), etc.), sugar modifications (e.g., 2’-F, 2’-OMe, etc.), and stereochemistry and patterns thereof were designed and assessed. At day 1, patient-derived immortalized myoblasts containing a deletion in DMD exon 48-50 were seeded at a pre-determined density on matrigel-coated plates in growth medium. At day 2, media was replaced differentiation medium and allowed to differentiate for 4 days. At day 5, cells were dosed gymnotically with 10 uM of indicated oligonucleotides. At day 6, cells were harvested and RNA was collected and transcribed into cDNA. Exon skipping was quantified using qPCR. % skipping efficiency was calculated by normalizing to the housekeeper (SFRS9) and then dividing skipped transcript by total transcript.

[0029] Figure 3. Provided oligonucleotides can provide exon skipping. Oligonucleotides comprising various modifications, such as linkage modifications (e.g., PS, PN (e.g., phosphoryl guanidine linkages such as n001), etc.), sugar modifications (e.g., 2’-F, 2’-OMe, etc.), and stereochemistry and patterns thereof were designed and assessed. At day 1, patient-derived immortalized myoblasts containing a deletion in DMD exon 48-50 were seeded at a pre-determined density on matrigel-coated plates in growth medium. At day 2, media was replaced differentiation medium and cells were dosed gymnotically with either 5 uM or 1 uM of indicated oligonucleotides. Cells were allowed to differentiate for 4 days. At day 6, cells were harvested and RNA was collected and transcribed into cDNA. Exon skipping was quantified using qPCR. Left vertical bar for eacholigonucleotide represents data from treatment with 5 uM of indicated oligonucleotide; right vertical bar for each oligonucleotide represents data from treatment with 1 uM of indicated oligonucleotide. % skipping efficiency was calculated by normalizing to the housekeeper (SFRS9) and then dividing skipped transcript by total transcript. DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0030] Technologies of the present disclosure may be understood more readily by reference to the following detailed description of certain embodiments. Definitions

[0031] As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed. Additionally, general principles of organic chemistry are described in "Organic Chemistry", Thomas Sorrell, University Science Books, Sausalito: 1999, and "March's Advanced Organic Chemistry", 5th Ed., Ed.: Smith, M.B. and March, J., John Wiley & Sons, New York: 2001.

[0032] As used herein in the present disclosure, unless otherwise clear from context, (i) the term “a” or “an” may be understood to mean “at least one”; (ii) the term “or” may be understood to mean “and / or”; (iii) the terms “comprising”, “comprise”, “including” (whether used with “not limited to” or not), and “include” (whether used with “not limited to” or not) may be understood to encompass itemized components or steps whether presented by themselves or together with one or more additional components or steps; (iv) the term “another” may be understood to mean at least an additional / second one or more; (v) the terms “about” and “approximately” may be understood to permit standard variation as would be understood by those of ordinary skill in the art; and (vi) where ranges are provided, endpoints are included.

[0033] Unless otherwise specified, description of oligonucleotides and elements thereof (e.g., base sequence, sugar modifications, internucleotidic linkages, linkage phosphorus stereochemistry, patterns thereof, etc.) is from 5’ to 3’. As those skilled in the art will appreciate, in some embodiments, oligonucleotides may be provided and / or utilized as salt forms, particularly pharmaceutically acceptable salt forms, e.g., sodium salts. As those skilled in the art will also appreciate, in some embodiments, individual oligonucleotides within a composition may be considered to be of the same constitution and / or structure even though, within such composition (e.g., a liquid composition), particular such oligonucleotides might be in different salt form(s) (and may be dissolved and the oligonucleotide chain may exist as an anion form when, e.g., in a liquid composition) at a particular moment in time. For example, those skilled in the art will appreciate that, at a given pH, individual internucleotidic linkages along an oligonucleotide chain may be in an acid (H) form, or in one of a plurality of possible salt forms (e.g., a sodium salt, or a salt of a different cation, depending on which ions might be present in the preparation or composition), and will understand that, so long as their acidforms (e.g., replacing all cations, if any, with H+) are of the same constitution and / or structure, such individual oligonucleotides may properly be considered to be of the same constitution and / or structure.

[0034] Aliphatic: As used herein, “aliphatic” means a straight-chain (i.e., unbranched) or branched, substituted or unsubstituted hydrocarbon chain that is completely saturated or that contains one or more units of unsaturation (but not aromatic), or a substituted or unsubstituted monocyclic, bicyclic, or polycyclic hydrocarbon ring that is completely saturated or that contains one or more units of unsaturation (but not aromatic), or combinations thereof. In some embodiments, aliphatic groups contain 1-50 aliphatic carbon atoms. In some embodiments, aliphatic groups contain 1-20 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-10 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-9 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-8 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-7 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-6 aliphatic carbon atoms. In still other embodiments, aliphatic groups contain 1-5 aliphatic carbon atoms, and in yet other embodiments, aliphatic groups contain 1, 2, 3, or 4 aliphatic carbon atoms. Suitable aliphatic groups include, but are not limited to, linear or branched, substituted or unsubstituted alkyl, alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

[0035] Alkenyl: As used herein, the term “alkenyl” refers to an aliphatic group, as defined herein, having one or more double bonds.

[0036] Alkyl: As used herein, the term “alkyl” is given its ordinary meaning in the art and may include saturated aliphatic groups, including straight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkyl groups, and cycloalkyl substituted alkyl groups. In some embodiments, alkyl has 1-100 carbon atoms. In certain embodiments, a straight chain or branched chain alkyl has about 1-20 carbon atoms in its backbone (e.g., C1-C20for straight chain, C2-C20for branched chain), and alternatively, about 1-10. In some embodiments, cycloalkyl rings have from about 3-10 carbon atoms in their ring structure where such rings are monocyclic, bicyclic, or polycyclic, and alternatively about 5, 6 or 7 carbons in the ring structure. In some embodiments, an alkyl group may be a lower alkyl group, wherein a lower alkyl group comprises 1-4 carbon atoms (e.g., C1-C4for straight chain lower alkyls).

[0037] Alkynyl: As used herein, the term “alkynyl” refers to an aliphatic group, as defined herein, having one or more triple bonds.

[0038] Analog: The term “analog” includes any chemical moiety which differs structurally from a reference chemical moiety or class of moieties, but which is capable of performing at least one function of such a reference chemical moiety or class of moieties. As non-limiting examples, a nucleotide analog differs structurally from a nucleotide but performs at least one function of a nucleotide; a nucleobase analog differs structurally from a nucleobase but performs at least one function of a nucleobase; etc.

[0039] Animal: As used herein, the term “animal” refers to any member of the animal kingdom. In some embodiments, “animal” refers to humans, at any stage of development. In some embodiments, “animal” refers to non-human animals, at any stage of development. In certain embodiments, the non-human animal is amammal (e.g., a rodent, a mouse, a rat, a rabbit, a monkey, a dog, a cat, a sheep, cattle, a primate and / or a pig). In some embodiments, animals include, but are not limited to, mammals, birds, reptiles, amphibians, fish and / or worms. In some embodiments, an animal may be a transgenic animal, a genetically-engineered animal and / or a clone.

[0040] Aryl: The term “aryl", as used herein, used alone or as part of a larger moiety as in “aralkyl,” “aralkoxy,” or “aryloxyalkyl,” refers to monocyclic, bicyclic or polycyclic ring systems having a total of five to thirty ring members, wherein at least one ring in the system is aromatic. In some embodiments, an aryl group is a monocyclic, bicyclic or polycyclic ring system having a total of five to fourteen ring members, wherein at least one ring in the system is aromatic, and wherein each ring in the system contains 3 to 7 ring members. In some embodiments, each monocyclic ring unit is aromatic. In some embodiments, an aryl group is a biaryl group. The term “aryl” may be used interchangeably with the term “aryl ring.” In certain embodiments of the present disclosure, “aryl” refers to an aromatic ring system which includes, but is not limited to, phenyl, biphenyl, naphthyl, binaphthyl, anthracyl and the like, which may bear one or more substituents. Also included within the scope of the term “aryl,” as it is used herein, is a group in which an aromatic ring is fused to one or more non–aromatic rings, such as indanyl, phthalimidyl, naphthimidyl, phenanthridinyl, or tetrahydronaphthyl, and the like.

[0041] Characteristic portion: As used herein, the term “characteristic portion”, in the broadest sense, refers to a portion of a substance whose presence (or absence) correlates with presence (or absence) of a particular feature, attribute, or activity of the substance. In some embodiments, a characteristic portion of a substance is a portion that is found in the substance and in related substances that share the particular feature, attribute or activity, but not in those that do not share the particular feature, attribute or activity. In certain embodiments, a characteristic portion shares at least one functional characteristic with the intact substance. For example, in some embodiments, a “characteristic portion” of a protein or polypeptide is one that contains a continuous stretch of amino acids, or a collection of continuous stretches of amino acids, that together are characteristic of a protein or polypeptide. In some embodiments, each such continuous stretch generally contains at least 2, 5, 10, 15, 20, 50, or more amino acids. In general, a characteristic portion of a substance (e.g., of a protein, antibody, etc.) is one that, in addition to the sequence and / or structural identity specified above, shares at least one functional characteristic with the relevant intact substance. In some embodiments, a characteristic portion may be biologically active.

[0042] Chiral control: As used herein, “chiral control” refers to control of the stereochemical designation of the chiral linkage phosphorus in a chiral internucleotidic linkage within an oligonucleotide. As used herein, a chiral internucleotidic linkage is an internucleotidic linkage whose linkage phosphorus is chiral. In some embodiments, a control is achieved through a chiral element that is absent from the sugar and base moieties of an oligonucleotide, for example, in some embodiments, a control is achieved through use of one or more chiral auxiliaries during oligonucleotide preparation, which chiral auxiliaries often are part of chiral phosphoramidites used during oligonucleotide preparation. In contrast to chiral control, a person havingordinary skill in the art will appreciate that conventional oligonucleotide synthesis which does not use chiral auxiliaries cannot control stereochemistry at a chiral internucleotidic linkage if such conventional oligonucleotide synthesis is used to form the chiral internucleotidic linkage. In some embodiments, the stereochemical designation of each chiral linkage phosphorus in each chiral internucleotidic linkage within an oligonucleotide is controlled.

[0043] Chirally controlled oligonucleotide composition: The terms “chirally controlled oligonucleotide composition”, “chirally controlled nucleic acid composition”, and the like, as used herein, refers to a composition that comprises a plurality of oligonucleotides (or nucleic acids) which share a common base sequence, wherein the plurality of oligonucleotides (or nucleic acids) share the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled or stereodefined internucleotidic linkages, whose chiral linkage phosphorus is Rp or Sp in the composition (“stereodefined”), not a random Rp and Sp mixture as non-chirally controlled internucleotidic linkages). In some embodiments, a chirally controlled oligonucleotide composition comprises a plurality of oligonucleotides (or nucleic acids) that share: 1) a common base sequence, 2) a common pattern of backbone linkages, and 3) a common pattern of backbone phosphorus modifications, wherein the plurality of oligonucleotides (or nucleic acids) share the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled or stereodefined internucleotidic linkages, whose chiral linkage phosphorus is Rp or Sp in the composition (“stereodefined”), not a random Rp and Sp mixture as non-chirally controlled internucleotidic linkages). Level of the plurality of oligonucleotides (or nucleic acids) in a chirally controlled oligonucleotide composition is pre-determined / controlled or enriched (e.g., through chirally controlled oligonucleotide preparation to stereoselectively form one or more chiral internucleotidic linkages) compared to a random level in a non- chirally controlled oligonucleotide composition. In some embodiments, about 1%-100%, (e.g., about 5%- 100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90- 100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a chirally controlled oligonucleotide composition are oligonucleotides of the plurality. In some embodiments, about 1%- 100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%- 100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a chirally controlled oligonucleotide composition that share the common base sequence, the common pattern of backbone linkages, and the common pattern of backbone phosphorus modifications are oligonucleotides of the plurality. In some embodiments, a level is about 1%-100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a composition, or of all oligonucleotides in a composition that share a common base sequence (e.g., of a plurality of oligonucleotide or an oligonucleotide type), or of all oligonucleotides in a composition that share a common base sequence, a common pattern of backbone linkages, and a common pattern of backbone phosphorus modifications, or of all oligonucleotides in a composition that share a common base sequence, a common patter of base modifications, a common pattern of sugar modifications, a common pattern of internucleotidic linkage types, and / or a common pattern of internucleotidic linkage modifications. In some embodiments, the plurality of oligonucleotides share the same stereochemistry at about 1-50 (e.g., about 1-10, 1-20, 5-10, 5-20, 10-15, 10- 20, 10-25, 10-30, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) chiral internucleotidic linkages. In some embodiments, the plurality of oligonucleotides share the same stereochemistry at about 1%-100% (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, or at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%) of chiral internucleotidic linkages. In some embodiments, oligonucleotides (or nucleic acids) of a plurality share the same pattern of sugar and / or nucleobase modifications, in any. In some embodiments, oligonucleotides (or nucleic acids) of a plurality are various forms of the same oligonucleotide (e.g., acid and / or various salts of the same oligonucleotide). In some embodiments, oligonucleotides (or nucleic acids) of a plurality are of the same constitution. In some embodiments, level of the oligonucleotides (or nucleic acids) of the plurality is about 1%-100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides (or nucleic acids) in a composition that share the same constitution as the oligonucleotides (or nucleic acids) of the plurality. In some embodiments, each chiral internucleotidic linkage is a chiral controlled internucleotidic linkage, and the composition is a completely chirally controlled oligonucleotide composition. In some embodiments, oligonucleotides (or nucleic acids) of a plurality are structurally identical. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, typically at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 95%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 96%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 97%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 98%. In some embodiments, a chirally controlled internucleotidic linkage has adiastereopurity of at least 99%. In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is a diastereopurity as described in the present disclosure (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% or more) and nc is the number of chiral linkage phosphorus as described in the present disclosure (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more). In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is a diastereopurity as described in the present disclosure (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% or more) and nc is the number of chirally controlled internucleotidic linkages as described in the present disclosure (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more). In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is 95%-100%. For example, when DS is 99% and nc is 10, the percentage is or is at least 90% ((99%)100.90 = 90%). In some embodiments, level of a plurality of oligonucleotides in a composition is represented as the product of the diastereopurity of each chiral linkage phosphorus. In some embodiments, level of a plurality of oligonucleotides in a composition is represented as the product of the diastereopurity of each chirally controlled internucleotidic linkage in the oligonucleotides. In some embodiments, diastereopurity of an internucleotidic linkage connecting two nucleosides in an oligonucleotide (or nucleic acid) is represented by the diastereopurity of an internucleotidic linkage of a dimer connecting the same two nucleosides, wherein the dimer is prepared using comparable conditions, in some instances, identical synthetic cycle conditions (e.g., for the linkage between Nx and Ny in an oligonucleotide ….NxNy….., the dimer is NxNy). In some embodiments, not all chiral internucleotidic linkages are chiral controlled internucleotidic linkages, and the composition is a partially chirally controlled oligonucleotide composition. In some embodiments, a non-chirally controlled internucleotidic linkage has a diastereopurity of less than about 80%, 75%, 70%, 65%, 60%, 55%, or of about 50%, as typically observed in stereorandom oligonucleotide compositions (e.g., as appreciated by those skilled in the art, from traditional oligonucleotide synthesis, e.g., the phosphoramidite method). In some embodiments, oligonucleotides (or nucleic acids) of a plurality are of the same type. In some embodiments, a chirally controlled oligonucleotide composition comprises non-random or controlled levels of individual oligonucleotide or nucleic acids types. For instance, in some embodiments a chirally controlled oligonucleotide composition comprises one and no more than one oligonucleotide type. In some embodiments, a chirally controlled oligonucleotide composition comprises more than one oligonucleotide type. In some embodiments, a chirally controlled oligonucleotide composition comprises multiple oligonucleotide types. In some embodiments, a chirally controlled oligonucleotide composition is a composition of oligonucleotides of an oligonucleotide type, which composition comprises a non-random or controlled level of a plurality of oligonucleotides of the oligonucleotide type.

[0044] Comparable: The term “comparable” is used herein to describe two (or more) sets of conditions or circumstances that are sufficiently similar to one another to permit comparison of results obtained orphenomena observed. In some embodiments, comparable sets of conditions or circumstances are characterized by a plurality of substantially identical features and one or a small number of varied features. Those of ordinary skill in the art will appreciate that sets of conditions are comparable to one another when characterized by a sufficient number and type of substantially identical features to warrant a reasonable conclusion that differences in results obtained or phenomena observed under the different sets of conditions or circumstances are caused by or indicative of the variation in those features that are varied.

[0045] Cycloaliphatic: The term “cycloaliphatic,” “carbocycle,” “carbocyclyl,” “carbocyclic radical,” and “carbocyclic ring,” are used interchangeably, and as used herein, refer to saturated or partially unsaturated, but non-aromatic, cyclic aliphatic monocyclic, bicyclic, or polycyclic ring systems, as described herein, having, unless otherwise specified, from 3 to 30 ring members. Cycloaliphatic groups include, without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cycloheptyl, cycloheptenyl, cyclooctyl, cyclooctenyl, norbornyl, adamantyl, and cyclooctadienyl. In some embodiments, a cycloaliphatic group has 3–6 carbons. In some embodiments, a cycloaliphatic group is saturated and is cycloalkyl. The term “cycloaliphatic” may also include aliphatic rings that are fused to one or more aromatic or nonaromatic rings, such as decahydronaphthyl or tetrahydronaphthyl. In some embodiments, a cycloaliphatic group is bicyclic. In some embodiments, a cycloaliphatic group is tricyclic. In some embodiments, a cycloaliphatic group is polycyclic. In some embodiments, “cycloaliphatic” refers to C3-C6monocyclic hydrocarbon, or C8-C10bicyclic or polycyclic hydrocarbon, that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule, or a C9-C16polycyclic hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule.

[0046] Heteroaliphatic: The term “heteroaliphatic”, as used herein, is given its ordinary meaning in the art and refers to aliphatic groups as described herein in which one or more carbon atoms are independently replaced with one or more heteroatoms (e.g., oxygen, nitrogen, sulfur, silicon, phosphorus, and the like). In some embodiments, one or more units selected from C, CH, CH2, and CH3are independently replaced by one or more heteroatoms (including oxidized and / or substituted forms thereof). In some embodiments, a heteroaliphatic group is heteroalkyl. In some embodiments, a heteroaliphatic group is heteroalkenyl.

[0047] Heteroalkyl: The term “heteroalkyl”, as used herein, is given its ordinary meaning in the art and refers to alkyl groups as described herein in which one or more carbon atoms are independently replaced with one or more heteroatoms (e.g., oxygen, nitrogen, sulfur, silicon, phosphorus, and the like). Examples of heteroalkyl groups include, but are not limited to, alkoxy, poly(ethylene glycol)-, alkyl-substituted amino, tetrahydrofuranyl, piperidinyl, morpholinyl, etc.

[0048] Heteroaryl: The terms “heteroaryl” and “heteroar–”, as used herein, used alone or as part of a larger moiety, e.g., “heteroaralkyl,” or “heteroaralkoxy,” refer to monocyclic, bicyclic or polycyclic ring systems having a total of five to thirty ring members, wherein at least one ring in the system is aromatic and at least one aromatic ring atom is a heteroatom. In some embodiments, a heteroaryl group is a group having 5 to10 ring atoms (i.e., monocyclic, bicyclic or polycyclic), in some embodiments 5, 6, 9, or 10 ring atoms. In some embodiments, each monocyclic ring unit is aromatic. In some embodiments, a heteroaryl group has 6, 10, or 14 π electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. Heteroaryl groups include, without limitation, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, and pteridinyl. In some embodiments, a heteroaryl is a heterobiaryl group, such as bipyridyl and the like. The terms “heteroaryl” and “heteroar–”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Non-limiting examples include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 4H–quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and pyrido[2,3–b]–1,4–oxazin–3(4H)–one. A heteroaryl group may be monocyclic, bicyclic or polycyclic. The term “heteroaryl” may be used interchangeably with the terms “heteroaryl ring,” “heteroaryl group,” or “heteroaromatic,” any of which terms include rings that are optionally substituted. The term “heteroaralkyl” refers to an alkyl group substituted by a heteroaryl group, wherein the alkyl and heteroaryl portions independently are optionally substituted.

[0049] Heteroatom: The term “heteroatom", as used herein, means an atom that is not carbon or hydrogen. In some embodiments, a heteroatom is boron, oxygen, sulfur, nitrogen, phosphorus, or silicon (including oxidized forms of nitrogen, sulfur, phosphorus, or silicon; charged forms of nitrogen (e.g., quaternized forms, forms as in iminium groups, etc.), phosphorus, sulfur, oxygen; etc.). In some embodiments, a heteroatom is silicon, phosphorus, oxygen, sulfur or nitrogen. In some embodiments, a heteroatom is silicon, oxygen, sulfur or nitrogen. In some embodiments, a heteroatom is oxygen, sulfur or nitrogen.

[0050] Heterocycle: As used herein, the terms “heterocycle,” “heterocyclyl,” “heterocyclic radical,” and “heterocyclic ring", as used herein, are used interchangeably and refer to a monocyclic, bicyclic or polycyclic ring moiety (e.g., 3-30 membered) that is saturated or partially unsaturated and has one or more heteroatom ring atoms. In some embodiments, a heterocyclyl group is a stable 5– to 7–membered monocyclic or 7– to 10– membered bicyclic heterocyclic moiety that is either saturated or partially unsaturated, and having, in addition to carbon atoms, one or more, preferably one to four, heteroatoms, as defined above. When used in reference to a ring atom of a heterocycle, the term "nitrogen" includes substituted nitrogen. As an example, in a saturated or partially unsaturated ring having 0–3 heteroatoms selected from oxygen, sulfur and nitrogen, the nitrogen may be N (as in 3,4–dihydro–2H–pyrrolyl), NH (as in pyrrolidinyl), or+NR (as in N–substituted pyrrolidinyl). A heterocyclic ring can be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure and any of the ring atoms can be optionally substituted. Examples of such saturated or partially unsaturated heterocyclic radicals include, without limitation, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl,oxazolidinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl, and quinuclidinyl. The terms “heterocycle,” “heterocyclyl,” “heterocyclyl ring,” “heterocyclic group,” “heterocyclic moiety,” and “heterocyclic radical,” are used interchangeably herein, and also include groups in which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or cycloaliphatic rings, such as indolinyl, 3H–indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl. A heterocyclyl group may be monocyclic, bicyclic or polycyclic. The term “heterocyclylalkyl” refers to an alkyl group substituted by a heterocyclyl, wherein the alkyl and heterocyclyl portions independently are optionally substituted.

[0051] Identity: As used herein, the term “identity” refers to the overall relatedness between polymeric molecules, e.g., between nucleic acid molecules (e.g., oligonucleotides, DNA, RNA, etc.) and / or between polypeptide molecules. In some embodiments, polymeric molecules are considered to be “substantially identical” to one another if their sequences are at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% identical. Calculation of the percent identity of two nucleic acid or polypeptide sequences, for example, can be performed by aligning the two sequences for optimal comparison purposes (e.g., gaps can be introduced in one or both of a first and a second sequences for optimal alignment and non-identical sequences can be disregarded for comparison purposes). In certain embodiments, the length of a sequence aligned for comparison purposes is at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or substantially 100% of the length of a reference sequence. The nucleotides at corresponding positions are then compared. When a position in the first sequence is occupied by the same residue (e.g., nucleotide or amino acid) as the corresponding position in the second sequence, then the molecules are identical at that position. The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which needs to be introduced for optimal alignment of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm. For example, the percent identity between two nucleotide sequences can be determined using the algorithm of Meyers and Miller (CABIOS, 1989, 4: 11-17), which has been incorporated into the ALIGN program (version 2.0). In some exemplary embodiments, nucleic acid sequence comparisons made with the ALIGN program use a PAM120 weight residue table, a gap length penalty of 12 and a gap penalty of 4. The percent identity between two nucleotide sequences can, alternatively, be determined using the GAP program in the GCG software package using an NWSgapdna.CMP matrix.

[0052] Internucleotidic linkage: As used herein, the phrase “internucleotidic linkage” refers generally to a linkage linking nucleoside units of an oligonucleotide or a nucleic acid. In some embodiments, an internucleotidic linkage is a phosphodiester linkage, as extensively found in naturally occurring DNA and RNA molecules (natural phosphate linkage (−OP(=O)(OH)O−), which as appreciated by those skilled in the art may exist as a salt form). In some embodiments, an internucleotidic linkage is a modified internucleotidic linkage (not a natural phosphate linkage). In some embodiments, an internucleotidic linkage is a “modified internucleotidic linkage” wherein at least one oxygen atom or −OH of a phosphodiester linkage is replaced bya different organic or inorganic moiety. In some embodiments, such an organic or inorganic moiety is selected from =S, =Se, =NR’, –SR’, –SeR’, –N(R’)2, B(R’)3, –S–, –Se–, and –N(R’)–, wherein each R’ is independently as defined and described in the present disclosure. In some embodiments, an internucleotidic linkage is a phosphotriester linkage, phosphorothioate linkage (or phosphorothioate diester linkage, −OP(=O)(SH)O−, which as appreciated by those skilled in the art may exist as a salt form), or phosphorothioate triester linkage. In some embodiments, a modified internucleotidic linkage is a phosphorothioate linkage. In some embodiments, an internucleotidic linkage is one of, e.g., PNA (peptide nucleic acid) or PMO (phosphorodiamidate Morpholino oligomer) linkage. In some embodiments, a modified internucleotidic linkage is a non-negatively charged internucleotidic linkage. In some embodiments, a modified internucleotidic linkage is a neutral internucleotidic linkage (e.g., n001 in certain provided oligonucleotides). It is understood by a person of ordinary skill in the art that an internucleotidic linkage may exist as an anion or cation at a given pH due to the existence of acid or base moieties in the linkage. In some embodiments, a modified internucleotidic linkages is a modified internucleotidic linkages designated as s, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15, s16, s17 and s18 as described in WO 2017 / 210647.

[0053] In vitro: As used herein, the term “in vitro” refers to events that occur in an artificial environment, e.g., in a test tube or reaction vessel, in cell culture, etc., rather than within an organism (e.g., animal, plant and / or microbe).

[0054] In vivo: As used herein, the term “in vivo” refers to events that occur within an organism (e.g., animal, plant and / or microbe).

[0055] Linkage phosphorus: as defined herein, the phrase “linkage phosphorus” is used to indicate that the particular phosphorus atom being referred to is the phosphorus atom present in the internucleotidic linkage, which phosphorus atom corresponds to the phosphorus atom of a phosphodiester internucleotidic linkage as occurs in naturally occurring DNA and RNA. In some embodiments, a linkage phosphorus atom is in a modified internucleotidic linkage, wherein each oxygen atom of a phosphodiester linkage is optionally and independently replaced by an organic or inorganic moiety. In some embodiments, a linkage phosphorus atom is chiral (e.g., as in phosphorothioate internucleotidic linkages). In some embodiments, a linkage phosphorus atom is achiral (e.g., as in natural phosphate linkages).

[0056] Modified nucleobase: The terms "modified nucleobase", "modified base" and the like refer to a chemical moiety which is chemically distinct from a nucleobase, but which is capable of performing at least one function of a nucleobase. In some embodiments, a modified nucleobase is a nucleobase which comprises a modification. In some embodiments, a modified nucleobase is capable of at least one function of a nucleobase, e.g., forming a moiety in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases. In some embodiments, a modified nucleobase is substituted A, T, C, G, or U, or a substituted tautomer of A, T, C, G, or U. In some embodiments, a modified nucleobase in the context of oligonucleotides refer to a nucleobase that is not A, T, C, G or U.

[0057] Modified nucleoside: The term "modified nucleoside" refers to a moiety derived from orchemically similar to a natural nucleoside, but which comprises a chemical modification which differentiates it from a natural nucleoside. Non-limiting examples of modified nucleosides include those which comprise a modification at the base and / or the sugar. Non-limiting examples of modified nucleosides include those with a 2’ modification at a sugar. Non-limiting examples of modified nucleosides also include abasic nucleosides (which lack a nucleobase). In some embodiments, a modified nucleoside is capable of at least one function of a nucleoside, e.g., forming a moiety in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases.

[0058] Modified nucleotide: The term “modified nucleotide” includes any chemical moiety which differs structurally from a natural nucleotide but is capable of performing at least one function of a natural nucleotide. In some embodiments, a modified nucleotide comprises a modification at a sugar, base and / or internucleotidic linkage. In some embodiments, a modified nucleotide comprises a modified sugar, modified nucleobase and / or modified internucleotidic linkage. In some embodiments, a modified nucleotide is capable of at least one function of a nucleotide, e.g., forming a subunit in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases.

[0059] Modified sugar: The term “modified sugar” refers to a moiety that can replace a sugar. A modified sugar mimics the spatial arrangement, electronic properties, or some other physicochemical property of a sugar. In some embodiments, as described in the present disclosure, a modified sugar is substituted ribose or deoxyribose. In some embodiments, a modified sugar comprises a 2’-modification. Examples of useful 2’- modification are widely utilized in the art and described herein. In some embodiments, a 2’-modification is 2’-F. In some embodiments, a 2’-modification is 2’-OR, wherein R is optionally substituted C1-10aliphatic. In some embodiments, a 2’-modification is 2’-OMe. In some embodiments, a 2’-modification is 2’-MOE. In some embodiments, a modified sugar is a bicyclic sugar (e.g., a sugar used in LNA, BNA, etc.). In some embodiments, in the context of oligonucleotides, a modified sugar is a sugar that is not ribose or deoxyribose as typically found in natural RNA or DNA.

[0060] Nucleic acid: The term “nucleic acid”, as used herein, includes any nucleotides and polymers thereof. The term “polynucleotide”, as used herein, refers to a polymeric form of nucleotides of any length, either ribonucleotides (RNA) or deoxyribonucleotides (DNA) or a combination thereof. These terms refer to the primary structure of the molecules and, thus, include double- and single-stranded DNA, and double- and single-stranded RNA. These terms include, as equivalents, analogs of either RNA or DNA comprising modified nucleotides and / or modified polynucleotides, such as, though not limited to, methylated, protected and / or capped nucleotides or polynucleotides. The terms encompass poly- or oligo-ribonucleotides (RNA) and poly- or oligo-deoxyribonucleotides (DNA); RNA or DNA derived from N-glycosides or C-glycosides of nucleobases and / or modified nucleobases; nucleic acids derived from sugars and / or modified sugars; and nucleic acids derived from phosphate bridges and / or modified internucleotidic linkages. The term encompasses nucleic acids containing any combinations of nucleobases, modified nucleobases, sugars, modified sugars, phosphate bridges or modified internucleotidic linkages. Examples include, and are notlimited to, nucleic acids containing ribose moieties, nucleic acids containing deoxy-ribose moieties, nucleic acids containing both ribose and deoxyribose moieties, nucleic acids containing ribose and modified ribose moieties. Unless otherwise specified, the prefix poly- refers to a nucleic acid containing 2 to about 10,000 nucleotide monomer units and wherein the prefix oligo- refers to a nucleic acid containing 2 to about 200 nucleotide monomer units.

[0061] Nucleobase: The term “nucleobase” refers to the parts of nucleic acids that are involved in the hydrogen-bonding that binds one nucleic acid strand to another complementary strand in a sequence specific manner. The most common naturally-occurring nucleobases are adenine (A), guanine (G), uracil (U), cytosine (C), and thymine (T). In some embodiments, a naturally-occurring nucleobases are modified adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a naturally-occurring nucleobases are methylated adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a nucleobase comprises a heteroaryl ring wherein a ring atom is nitrogen, and when in a nucleoside, the nitrogen is bonded to a sugar moiety. In some embodiments, a nucleobase comprises a heterocyclic ring wherein a ring atom is nitrogen, and when in a nucleoside, the nitrogen is bonded to a sugar moiety. In some embodiments, a nucleobase is a “modified nucleobase,” a nucleobase other than adenine (A), guanine (G), uracil (U), cytosine (C), and thymine (T). In some embodiments, a modified nucleobase is substituted A, T, C, G or U. In some embodiments, a modified nucleobase is a substituted tautomer of A, T, C, G, or U. In some embodiments, a modified nucleobases is methylated adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a modified nucleobase mimics the spatial arrangement, electronic properties, or some other physicochemical property of the nucleobase and retains the property of hydrogen-bonding that binds one nucleic acid strand to another in a sequence specific manner. In some embodiments, a modified nucleobase can pair with all of the five naturally occurring bases (uracil, thymine, adenine, cytosine, or guanine) without substantially affecting the melting behavior, recognition by intracellular enzymes or activity of the oligonucleotide duplex. As used herein, the term “nucleobase” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified nucleobases and nucleobase analogs. In some embodiments, a nucleobase is optionally substituted A, T, C, G, or U, or an optionally substituted tautomer of A, T, C, G, or U. In some embodiments, a “nucleobase” refers to a nucleobase unit in an oligonucleotide or a nucleic acid (e.g., A, T, C, G or U as in an oligonucleotide or a nucleic acid).

[0062] Nucleoside: The term “nucleoside” refers to a moiety wherein a nucleobase or a modified nucleobase is covalently bound to a sugar or a modified sugar. In some embodiments, a nucleoside is a natural nucleoside, e.g., adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, or deoxycytidine. In some embodiments, a nucleoside is a modified nucleoside, e.g., a substituted natural nucleoside selected from adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, and deoxycytidine. In some embodiments, a nucleoside is a modified nucleoside, e.g., a substituted tautomer of a natural nucleoside selected from adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, and deoxycytidine. In some embodiments, a “nucleoside” refers to a nucleosideunit in an oligonucleotide or a nucleic acid.

[0063] Nucleotide: The term “nucleotide” as used herein refers to a monomeric unit of a polynucleotide that consists of a nucleobase, a sugar, and one or more internucleotidic linkages (e.g., phosphate linkages in natural DNA and RNA). The naturally occurring bases [guanine, (G), adenine, (A), cytosine, (C), thymine, (T), and uracil (U)] are derivatives of purine or pyrimidine, though it should be understood that naturally and non-naturally occurring base analogs are also included. The naturally occurring sugar is the pentose (five- carbon sugar) deoxyribose (which forms DNA) or ribose (which forms RNA), though it should be understood that naturally and non-naturally occurring sugar analogs are also included. Nucleotides are linked via internucleotidic linkages to form nucleic acids, or polynucleotides. Many internucleotidic linkages are known in the art (such as, though not limited to, phosphate, phosphorothioates, boranophosphates and the like). Artificial nucleic acids include PNAs (peptide nucleic acids), phosphotriesters, phosphorothionates, H- phosphonates, phosphoramidates, boranophosphates, methylphosphonates, phosphonoacetates, thiophosphonoacetates and other variants of the phosphate backbone of native nucleic acids, such as those described herein. In some embodiments, a natural nucleotide comprises a naturally occurring base, sugar and internucleotidic linkage. As used herein, the term “nucleotide” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified nucleotides and nucleotide analogs. In some embodiments, a “nucleotide” refers to a nucleotide unit in an oligonucleotide or a nucleic acid.

[0064] Oligonucleotide: The term "oligonucleotide" refers to a polymer or oligomer of nucleotides, and may contain any combination of natural and non-natural nucleobases, sugars, and internucleotidic linkages.

[0065] Oligonucleotides can be single-stranded or double-stranded. A single-stranded oligonucleotide can have double-stranded regions (formed by two portions of the single-stranded oligonucleotide) and a double-stranded oligonucleotide, which comprises two oligonucleotide chains, can have single-stranded regions for example, at regions where the two oligonucleotide chains are not complementary to each other. Example oligonucleotides include, but are not limited to structural genes, genes including control and termination regions, self-replicating systems such as viral or plasmid DNA, single-stranded and double- stranded RNAi agents and other RNA interference reagents (RNAi agents or iRNA agents), shRNA, antisense oligonucleotides, ribozymes, microRNAs, microRNA mimics, supermirs, aptamers, antimirs, antagomirs, Ul adaptors, triplex-forming oligonucleotides, G-quadruplex oligonucleotides, RNA activators, immuno- stimulatory oligonucleotides, and decoy oligonucleotides.

[0066] Oligonucleotides of the present disclosure can be of various lengths. In particular embodiments, oligonucleotides can range from about 2 to about 200 nucleosides in length. In various related embodiments, oligonucleotides, single-stranded, double-stranded, or triple-stranded, can range in length from about 4 to about 10 nucleosides, from about 10 to about 50 nucleosides, from about 20 to about 50 nucleosides, from about 15 to about 30 nucleosides, from about 20 to about 30 nucleosides in length. In some embodiments, an oligonucleotide is from about 9 to about 39 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about26 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 27 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 28 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 29 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 30 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 31 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 32 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 60 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 50 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 40 nucleosides in length. In some embodiments, an oligonucleotide is from about 30 to about 40 nucleosides in length. In some embodiments, the oligonucleotide is at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 nucleosides in length. In some embodiments, an oligonucleotide is at least 4 nucleosides in length. In some embodiments, an oligonucleotide is at least 5 nucleosides in length. In some embodiments, an oligonucleotide is at least 6 nucleosides in length. In some embodiments, an oligonucleotide is at least 7 nucleosides in length. In some embodiments, an oligonucleotide is at least 8 nucleosides in length. In some embodiments, an oligonucleotide is at least 9 nucleosides in length. In some embodiments, an oligonucleotide is at least 10 nucleosides in length. In some embodiments, an oligonucleotide is at least 11 nucleosides in length. In some embodiments, an oligonucleotide is at least 12 nucleosides in length. In some embodiments, an oligonucleotide is at least 15 nucleosides in length. In some embodiments, an oligonucleotide is at least 15 nucleosides in length. In some embodiments, an oligonucleotide is at least 16 nucleosides in length. In some embodiments, an oligonucleotide is at least 17 nucleosides in length. In some embodiments, an oligonucleotide is at least 18 nucleosides in length. In some embodiments, an oligonucleotide is at least 19 nucleosides in length. In some embodiments, an oligonucleotide is at least 20 nucleosides in length. In some embodiments, an oligonucleotide is at least 25 nucleosides in length. In some embodiments, an oligonucleotide is at least 26 nucleosides in length. In some embodiments, an oligonucleotide is at least 27 nucleosides in length. In some embodiments, an oligonucleotide is at least 28 nucleosides in length. In some embodiments, an oligonucleotide is at least 29 nucleosides in length. In some embodiments, an oligonucleotide is at least 30 nucleosides in length. In some embodiments, an oligonucleotide is at least 31 nucleosides in length. In some embodiments, an oligonucleotide is at least 32 nucleosides in length. In some embodiments, an oligonucleotide is at least 33 nucleosides in length. In some embodiments, an oligonucleotide is at least 34 nucleosides in length. In some embodiments, an oligonucleotide is at least 35 nucleosides in length. In some embodiments, an oligonucleotide is at least 36 nucleosides in length. In some embodiments, an oligonucleotide is at least 37 nucleosides in length. In some embodiments, an oligonucleotide is at least 38 nucleosides in length. In some embodiments, an oligonucleotide is at least 39 nucleosides in length. In some embodiments, an oligonucleotide is at least 40 nucleosides in length. In some embodiments, an oligonucleotide is 25 nucleosides in length. In some embodiments, an oligonucleotide is 26 nucleosides in length. In some embodiments, an oligonucleotide is 27 nucleosides in length. In some embodiments, an oligonucleotide is 28 nucleosides in length. In someembodiments, an oligonucleotide is 29 nucleosides in length. In some embodiments, an oligonucleotide is 30 nucleosides in length. In some embodiments, an oligonucleotide is 31 nucleosides in length. In some embodiments, an oligonucleotide is 32 nucleosides in length. In some embodiments, an oligonucleotide is 33 nucleosides in length. In some embodiments, an oligonucleotide is 34 nucleosides in length. In some embodiments, an oligonucleotide is 35 nucleosides in length. In some embodiments, an oligonucleotide is 36 nucleosides in length. In some embodiments, an oligonucleotide is 37 nucleosides in length. In some embodiments, an oligonucleotide is 38 nucleosides in length. In some embodiments, an oligonucleotide is 39 nucleosides in length. In some embodiments, an oligonucleotide is 40 nucleosides in length. In some embodiments, each nucleoside counted in an oligonucleotide length independently comprises a nucleobase comprising a ring having at least one nitrogen ring atom. In some embodiments, each nucleoside counted in an oligonucleotide length independently comprises A, T, C, G, or U, or optionally substituted A, T, C, G, or U, or an optionally substituted tautomer of A, T, C, G or U.

[0067] Oligonucleotide type: As used herein, the phrase “oligonucleotide type” is used to define an oligonucleotide that has a particular base sequence, pattern of backbone linkages (i.e., pattern of internucleotidic linkage types, for example, phosphate, phosphorothioate, phosphorothioate triester, etc.), pattern of backbone chiral centers [i.e., pattern of linkage phosphorus stereochemistry (Rp / Sp)], and pattern of backbone phosphorus modifications. In some embodiments, oligonucleotides of a common designated “type” are structurally identical to one another.

[0068] One of skill in the art will appreciate that synthetic methods of the present disclosure provide for a degree of control during the synthesis of an oligonucleotide strand such that each nucleotide unit of the oligonucleotide strand can be designed and / or selected in advance to have a particular stereochemistry at the linkage phosphorus and / or a particular modification at the linkage phosphorus, and / or a particular base, and / or a particular sugar. In some embodiments, an oligonucleotide strand is designed and / or selected in advance to have a particular combination of stereocenters at the linkage phosphorus. In some embodiments, an oligonucleotide strand is designed and / or determined to have a particular combination of modifications at the linkage phosphorus. In some embodiments, an oligonucleotide strand is designed and / or selected to have a particular combination of bases. In some embodiments, an oligonucleotide strand is designed and / or selected to have a particular combination of one or more of the above structural characteristics. In some embodiments, the present disclosure provides compositions comprising or consisting of a plurality of oligonucleotide molecules (e.g., chirally controlled oligonucleotide compositions). In some embodiments, all such molecules are of the same type (i.e., are structurally identical to one another). In some embodiments, however, provided compositions comprise a plurality of oligonucleotides of different types, typically in pre-determined relative amounts.

[0069] Optionally Substituted: As described herein, compounds of the disclosure may contain optionally substituted, substituted and / or unsubstituted moieties. In general, the term “substituted,” means that one or more hydrogens of the designated moiety are independently replaced with a substituent. Unless otherwiseindicated, an “optionally substituted” group may independently have a substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with two or more substituents, the substituents may be either the same or different at every position. In some embodiments, an optionally substituted group is unsubstituted. In some embodiments, an optionally substituted group is substituted. Various substituents are described below.

[0070] Monovalent substituents are independently halogen; –aliphatic, eteroaliphatic having 1-5 heteroatoms independently selected fromnitrogen, oxygen, sulfur, silicon and phosphorus, C6-10(e.g., C6, C10, etc.) aryl, 5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur, −6, 9, 10, etc.) membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur),embered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur), a 3-10 (e.g., 3-6, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered, monocyclic, bicyclic, or polycyclic, saturated, or partially unsaturated ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, sulfur, silicon and phosphorus, or, notwithstanding the definition above, two independent occurrences of R°, taken together with their intervening atom(s), form a 3- 10 (e.g., 3-6, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered, monocyclic, bicyclic, or polycyclic, saturated, partially unsaturated or aromatic ring (for aromatic ring, 5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered) having, in addition to the intervening atom(s), 0-5 heteroatoms independently selected from nitrogen, oxygen, sulfur, silicon and phosphorus, which may be substituted as defined below.

[0071] Monovalent substituents on R° (or the ring formed by taking two independent occurrences of R° together with their intervening atoms), are independently halogen, –(( 2OSiRl3, -C(O)SRl, –(C1–4 straight or branched alkylene)C(O)ORl, or –SSRlwherein each Rlis unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from C1–4 aliphatic, –CH2Ph, –O(CH2)0–1Ph, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur. Divalent substituents on a saturated carbon atom of R° are independently =O or =S.

[0072] Divalent substituents are independently the following: =O, =S, =NNR*2, =NNHC(O)R*, =NNHC(O)OR*, =NNHS(O)2R*, =NR*, =NOR*, −O(C(R*2))2–3O−, or −S(C(R*2))2–3S−, wherein each independent occurrence of R*is selected from hydrogen, C1-6 aliphatic which may be substituted as defined below, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur. Divalent substituents that are bound to vicinal substitutable carbons of an “optionally substituted” group are independently −O(CR*2)2–3O−, wherein each independent occurrence of R*is selected from hydrogen, C1-6 aliphatic which may be substituted as defined below, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0073] Substituents on the aliphatic group of R*are independently halogen, –Rl, -(haloRl), –OH, −ORl, –O(haloRl), –CN, –C(O)OH, –C(O)ORl, –NH2, –NHRl, –NRl2, or –NO2, wherein each Rlis unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C1–4 aliphatic, –CH2Ph, –O(CH2)0–1Ph, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0074] Substituents on a substitutable nitrogen are independently –R†, −NR†2, −C(O)R†, –C(O)OR†, – C(O)C(O)R†, –C(O)CH2C(O)R†, –S(O)2R†, –S(O)2NR†2, −C(S)NR†2, –C(NH)NR†2, or –N(R†)S(O)2R†; wherein each R†is independently hydrogen, C1–6aliphatic which may be substituted as defined below, unsubstituted –OPh, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or, notwithstanding the definition above, two independent occurrences of R†, taken together with their intervening atom(s) form an unsubstituted 3–12 (e.g., 3-10, 3-6, 5-10, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered saturated, partially unsaturated, or aryl mono– or bicyclic ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0075] Substituents on the aliphatic group of R†are independently halogen, −Rl, -(haloRl), −OH, –ORl, –O(haloRl), –CN, –C(O)OH, –C(O)ORl, –NH2, –NHRl, –NRl2, or –NO2, wherein each Rlis unsubstitutedor where preceded by “halo” is substituted only with one or more halogens, and is independently C1–4 aliphatic, –CH2Ph, –O(CH2)0–1Ph, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0076] P-modification: as used herein, the term “P-modification” refers to any modification at the linkage phosphorus other than a stereochemical modification. In some embodiments, a P-modification comprises addition, substitution, or removal of a pendant moiety covalently attached to a linkage phosphorus.

[0077] Partially unsaturated: As used herein, the term “partially unsaturated” refers to a ring moiety that includes at least one double or triple bond. The term “partially unsaturated” is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aryl or heteroaryl moieties, as herein defined.

[0078] Pharmaceutical composition: As used herein, the term “pharmaceutical composition” refers to an active agent, formulated together with one or more pharmaceutically acceptable carriers. In some embodiments, an active agent is present in unit dose amount appropriate for administration in a therapeutic regimen that shows a statistically significant probability of achieving a predetermined therapeutic effect when administered to a relevant population. In some embodiments, pharmaceutical compositions may be specially formulated for administration in solid or liquid form, including those adapted for the following: oral administration, for example, drenches (aqueous or non-aqueous solutions or suspensions), tablets, e.g., those targeted for buccal, sublingual, and systemic absorption, boluses, powders, granules, pastes for application to the tongue; parenteral administration, for example, by subcutaneous, intramuscular, intravenous or epidural injection as, for example, a sterile solution or suspension, or sustained-release formulation; topical application, for example, as a cream, ointment, or a controlled-release patch or spray applied to the skin, lungs, or oral cavity; intravaginally or intrarectally, for example, as a pessary, cream, or foam; sublingually; ocularly; transdermally; or nasally, pulmonary, and to other mucosal surfaces.

[0079] Pharmaceutically acceptable: As used herein, the phrase “pharmaceutically acceptable” refers to those compounds, materials, compositions and / or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio.

[0080] Pharmaceutically acceptable carrier: As used herein, the term “pharmaceutically acceptable carrier” means a pharmaceutically-acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, or solvent encapsulating material, involved in carrying or transporting the subject compound from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as pharmaceutically-acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and itsderivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen- free water; isotonic saline; Ringer’s solution; ethyl alcohol; pH buffered solutions; polyesters, polycarbonates and / or polyanhydrides; and other non-toxic compatible substances employed in pharmaceutical formulations.

[0081] Pharmaceutically acceptable salt: The term “pharmaceutically acceptable salt”, as used herein, refers to salts of such compounds that are appropriate for use in pharmaceutical contexts, i.e., salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit / risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge, et al. describes pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 66: 1-19 (1977). In some embodiments, pharmaceutically acceptable salt include, but are not limited to, nontoxic acid addition salts, which are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. In some embodiments, pharmaceutically acceptable salts include, but are not limited to, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2- hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. In some embodiments, a provided compound comprises one or more acidic groups, e.g., an oligonucleotide, and a pharmaceutically acceptable salt is an alkali, alkaline earth metal, or ammonium (e.g., an ammonium salt of N(R)3, wherein each R is independently defined and described in the present disclosure) salt. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. In some embodiments, a pharmaceutically acceptable salt is a sodium salt. In some embodiments, a pharmaceutically acceptable salt is a potassium salt. In some embodiments, a pharmaceutically acceptable salt is a calcium salt. In some embodiments, pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, alkyl having from 1 to 6 carbon atoms, sulfonate and aryl sulfonate. In some embodiments, a provided compound comprises more than one acid groups, for example, an oligonucleotide may comprise two or more acidic groups (e.g., in natural phosphate linkages and / or modified internucleotidic linkages). Insome embodiments, a pharmaceutically acceptable salt, or generally a salt, of such a compound comprises two or more cations, which can be the same or different. In some embodiments, in a pharmaceutically acceptable salt (or generally, a salt), all ionizable hydrogen (e.g., in an aqueous solution with a pKa no more than about 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2; in some embodiments, no more than about 7; in some embodiments, no more than about 6; in some embodiments, no more than about 5; in some embodiments, no more than about 4; in some embodiments, no more than about 3) in the acidic groups are replaced with cations. In some embodiments, each phosphorothioate and phosphate group independently exists in its salt form (e.g., if sodium salt, −O−P(O)(SNa)−O− and −O−P(O)(ONa)−O−, respectively). In some embodiments, each phosphorothioate and phosphate internucleotidic linkage independently exists in its salt form (e.g., if sodium salt, −O−P(O)(SNa)−O− and −O−P(O)(ONa)−O−, respectively). In some embodiments, a pharmaceutically acceptable salt is a sodium salt of an oligonucleotide. In some embodiments, a pharmaceutically acceptable salt is a sodium salt of an oligonucleotide, wherein each acidic phosphate and modified phosphate group (e.g., phosphorothioate, phosphate, etc.), if any, exists as a salt form (all sodium salt).

[0082] Predetermined: By predetermined (or pre-determined) is meant deliberately selected or non- random or controlled, for example as opposed to randomly occurring, random, or achieved without control. Those of ordinary skill in the art, reading the present specification, will appreciate that the present disclosure provides technologies that permit selection of particular chemistry and / or stereochemistry features to be incorporated into oligonucleotide compositions, and further permits controlled preparation of oligonucleotide compositions having such chemistry and / or stereochemistry features. Such provided compositions are “predetermined” as described herein. Compositions that may contain certain oligonucleotides because they happen to have been generated through a process that are not controlled to intentionally generate the particular chemistry and / or stereochemistry features are not “predetermined” compositions. In some embodiments, a predetermined composition is one that can be intentionally reproduced (e.g., through repetition of a controlled process). In some embodiments, a predetermined level of a plurality of oligonucleotides in a composition means that the absolute amount, and / or the relative amount (ratio, percentage, etc.) of the plurality of oligonucleotides in the composition is controlled. In some embodiments, a predetermined level of a plurality of oligonucleotides in a composition is achieved through chirally controlled oligonucleotide preparation.

[0083] Protecting group: The term “protecting group,” as used herein, is well known in the art and includes those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rdedition, John Wiley & Sons, 1999, the entirety of which is incorporated herein by reference. Also included are those protecting groups specially adapted for nucleoside and nucleotide chemistry described in Current Protocols in Nucleic Acid Chemistry, edited by Serge L. Beaucage et al.06 / 2012, the entirety of Chapter 2 is incorporated herein by reference. Suitable amino–protecting groups include methyl carbamate, ethyl carbamante, 9–fluorenylmethyl carbamate (Fmoc), 9–(2–sulfo)fluorenylmethyl carbamate, 9–(2,7– dibromo)fluoroenylmethyl carbamate, 2,7–di–t–butyl–[9–(10,10–dioxo–10,10,10,10– tetrahydrothioxanthyl)]methyl carbamate (DBD–Tmoc), 4–methoxyphenacyl carbamate (Phenoc), 2,2,2–trichloroethyl carbamate (Troc), 2–trimethylsilylethyl carbamate (Teoc), 2–phenylethyl carbamate (hZ), 1–(1– adamantyl)–1–methylethyl carbamate (Adpoc), 1,1–dimethyl–2–haloethyl carbamate, 1,1–dimethyl–2,2– dibromoethyl carbamate (DB–t–BOC), 1,1–dimethyl–2,2,2–trichloroethyl carbamate (TCBOC), 1–methyl–1– (4–biphenylyl)ethyl carbamate (Bpoc), 1–(3,5–di–t–butylphenyl)–1–methylethyl carbamate (t–Bumeoc), 2– (2’– and 4’–pyridyl)ethyl carbamate (Pyoc), 2–(N,N–dicyclohexylcarboxamido)ethyl carbamate, t–butyl carbamate (BOC), 1–adamantyl carbamate (Adoc), vinyl carbamate (Voc), allyl carbamate (Alloc), 1– isopropylallyl carbamate (Ipaoc), cinnamyl carbamate (Coc), 4–nitrocinnamyl carbamate (Noc), 8–quinolyl carbamate, N–hydroxypiperidinyl carbamate, alkyldithio carbamate, benzyl carbamate (Cbz), p– methoxybenzyl carbamate (Moz), p–nitobenzyl carbamate, p–bromobenzyl carbamate, p–chlorobenzyl carbamate, 2,4–dichlorobenzyl carbamate, 4–methylsulfinylbenzyl carbamate (Msz), 9–anthrylmethyl carbamate, diphenylmethyl carbamate, 2–methylthioethyl carbamate, 2–methylsulfonylethyl carbamate, 2–(p– toluenesulfonyl)ethyl carbamate, [2–(1,3–dithianyl)]methyl carbamate (Dmoc), 4–methylthiophenyl carbamate (Mtpc), 2,4–dimethylthiophenyl carbamate (Bmpc), 2–phosphonioethyl carbamate (Peoc), 2– triphenylphosphonioisopropyl carbamate (Ppoc), 1,1–dimethyl–2–cyanoethyl carbamate, m–chloro–p– acyloxybenzyl carbamate, p–(dihydroxyboryl)benzyl carbamate, 5–benzisoxazolylmethyl carbamate, 2– (trifluoromethyl)–6–chromonylmethyl carbamate (Tcroc), m–nitrophenyl carbamate, 3,5–dimethoxybenzyl carbamate, o–nitrobenzyl carbamate, 3,4–dimethoxy–6–nitrobenzyl carbamate, phenyl(o–nitrophenyl)methyl carbamate, phenothiazinyl–(10)–carbonyl derivative, N’–p–toluenesulfonylaminocarbonyl derivative, N’– phenylaminothiocarbonyl derivative, t–amyl carbamate, S–benzyl thiocarbamate, p–cyanobenzyl carbamate, cyclobutyl carbamate, cyclohexyl carbamate, cyclopentyl carbamate, cyclopropylmethyl carbamate, p– decyloxybenzyl carbamate, 2,2–dimethoxycarbonylvinyl carbamate, o–(N,N–dimethylcarboxamido)benzyl carbamate, 1,1–dimethyl–3–(N,N–dimethylcarboxamido)propyl carbamate, 1,1–dimethylpropynyl carbamate, di(2–pyridyl)methyl carbamate, 2–furanylmethyl carbamate, 2–iodoethyl carbamate, isoborynl carbamate, isobutyl carbamate, isonicotinyl carbamate, p–(p’–methoxyphenylazo)benzyl carbamate, 1–methylcyclobutyl carbamate, 1–methylcyclohexyl carbamate, 1–methyl–1–cyclopropylmethyl carbamate, 1–methyl–1–(3,5– dimethoxyphenyl)ethyl carbamate, 1–methyl–1–(p–phenylazophenyl)ethyl carbamate, 1–methyl–1– phenylethyl carbamate, 1–methyl–1–(4–pyridyl)ethyl carbamate, phenyl carbamate, p–(phenylazo)benzyl carbamate, 2,4,6–tri–t–butylphenyl carbamate, 4–(trimethylammonium)benzyl carbamate, 2,4,6– trimethylbenzyl carbamate, formamide, acetamide, chloroacetamide, trichloroacetamide, trifluoroacetamide, phenylacetamide, 3–phenylpropanamide, picolinamide, 3–pyridylcarboxamide, N–benzoylphenylalanyl derivative, benzamide, p–phenylbenzamide, o–nitophenylacetamide, o–nitrophenoxyacetamide, acetoacetamide, (N’–dithiobenzyloxycarbonylamino)acetamide, 3–(p–hydroxyphenyl)propanamide, 3–(o– nitrophenyl)propanamide, 2–methyl–2–(o–nitrophenoxy)propanamide, 2–methyl–2–(o– phenylazophenoxy)propanamide, 4–chlorobutanamide, 3–methyl–3–nitrobutanamide, o–nitrocinnamide, N– acetylmethionine derivative, o–nitrobenzamide, o–(benzoyloxymethyl)benzamide, 4,5–diphenyl–3–oxazolin– 2–one, N–phthalimide, N–dithiasuccinimide (Dts), N–2,3–diphenylmaleimide, N–2,5–dimethylpyrrole, N–1,1,4,4–tetramethyldisilylazacyclopentane adduct (STABASE), 5–substituted 1,3–dimethyl–1,3,5– triazacyclohexan–2–one, 5–substituted 1,3–dibenzyl–1,3,5–triazacyclohexan–2–one, 1–substituted 3,5– dinitro–4–pyridone, N–methylamine, N–allylamine, N–[2–(trimethylsilyl)ethoxy]methylamine (SEM), N–3– acetoxypropylamine, N–(1–isopropyl–4–nitro–2–oxo–3–pyroolin–3–yl)amine, quaternary ammonium salts, N–benzylamine, N–di(4–methoxyphenyl)methylamine, N–5–dibenzosuberylamine, N–triphenylmethylamine (Tr), N–[(4–methoxyphenyl)diphenylmethyl]amine (MMTr), N–9–phenylfluorenylamine (PhF), N–2,7– dichloro–9–fluorenylmethyleneamine, N–ferrocenylmethylamino (Fcm), N–2–picolylamino N’–oxide, N– 1,1–dimethylthiomethyleneamine, N–benzylideneamine, N–p–methoxybenzylideneamine, N– diphenylmethyleneamine, N–[(2–pyridyl)mesityl]methyleneamine, N–(N’,N’– dimethylaminomethylene)amine, N,N’–isopropylidenediamine, N–p–nitrobenzylideneamine, N– salicylideneamine, N–5–chlorosalicylideneamine, N–(5–chloro–2–hydroxyphenyl)phenylmethyleneamine, N–cyclohexylideneamine, N–(5,5–dimethyl–3–oxo–1–cyclohexenyl)amine, N–borane derivative, N– diphenylborinic acid derivative, N–[phenyl(pentacarbonylchromium– or tungsten)carbonyl]amine, N–copper chelate, N–zinc chelate, N–nitroamine, N–nitrosoamine, amine N–oxide, diphenylphosphinamide (Dpp), dimethylthiophosphinamide (Mpt), diphenylthiophosphinamide (Ppt), dialkyl phosphoramidates, dibenzyl phosphoramidate, diphenyl phosphoramidate, benzenesulfenamide, o–nitrobenzenesulfenamide (Nps), 2,4– dinitrobenzenesulfenamide, pentachlorobenzenesulfenamide, 2–nitro–4–methoxybenzenesulfenamide, triphenylmethylsulfenamide, 3–nitropyridinesulfenamide (Npys), p–toluenesulfonamide (Ts), benzenesulfonamide, 2,3,6,–trimethyl–4–methoxybenzenesulfonamide (Mtr), 2,4,6– trimethoxybenzenesulfonamide (Mtb), 2,6–dimethyl–4–methoxybenzenesulfonamide (Pme), 2,3,5,6– tetramethyl–4–methoxybenzenesulfonamide (Mte), 4–methoxybenzenesulfonamide (Mbs), 2,4,6– trimethylbenzenesulfonamide (Mts), 2,6–dimethoxy–4–methylbenzenesulfonamide (iMds), 2,2,5,7,8– pentamethylchroman–6–sulfonamide (Pmc), methanesulfonamide (Ms), β–trimethylsilylethanesulfonamide (SES), 9–anthracenesulfonamide, 4–(4’,8’–dimethoxynaphthylmethyl)benzenesulfonamide (DNMBS), benzylsulfonamide, trifluoromethylsulfonamide, and phenacylsulfonamide.

[0084] Suitably protected carboxylic acids further include, but are not limited to, silyl–, alkyl–, alkenyl– , aryl–, and arylalkyl–protected carboxylic acids. Examples of suitable silyl groups include trimethylsilyl, triethylsilyl, t–butyldimethylsilyl, t–butyldiphenylsilyl, triisopropylsilyl, and the like. Examples of suitable alkyl groups include methyl, benzyl, p–methoxybenzyl, 3,4–dimethoxybenzyl, trityl, t–butyl, tetrahydropyran– 2–yl. Examples of suitable alkenyl groups include allyl. Examples of suitable aryl groups include optionally substituted phenyl, biphenyl, or naphthyl. Examples of suitable arylalkyl groups include optionally substituted benzyl (e.g., p–methoxybenzyl (MPM), 3,4–dimethoxybenzyl, O–nitrobenzyl, p–nitrobenzyl, p–halobenzyl, 2,6–dichlorobenzyl, p–cyanobenzyl), and 2– and 4–picolyl.

[0085] Suitable hydroxyl protecting groups include methyl, methoxylmethyl (MOM), methylthiomethyl (MTM), t–butylthiomethyl, (phenyldimethylsilyl)methoxymethyl (SMOM), benzyloxymethyl (BOM), p– methoxybenzyloxymethyl (PMBM), (4–methoxyphenoxy)methyl (p–AOM), guaiacolmethyl (GUM), t–butoxymethyl, 4–pentenyloxymethyl (POM), siloxymethyl, 2–methoxyethoxymethyl (MEM), 2,2,2– trichloroethoxymethyl, bis(2–chloroethoxy)methyl, 2–(trimethylsilyl)ethoxymethyl (SEMOR), tetrahydropyranyl (THP), 3–bromotetrahydropyranyl, tetrahydrothiopyranyl, 1–methoxycyclohexyl, 4– methoxytetrahydropyranyl (MTHP), 4–methoxytetrahydrothiopyranyl, 4–methoxytetrahydrothiopyranyl S,S– dioxide, 1–[(2–chloro–4–methyl)phenyl]–4–methoxypiperidin–4–yl (CTMP), 1,4–dioxan–2–yl, tetrahydrofuranyl, tetrahydrothiofuranyl, 2,3,3a,4,5,6,7,7a–octahydro–7,8,8–trimethyl–4,7– methanobenzofuran–2–yl, 1–ethoxyethyl, 1–(2–chloroethoxy)ethyl, 1–methyl–1–methoxyethyl, 1–methyl–1– benzyloxyethyl, 1–methyl–1–benzyloxy–2–fluoroethyl, 2,2,2–trichloroethyl, 2–trimethylsilylethyl, 2– (phenylselenyl)ethyl, t–butyl, allyl, p–chlorophenyl, p–methoxyphenyl, 2,4–dinitrophenyl, benzyl, p– methoxybenzyl, 3,4–dimethoxybenzyl, o–nitrobenzyl, p–nitrobenzyl, p–halobenzyl, 2,6–dichlorobenzyl, p– cyanobenzyl, p–phenylbenzyl, 2–picolyl, 4–picolyl, 3–methyl–2–picolyl N–oxido, diphenylmethyl, p,p’– dinitrobenzhydryl, 5–dibenzosuberyl, triphenylmethyl, α–naphthyldiphenylmethyl, p– methoxyphenyldiphenylmethyl, di(p–methoxyphenyl)phenylmethyl, tri(p–methoxyphenyl)methyl, 4–(4’– bromophenacyloxyphenyl)diphenylmethyl, 4,4’,4’’–tris(4,5–dichlorophthalimidophenyl)methyl, 4,4’,4’’– tris(levulinoyloxyphenyl)methyl, 4,4’,4’’–tris(benzoyloxyphenyl)methyl, 3–(imidazol–1–yl)bis(4’,4’’– dimethoxyphenyl)methyl, 1,1–bis(4–methoxyphenyl)–1’–pyrenylmethyl, 9–anthryl, 9–(9–phenyl)xanthenyl, 9–(9–phenyl–10–oxo)anthryl, 1,3–benzodithiolan–2–yl, benzisothiazolyl S,S–dioxido, trimethylsilyl (TMS), triethylsilyl (TES), triisopropylsilyl (TIPS), dimethylisopropylsilyl (IPDMS), diethylisopropylsilyl (DEIPS), dimethylthexylsilyl, t–butyldimethylsilyl (TBDMS), t–butyldiphenylsilyl (TBDPS), tribenzylsilyl, tri–p– xylylsilyl, triphenylsilyl, diphenylmethylsilyl (DPMS), t–butylmethoxyphenylsilyl (TBMPS), formate, benzoylformate, acetate, chloroacetate, dichloroacetate, trichloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, phenoxyacetate, p–chlorophenoxyacetate, 3–phenylpropionate, 4–oxopentanoate (levulinate), 4,4–(ethylenedithio)pentanoate (levulinoyldithioacetal), pivaloate, adamantoate, crotonate, 4– methoxycrotonate, benzoate, p–phenylbenzoate, 2,4,6–trimethylbenzoate (mesitoate), alkyl methyl carbonate, 9–fluorenylmethyl carbonate (Fmoc), alkyl ethyl carbonate, alkyl 2,2,2–trichloroethyl carbonate (Troc), 2– (trimethylsilyl)ethyl carbonate (TMSEC), 2–(phenylsulfonyl) ethyl carbonate (Psec), 2–(triphenylphosphonio) ethyl carbonate (Peoc), alkyl isobutyl carbonate, alkyl vinyl carbonate alkyl allyl carbonate, alkyl p– nitrophenyl carbonate, alkyl benzyl carbonate, alkyl p–methoxybenzyl carbonate, alkyl 3,4–dimethoxybenzyl carbonate, alkyl o–nitrobenzyl carbonate, alkyl p–nitrobenzyl carbonate, alkyl S–benzyl thiocarbonate, 4– ethoxy–1–napththyl carbonate, methyl dithiocarbonate, 2–iodobenzoate, 4–azidobutyrate, 4–nitro–4– methylpentanoate, o–(dibromomethyl)benzoate, 2–formylbenzenesulfonate, 2–(methylthiomethoxy)ethyl, 4– (methylthiomethoxy)butyrate, 2–(methylthiomethoxymethyl)benzoate, 2,6–dichloro–4– methylphenoxyacetate, 2,6–dichloro–4–(1,1,3,3–tetramethylbutyl)phenoxyacetate, 2,4–bis(1,1– dimethylpropyl)phenoxyacetate, chlorodiphenylacetate, isobutyrate, monosuccinoate, (E)–2–methyl–2– butenoate, o–(methoxycarbonyl)benzoate, α–naphthoate, nitrate, alkyl N,N,N’,N’– tetramethylphosphorodiamidate, alkyl N–phenylcarbamate, borate, dimethylphosphinothioyl, alkyl 2,4–dinitrophenylsulfenate, sulfate, methanesulfonate (mesylate), benzylsulfonate, and tosylate (Ts). For protecting 1,2– or 1,3–diols, the protecting groups include methylene acetal, ethylidene acetal, 1–t– butylethylidene ketal, 1–phenylethylidene ketal, (4–methoxyphenyl)ethylidene acetal, 2,2,2– trichloroethylidene acetal, acetonide, cyclopentylidene ketal, cyclohexylidene ketal, cycloheptylidene ketal, benzylidene acetal, p–methoxybenzylidene acetal, 2,4–dimethoxybenzylidene ketal, 3,4– dimethoxybenzylidene acetal, 2–nitrobenzylidene acetal, methoxymethylene acetal, ethoxymethylene acetal, dimethoxymethylene ortho ester, 1–methoxyethylidene ortho ester, 1–ethoxyethylidine ortho ester, 1,2– dimethoxyethylidene ortho ester, α–methoxybenzylidene ortho ester, 1–(N,N–dimethylamino)ethylidene derivative, α–(N,N’–dimethylamino)benzylidene derivative, 2–oxacyclopentylidene ortho ester, di–t– butylsilylene group (DTBS), 1,3–(1,1,3,3–tetraisopropyldisiloxanylidene) derivative (TIPDS), tetra–t– butoxydisiloxane–1,3–diylidene derivative (TBDS), cyclic carbonates, cyclic boronates, ethyl boronate, and phenyl boronate.

[0086] In some embodiments, a hydroxyl protecting group is acetyl, t-butyl, tbutoxymethyl, methoxymethyl, tetrahydropyranyl, 1 -ethoxyethyl, 1 -(2-chloroethoxy)ethyl, 2- trimethylsilylethyl, p- chlorophenyl, 2,4-dinitrophenyl, benzyl, benzoyl, p-phenylbenzoyl, 2,6- dichlorobenzyl, diphenylmethyl, p- nitrobenzyl, triphenylmethyl (trityl), 4,4'-dimethoxytrityl, trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t- butyldiphenylsilyl, triphenylsilyl, triisopropylsilyl, benzoylformate, chloroacetyl, trichloroacetyl, trifiuoroacetyl, pivaloyl, 9- fluorenylmethyl carbonate, mesylate, tosylate, triflate, trityl, monomethoxytrityl (MMTr), 4,4'-dimethoxytrityl, (DMTr) and 4,4',4''-trimethoxytrityl (TMTr), 2-cyanoethyl (CE or Cne), 2- (trimethylsilyl)ethyl (TSE), 2-(2-nitrophenyl)ethyl, 2-(4-cyanophenyl)ethyl 2-(4-nitrophenyl)ethyl (NPE), 2- (4-nitrophenylsulfonyl)ethyl, 3,5-dichlorophenyl, 2,4-dimethylphenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4,6- trimethylphenyl, 2-(2-nitrophenyl)ethyl, butylthiocarbonyl, 4,4',4''-tris(benzoyloxy)trityl, diphenylcarbamoyl, levulinyl, 2-(dibromomethyl)benzoyl (Dbmb), 2-(isopropylthiomethoxymethyl)benzoyl (Ptmt), 9- phenylxanthen-9-yl (pixyl) or 9-(p-methoxyphenyl)xanthine-9-y1 (MOX). In some embodiments, each of the hydroxyl protecting groups is, independently selected from acetyl, benzyl, t- butyldimethylsilyl, t- butyldiphenylsilyl and 4,4'-dimethoxytrityl. In some embodiments, the hydroxyl protecting group is selected from the group consisting of trityl, monomethoxytrityl and 4,4'-dimethoxytrityl group. In some embodiments, a phosphorous linkage protecting group is a group attached to the phosphorous linkage (e.g., an internucleotidic linkage) throughout oligonucleotide synthesis. In some embodiments, a protecting group is attached to a sulfur atom of an phosphorothioate group. In some embodiments, a protecting group is attached to an oxygen atom of an internucleotide phosphorothioate linkage. In some embodiments, a protecting group is attached to an oxygen atom of the internucleotide phosphate linkage. In some embodiments a protecting group is 2- cyanoethyl (CE or Cne), 2-trimethylsilylethyl, 2-nitroethyl, 2-sulfonylethyl, methyl, benzyl, o-nitrobenzyl, 2- (p-nitrophenyl)ethyl (NPE or Npe), 2-phenylethyl, 3-(N-tert-butylcarboxamido)-1-propyl, 4-oxopentyl, 4- methylthio-l-butyl, 2-cyano-1,1-dimethylethyl, 4-N-methylaminobutyl, 3-(2-pyridyl)-1-propyl, 2-[N-methyl- N-(2-pyridyl)]aminoethyl, 2-(N-formyl,N-methyl)aminoethyl, or 4-[N-methyl-N-(2,2,2-trifluoroacetyl)amino]butyl.

[0087] Subject: As used herein, the term “subject” or “test subject” refers to any organism to which a compound (e.g., an oligonucleotide) or composition is administered in accordance with the present disclosure e.g., for experimental, diagnostic, prophylactic and / or therapeutic purposes. Typical subjects include animals (e.g., mammals such as mice, rats, rabbits, non-human primates, and humans; insects; worms; etc.) and plants. In some embodiments, a subject is a human. In some embodiments, a subject may be suffering from and / or susceptible to a disease, disorder and / or condition.

[0088] Substantially: As used herein, the term “substantially” refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest. A base sequence which is substantially identical or complementary to a second sequence is not fully identical or complementary to the second sequence, but is mostly or nearly identical or complementary to the second sequence. In some embodiments, an oligonucleotide with a substantially complementary sequence to another oligonucleotide or nucleic acid forms duplex with the oligonucleotide or nucleic acid in a similar fashion as an oligonucleotide with a fully complementary sequence. In addition, one of ordinary skill in the biological and / or chemical arts will understand that biological and chemical phenomena rarely, if ever, go to completion and / or proceed to completeness or achieve or avoid an absolute result. The term “substantially” is therefore used herein to capture the potential lack of completeness inherent in many biological and / or chemical phenomena.

[0089] Sugar: The term “sugar” refers to a monosaccharide or polysaccharide in closed and / or open form. In some embodiments, sugars are monosaccharides. In some embodiments, sugars are polysaccharides. Sugars include, but are not limited to, ribose, deoxyribose, pentofuranose, pentopyranose, and hexopyranose moieties. As used herein, the term “sugar” also encompasses structural analogs used in lieu of conventional sugar molecules, such as glycol, polymer of which forms the backbone of the nucleic acid analog, glycol nucleic acid (“GNA”), etc. As used herein, the term “sugar” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified sugars and nucleotide sugars. In some embodiments, a sugar is a RNA or DNA sugar (ribose or deoxyribose). In some embodiments, a sugar is a modified ribose or deoxyribose sugar, e.g., 2’-modified, 5’-modified, etc. As described herein, in some embodiments, when used in oligonucleotides and / or nucleic acids, modified sugars may provide one or more desired properties, activities, etc. In some embodiments, a sugar is optionally substituted ribose or deoxyribose. In some embodiments, a “sugar” refers to a sugar unit in an oligonucleotide or a nucleic acid.

[0090] Susceptible to: An individual who is “susceptible to” a disease, disorder and / or condition is one who has a higher risk of developing the disease, disorder and / or condition than does a member of the general public. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition is predisposed to have that disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition may not have been diagnosed with the disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition may exhibit symptoms of the disease, disorder and / or condition. In some embodiments, an individualwho is susceptible to a disease, disorder and / or condition may not exhibit symptoms of the disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder, and / or condition will develop the disease, disorder, and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder, and / or condition will not develop the disease, disorder, and / or condition.

[0091] Therapeutic agent: As used herein, the term “therapeutic agent” in general refers to any agent that elicits a desired effect (e.g., a desired biological, clinical, or pharmacological effect) when administered to a subject. In some embodiments, an agent is considered to be a therapeutic agent if it demonstrates a statistically significant effect across an appropriate population. In some embodiments, an appropriate population is a population of subjects suffering from and / or susceptible to a disease, disorder or condition. In some embodiments, an appropriate population is a population of model organisms. In some embodiments, an appropriate population may be defined by one or more criterion such as age group, gender, genetic background, preexisting clinical conditions, prior exposure to therapy. In some embodiments, a therapeutic agent is a substance that alleviates, ameliorates, relieves, inhibits, prevents, delays onset of, reduces severity of, and / or reduces incidence of one or more symptoms or features of a disease, disorder, and / or condition in a subject when administered to the subject in an effective amount. In some embodiments, a “therapeutic agent” is an agent that has been or is required to be approved by a government agency before it can be marketed for administration to humans. In some embodiments, a “therapeutic agent” is an agent for which a medical prescription is required for administration to humans. In some embodiments, a therapeutic agent is a provided compound, e.g., a provided oligonucleotide.

[0092] Therapeutically effective amount: As used herein, the term “therapeutically effective amount” means an amount of a substance (e.g., a therapeutic agent, composition, and / or formulation) that elicits a desired biological response when administered as part of a therapeutic regimen. In some embodiments, a therapeutically effective amount of a substance is an amount that is sufficient, when administered to a subject suffering from or susceptible to a disease, disorder, and / or condition, to treat, diagnose, prevent, and / or delay the onset of the disease, disorder, and / or condition. As will be appreciated by those of ordinary skill in this art, the effective amount of a substance may vary depending on such factors as the desired biological endpoint, the substance to be delivered, the target cell or tissue, etc. For example, the effective amount of compound in a formulation to treat a disease, disorder, and / or condition is the amount that alleviates, ameliorates, relieves, inhibits, prevents, delays onset of, reduces severity of and / or reduces incidence of one or more symptoms or features of the disease, disorder, and / or condition. In some embodiments, a therapeutically effective amount is administered in a single dose; in some embodiments, multiple unit doses are required to deliver a therapeutically effective amount.

[0093] Treat: As used herein, the term “treat,” “treatment,” or “treating” refers to any method used to partially or completely alleviate, ameliorate, relieve, inhibit, prevent, delay onset of, reduce severity of, and / or reduce incidence of one or more symptoms or features of a disease, disorder, and / or condition. Treatment may be administered to a subject who does not exhibit signs of a disease, disorder, and / or condition. In someembodiments, treatment may be administered to a subject who exhibits only early signs of the disease, disorder, and / or condition, for example for the purpose of decreasing the risk of developing pathology associated with the disease, disorder, and / or condition.

[0094] Unsaturated: The term "unsaturated," as used herein, means that a moiety has one or more units of unsaturation.

[0095] Wild-type: As used herein, the term “wild-type” has its art-understood meaning that refers to an entity having a structure and / or activity as found in nature in a “normal” (as contrasted with mutant, diseased, altered, etc.) state or context. Those of ordinary skill in the art will appreciate that wild type genes and polypeptides often exist in multiple different forms (e.g., alleles).

[0096] As those skilled in the art will appreciate, methods and compositions described herein relating to provided compounds (e.g., oligonucleotides) generally also apply to pharmaceutically acceptable salts of such compounds. Description of Certain Embodiments

[0097] Oligonucleotides are useful in various therapeutic, diagnostic, and research applications. Use of naturally occurring nucleic acids is limited, for example, by their susceptibility to endo- and exo-nucleases. As such, various synthetic counterparts have been developed to circumvent these shortcomings and / or to further improve various properties and activities. These include synthetic oligonucleotides that contain chemical modifications, e.g., base modifications, sugar modifications, backbone modifications, etc., which, among other things, render these molecules less susceptible to degradation and improve other properties and / or activities.

[0098] From a structural point of view, modifications to internucleotidic linkages can introduce chirality, and certain properties and activities may be affected by configurations of linkage phosphorus atoms of oligonucleotides. For example, binding affinity, sequence specific binding to complementary RNA, stability to nucleases, activities, delivery, pharmacokinetics, etc. can be affected by, inter alia, chirality of backbone linkage phosphorus atoms. Dystrophin

[0099] In some embodiments, the present disclosure provides technologies, e.g., oligonucleotides, compositions, methods, etc., related to the dystrophin (DMD) gene or a gene product thereof (e.g., a nucleic acid (e.g., DNA, RNA), a transcript (e.g., a DMD transcript), a protein encoded thereby (e.g., a DMD polypeptide), etc.).

[0100] In some embodiments, the present disclosure provides technologies, including oligonucleotides and compositions and methods of use thereof, for treatment of muscular dystrophy, including but not limited to, Duchenne Muscular Dystrophy (also abbreviated as DMD) and Becker Muscular Dystrophy (BMD). In some embodiments, DMD comprises one or more mutations. In some embodiments, such mutations areassociated with reduced biological functions of dystrophin protein in a subject suffering from or susceptible to muscular dystrophy.

[0101] In some embodiments, the DMD gene or a gene product thereof, or a variant or portion thereof, may be referred to as DMD, BMD, CMD3B, DXS142, DXS164, DXS206, DXS230, DXS239, DXS268, DXS269, DXS270, DXS272, MRX85, dystrophin, etc. Various DMD sequences including variants thereof are readily available to those of skill in the art, including those sequences associated with the following identification numbers: (i) for human: OMIM: 300377; GeneCards: DMD; Entrez ID: 1756; Ensembl: ENSG00000198947; UniProt: P11532; RefSeq (mRNA): NM_000109, NM_004006, NM_004007, NM_004009, and NM_004010; RefSeq (protein): NP_000100, NP_003997, NP_004000, NP_004001, and NP_004002; Location (UCSC): Chr X: 31.1 – 33.34 Mb; (ii) for mouse: MGI: 94909; Entrez ID: 13405; Ensembl: ENSMUSG00000045103; UniProt: P11531; RefSeq (mRNA): NM_007868, NM_001314034, NM_001314035, NM_001314036, and NM_001314037; RefSeq (protein): NP_001300963, NP_001300964, NP_001300965, NP_001300966, and NP_001300967; Location (UCSC): Chr X: 82.95 – 85.21 Mb; and (iii) for multiple species: HomoloGene: 20856.

[0102] The DMD gene reportedly contains 79 exons distributed over 2.3 million bp of genetic real estate on the X chromosome; however, only approximately 14,000 bp (<1%) is reported to be used for translation into protein (coding sequence). It is reported that about 99.5% of the genetic sequence, the intronic sequences, is spliced out of the 2.3 million bp initial heteronuclear RNA DMD transcript to provide a mature 14,000 bp mRNA which includes all key information for dystrophin protein production. In some embodiments, patients with DMD have mutation(s) in the DMD gene that prevent the appropriate construction of the wild-type DMD mRNA and / or the production of the wild-type dystrophin protein, and patients with DMD often show marked dystrophin deficiency in their muscle.

[0103] In some embodiments, a dystrophin DMD transcript, e.g., mRNA, or protein encompasses those related to or produced from alternative splicing. For example, sixteen alternative DMD transcripts of the dystrophin gene were reported following an analysis of splicing patterns of the DMD gene in skeletal muscle, brain and heart tissues (Sironi et al.2002 FEBS Letters 517: 163-166).

[0104] It is reported that dystrophin has several isoforms. In some embodiments, dystrophin refers to a specific isoform. At least three full-length dystrophin isoforms have been reported, each controlled by a tissue- specific promoter (Klamut et al. 1990 Mol. Cell. Biol. 10: 193-205; Nudel et al. 1989 Nature 337: 76-78; Gorecki et al. 1992 Hum. Mol. Genet. 1: 505-510). The muscle isoform is reportedly mainly expressed in skeletal muscle but also in smooth and cardiac muscles (Bies, R.D., Phelps, S.F., Cortez, M.D., Roberts, R., Caskey, C.T. and Chamberlain, J.S.1992 Nucleic Acids Res.20: 1725-1731), the brain dystrophin is reportedly specific for cortical neurons but can also be detected in heart and cerebellar neurons, while the Purkinje-cell type reportedly accounts for nearly all cerebellar dystrophin (Gorecki et al. 1992 Hum. Mol. Genet.1: 505- 510). Alternative splicing reportedly provides a means for dystrophin diversification: the 3’ region of the gene reportedly undergoes alternative splicing resulting in tissue-specific DMD transcripts in brain neurons, cardiacPurkinje fibers, and smooth muscle cells (Bies et al.1992 Nucleic Acids Res.20: 1725-1731; and Feener et al. 1989 Nature 338: 509-511) while 12 patterns of alternative splicing have been reported in the 5’ region of the gene in skeletal muscle (Surono et al. 1997 Biochem. Biophys. Res. Commun.239: 895-899).

[0105] In some embodiments, a dystrophin gene, transcript (e.g., mRNA), or protein is a revertant version. Among others, revertant dystrophins were reported in, for example: Hoffman et al.1990 J. Neurol. Sci.99:9- 25; Klein et al.1992 Am. J. Hum. Genet.50: 950-959; and Chelly et al.1990 Cell 63: 1239-1348; Arahata et al.1998 Nature 333: 861-863; Bonilla et al.1988 Cell 54: 447-452; Fanin et al.1992 Neur. Disord.2: 41-45; Nicholson et al. 1989 J. Neurol. Sci. 94: 137-146; Shimizu et al. 1988 Proc. Jpn. Acad. Sci. 64: 205-208; Sicinzki et al.1989 Science 244: 1578-1580; and Sherratt et al. Am. J. Hum. Genet.53: 1007-1015.

[0106] Various mutations in the DMD gene can and / or were reported to cause muscular dystrophy. The variety of mutations in the DMD gene are reviewed in, e.g., Flanigan et al. 2009 Hum Mutat. 30(12): 1657- 1666. Mutations in the form of large deletions (1 or more exons) are reported to account for approximately two-thirds of all DMD gene mutations; the remaining mutations are reported to be due to duplications and small deletions, insertions, point mutations, or splicing mutations. According to certain reports, deletions are typically clustered in a hotspot region between exons 45 and 55 and prevent translation of dystrophin. Absent or defective dystrophin protein, resulting from DMD gene mutations, is reported to disrupt the dystrophin- glycoprotein complex, leading to increased muscle membrane fragility, chronic muscle damage, inflammation, replacement of muscle fibers with fat and fibrotic tissue, and then loss of muscle function. Various databases of mutations in the DMD gene have been constructed, including those described in, e.g., Aartsma-Rus et al. 2006 Muscle Nerve. 34(2):135-44; Bladen et al. 2015 Hum Mutat. 36(4):395-402. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) comprises a deletion. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) comprises a point mutation. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) comprises an insertion. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) comprises a duplication. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) is a mutation amenable to exon skipping. In some embodiments, a mutation in a DMD gene or gene product thereof (e.g., a DMD transcript) is a mutation amenable to exon 45 skipping. Oligonucleotides

[0107] Among other things, the present disclosure provides oligonucleotides of various designs, which may comprise various nucleobases and patterns thereof, sugars and patterns thereof, internucleotidic linkages and patterns thereof, and / or additional chemical moieties and patterns thereof as described in the present disclosure.

[0108] In some embodiments, the present disclosure provides oligonucleotides and / or oligonucleotide compositions that are useful for various purposes, e.g., modulating skipping, reducing levels of DMD transcripts, improving levels of beneficial proteins, treating conditions, diseases and disorders, etc. In someembodiments, the present disclosure provides oligonucleotide compositions with improved properties, e.g., increased skipping of exon 45, reduced toxicities, etc. Among other things, oligonucleotides of the present disclosure comprise chemical modifications, stereochemistry, and / or combinations thereof which can improve various properties and activities of oligonucleotides. Non-limiting examples of oligonucleotides are listed in Table 1 (e.g., Table 1A, Table 1B, Table 1C). Base Sequences

[0109] As appreciated by those skilled in the art, structural features of the present disclosure, such as nucleobase modification, sugar modifications, internucleotidic linkage modifications, linkage phosphorus stereochemistry, etc., and combinations thereof may be utilized with various suitable base sequences to provide oligonucleotides and compositions with desired properties and / or activities.

[0110] In some embodiments, an oligonucleotide has a base sequence described herein (e.g., in a Table) or a portion thereof (e.g., a span of 10-50, 10-40, 10-30, 10-20, or 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least 10, at least 15, at least 20 contiguous nucleobases) with 0-5 (e.g., 0, 1, 2, 3, 4 or 5) mismatches, wherein each T can be independently substituted with U and vice versa. In some embodiments, an oligonucleotide comprises a base sequence described herein, or a portion thereof, wherein a portion is a span of at least 10 contiguous nucleobases, or a span of at least 15 contiguous nucleobases with 0-5 mismatches. In some embodiments, provided oligonucleotides have a base sequence described herein, or a portion thereof, wherein a portion is a span of at least 10 contiguous nucleobases, or a span of at least 10 contiguous nucleobases with 1-5 mismatches, wherein each T can be independently substituted with U and vice versa.

[0111] In some embodiments, base sequences of oligonucleotides comprise or consist of 10-60 (e.g., about or at least 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 45, 50, 55, 60; in some embodiments, at least 15; in some embodiments, at least 16; in some embodiments, at least 17; in some embodiments, at least 18; in some embodiments, at least 19; in some embodiments, at least 20; in some embodiments, at least 21; in some embodiments, at least 22; in some embodiments, at least 23; in some embodiments, at least 24; in some embodiments, at least 25; in some embodiments, at least 26; in some embodiments, at least 27; in some embodiments, at least 28; in some embodiments, at least 29; in some embodiments, at least 30; in some embodiments, at least 31; in some embodiments, at least 32; in some embodiments, at least 33; in some embodiments, at least 34; in some embodiments, at least 35) bases, optionally contiguous, of a base sequence that is identical or complementary to a base sequence of nucleic acid, e.g., a DMD gene or a transcript thereof. In some embodiments, the base sequence of an oligonucleotide is or comprises a sequence that is complementary to a target sequence in a gene or a transcript thereof.

[0112] In some embodiments, a target sequence is or comprises a characteristic sequence of a nucleic acid sequence (e.g., of an gene or a transcript thereof) in that it defines the nucleic acid sequence over others in a relevant organism; for example, a characteristic sequence is not in or has at least various mismatches fromother genomic nucleic acid sequences (e.g., genes) or transcripts thereof in a relevant organism. In some embodiments, a characteristic sequence of a transcript defines that transcript over other transcripts in a relevant organism; for example, in some embodiments, a characteristic sequence is not in transcripts that are transcribed from a different nucleic acid sequence (e.g., a different gene). In some embodiments, transcript variants from a nucleic acid sequence (e.g., mRNA variants of a gene) may share a common characteristic sequence that defines them from, e.g., transcripts of other genes.

[0113] Base sequences of provided oligonucleotides, as appreciated by those skilled in the art, typically have sufficient lengths and complementarity to their target nucleic acids, e.g., RNA transcripts (e.g., pre- mRNA, mature mRNA, etc.) for, e.g., exon skipping. As appreciated by those skilled in the art, in many instances target nucleic acids are longer than oligonucleotides of the present disclosure, and complementarity may be properly assessed based on the shorter of the two, oligonucleotides. In some embodiments, the base sequence of an oligonucleotide has 90% or more identity with the base sequence of an oligonucleotide disclosed in a Table, wherein each T can be independently substituted with U and vice versa. In some embodiments, the base sequence of an oligonucleotide has 95% or more identity with the base sequence of an oligonucleotide disclosed in a Table, wherein each T can be independently substituted with U and vice versa. In some embodiments, the base sequence of an oligonucleotide comprises a continuous span of 15, 16, 17, 18, 19, 20 or more bases of an oligonucleotide disclosed in a Table, wherein each T can be independently substituted with U and vice versa, except that one or more bases within the span are abasic (e.g., a nucleobase is absent from a nucleotide).

[0114] In some embodiments, the present disclosure pertains to an oligonucleotide having a base sequence which comprises the base sequence of any oligonucleotide disclosed herein, wherein each T may be independently replaced with U and vice versa.

[0115] In some embodiments, the present disclosure pertains to an oligonucleotide having a base sequence which is the base sequence of any oligonucleotide disclosed herein, wherein each T may be independently replaced with U and vice versa.

[0116] In some embodiments, the present disclosure pertains to an oligonucleotide having a base sequence which comprises at least 15 contiguous bases of the base sequence of any oligonucleotide disclosed herein, wherein each T may be independently replaced with U and vice versa.

[0117] In some embodiments, the present disclosure pertains to an oligonucleotide having a base sequence which is at least 90% identical to the base sequence of any oligonucleotide disclosed herein, wherein each T may be independently replaced with U and vice versa.

[0118] In some embodiments, the present disclosure pertains to an oligonucleotide having a base sequence which is at least 95% identical to the base sequence of any oligonucleotide disclosed herein, wherein each T may be independently replaced with U and vice versa.

[0119] In some embodiments, a base sequence of an oligonucleotide is, comprises, or comprises 10-40, e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 contiguousbases of the base sequence of any oligonucleotide described herein, wherein each T may be independently replaced with U and vice versa.

[0120] In some embodiments, an oligonucleotide is an oligonucleotide presented in a Table herein.

[0121] In some embodiments, the base sequence of an oligonucleotide is complementary to that of a target nucleic acid, e.g., a dystrophin gene or transcript thereof. In some embodiments, a base sequence of an oligonucleotide is at least about 50%, 60%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, or 100% complementary to a target sequence in a DMD transcript. In some embodiments, a base sequence of an oligonucleotide is fully complementary to a target sequence in a DMD transcript.

[0122] In some embodiments, an oligonucleotide has a base sequence which comprises at least 15 contiguous bases (e.g., 15, 16, 17, 18, 19, or 20) of an oligonucleotide in a Table, wherein each T can be independently substituted with U and vice versa.

[0123] In some embodiments, an oligonucleotide comprises a base sequence or portion thereof (e.g., a portion comprising 10-40, e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 nucleobases) described in any of the Tables, wherein each T may be independently replaced with U and vice versa, and / or a sugar, nucleobase, and / or internucleotidic linkage modification and / or stereochemistry, and / or a pattern thereof described in any of the Tables, and / or an additional chemical moiety (in addition to an oligonucleotide chain, e.g., a target moiety, a lipid moiety, a carbohydrate moiety, etc.) described in any of the Tables.

[0124] In some embodiments, the terms “complementary,” “fully complementary” and “substantially complementary” may be used with respect to the base matching between an oligonucleotide and a target sequence, as will be understood by those skilled in the art from the context of their uses. It is noted that substitution of T for U, or vice versa, generally does not alter the amount of complementarity. As used herein, an oligonucleotide that is “substantially complementary” to a target sequence is largely or mostly complementary but not necessarily 100% complementary. In some embodiments, a sequence (e.g., an oligonucleotide ) which is substantially complementary has one or more, e.g., 1, 2, 3, 4 or 5 mismatches when maximally aligned to its target sequence. In some embodiments, an oligonucleotide has a base sequence which is substantially complementary to a target sequence of a target nucleic acid. In some embodiments, an oligonucleotide has a base sequence which is substantially complementary to the complement of the sequence of an oligonucleotide disclosed herein. As appreciated by those skilled in the art, in some embodiments, sequences of oligonucleotides need not be 100% complementary to their targets for oligonucleotides to perform their functions. In some embodiments, base sequences of provided oligonucleotides are fully complementary to their target sequences (A-T / U and C-G base pairing).

[0125] In some embodiments, an oligonucleotide comprises an oligonucleotide comprises a sequence that is complementary to a characteristic portion of a nucleic acid. In some embodiments, an oligonucleotide comprises a sequence that is complementary to a characteristic portion of a DMD transcript. In some embodiments, the base sequence of an oligonucleotide is complementary to a characteristic portion of a nucleicacid. In some embodiments, the base sequence of an oligonucleotide is complementary to a characteristic portion of a DMD transcript. In some embodiments, a characteristic portion is a characteristic sequence. In some embodiments, a characteristic sequence of a DMD transcript is or comprises a complementary sequence of the sequence of an oligonucleotide in Table 1 (e.g., Table 1A, Table 1B, Table 1C). In some embodiments a characteristic sequence is or comprises GGCUUCAACUAUCUGAGUGA, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises CGGCAAACUGUUGUCAGAAC, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises GCGGCAAACUGUUGUCAGAA, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises AGCGGCAAACUGUUGUCAGA, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises CAGCGGCAAACUGUUGUCAG, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises GGCAUUGGGCAGCGGCAAAC, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises CUCCAGGAUGGCAUUGGGCA, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises GAACUCCAGGAUGGCAUUGG, wherein each U may be independently replaced with T. In some embodiments a characteristic sequence is or comprises CAGGAACUCCAGGAUGGCAU, wherein each U may be independently replaced with T.

[0126] In some embodiments, an oligonucleotide can hybridize to a region of a nucleic acid. In some embodiments, a region has a length of about 20-200 (e.g., about 20-150, 20-100, 30-200, 30-150, 40-200, 40- 150, 50-100, or about 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 or 200) nucleobases. In some embodiments, a region has a length of about 30 nucleobases. In some embodiments, a region has a length of about 40 nucleobases. In some embodiments, a region has a length of about 50 nucleobases. In some embodiments, a region has a length of about 60 nucleobases. In some embodiments, a region has a length of about 70 nucleobases. In some embodiments, a region has a length of about 80 nucleobases. In some embodiments, a region has a length of about 90 nucleobases. In some embodiments, a region has a length of about 100 nucleobases. In some embodiments, a region has a length of about 120 nucleobases. In some embodiments, a region has a length of about 150 nucleobases. In some embodiments, a region has a length of about 200 nucleobases. In some embodiments, a region comprises a complementary sequence of a base sequence of an oligonucleotide in Table 1 (e.g., Table 1A, Table 1B, Table 1C), which in some embodiments, is in the middle of a region. For example, in some embodiments, a region is or comprises GGCUUCAACUAUCUGAGUGA. In some embodiments, a region is or comprisesGGCAUUGGGCAGCGGCAAAC. In some embodiments, a region is or comprises CUCCAGGAUGGCAUUGGGCA. In some embodiments, a region is or comprises GAACUCCAGGAUGGCAUUGG. In some embodiments, a region is or comprises CAGGAACUCCAGGAUGGCAU.

[0127] In some embodiments, the present disclosure provides an oligonucleotide comprising a sequence found in an oligonucleotide described in a Table, wherein one or more U is independently and optionally replaced with T or vice versa. In some embodiments, an oligonucleotide can comprise at least one T and / or at least one U. In some embodiments, the present disclosure provides an oligonucleotide comprising a sequence found in an oligonucleotide described in a Table herein, wherein the said sequence has over 50% identity with the sequence of the oligonucleotide described in a Table. In some embodiments, the present disclosure provides an oligonucleotide whose base sequence is the sequence of an oligonucleotide disclosed in a Table, wherein each T may be independently replaced with U and vice versa. In some embodiments, the present disclosure provides an oligonucleotide comprising a sequence found in an oligonucleotide in a Table, wherein the oligonucleotides have a pattern of backbone linkages, pattern of backbone chiral centers, and / or pattern of backbone phosphorus modifications of the same oligonucleotide or another oligonucleotide in a Table herein.

[0128] In some embodiments, the disclosure provides an oligonucleotide having a base sequence which is, comprises, or comprises a portion of the base sequence of an oligonucleotide disclosed herein, e.g., in a Table, wherein each T may be independently replaced with U and vice versa, wherein the oligonucleotide optionally further comprises a chemical modification, stereochemistry, format, an additional chemical moiety described herein (e.g., a targeting moiety, lipid moiety, carbohydrate moiety, etc.), and / or another structural feature.

[0129] In some embodiments, a “portion” (e.g., of a base sequence or a pattern of modifications or other structural element) is at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 monomeric units long.

[0130] As examples, certain oligonucleotides comprising certain example base sequences, nucleobase modifications and patterns thereof, sugar modifications and patterns thereof, internucleotidic linkages and patterns thereof, linkage phosphorus stereochemistry and patterns thereof, linkers, and / or additional chemical moieties, etc., are presented in Table 1, below. Among other things, these oligonucleotides may be utilized for exon skipping. In some embodiments, listed in Tables are stereorandom oligonucleotide compositions. In some embodiments, the present disclosure provides chirally controlled oligonucleotide compositions.

[0131] In some embodiments, a base sequence is or comprises a particular sequence. In some embodiments, a base sequence is complementary to a base sequence that is or comprises a base sequence that is complementary to a particular sequence. In some embodiments, a base sequence is or comprise a sequence that differs from a particular sequence at no more than 1, 2, 3, 4, or 5 positions. In some embodiments, a base sequence is or comprise a sequence that differs from about 15-30 (e.g., 15-25, 15-20, 20-30, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30) consecutive nucleobases of a particular sequence at no more than 1, 2, 3, 4, or 5 positions. In some embodiments, a base sequence is or comprise a sequence that differs from aparticular sequence at no more than 1 position. In some embodiments, a base sequence is or comprise a sequence that differs from a particular sequence at no more than 2 positions. In some embodiments, a base sequence is or comprise a sequence that differs from a particular sequence at no more than 3 positions. In some embodiments, a base sequence is or comprise a sequence that differs from a particular sequence at no more than 4 positions. In some embodiments, a base sequence is or comprise a sequence that differs from a particular sequence at no more than 5 positions. In some embodiments, a particular sequence is or comprises a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 5-20, 10- 20, or 15-20 (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 10 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 11 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 12 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 13 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 14 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 15 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 16 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 17 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 18 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 19 consecutive bases in a base sequence selected from Table 1. In some embodiments, a particular sequence is or comprises 20 consecutive bases in a base sequence selected from Table 1. In some embodiments, a base sequence selected from Table 1 is a base sequence selected from Table 1A. In some embodiments, a base sequence selected from Table 1 is a base sequence selected from Table 1B. In some embodiments, a base sequence selected from Table 1 is a base sequence selected from Table 1C. In some embodiments, a particular sequence is or comprises UCACUCAGAUAGUUGAAGCC, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises UCACUCAGAUAGUUGAAGCC. In some embodiments, a particular sequence is or comprises GUUCUGACAACAGUUUGCCG, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises GUUCUGACAACAGUUUGCCG. In some embodiments, a particular sequence is or comprises UUCUGACAACAGUUUGCCGC, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises UUCUGACAACAGUUUGCCGC. In some embodiments, a particular sequence is or comprises UCUGACAACAGUUUGCCGCU, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises UCUGACAACAGUUUGCCGCU. In some embodiments, a particular sequence is or comprises CUGACAACAGUUUGCCGCUG, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprisesCUGACAACAGUUUGCCGCUG. In some embodiments, a particular sequence is or comprises GUUUGCCGCUGCCCAAUGCC, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises GUUUGCCGCUGCCCAAUGCC. In some embodiments, a particular sequence is or comprises UGCCCAAUGCCAUCCUGGAG, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises UGCCCAAUGCCAUCCUGGAG. In some embodiments, a particular sequence is or comprises CCAAUGCCAUCCUGGAGUUC, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises CCAAUGCCAUCCUGGAGUUC. In some embodiments, a particular sequence is or comprises AUGCCAUCCUGGAGUUCCUG, wherein each U can be independently replaced with T and vice versa. In some embodiments, a particular sequence is or comprises AUGCCAUCCUGGAGUUCCUG.Notes: HELM Description and Base Sequence, due to their length, may be divided into multiple lines in Table 1 (e.g., Table 1A, Table 1B, Table 1C). Unless otherwise specified, all oligonucleotides in Table 1 are single- stranded. As appreciated by those skilled in the art, nucleoside units are unmodified and contain unmodified nucleobases and 2’-deoxy sugars unless otherwise indicated (e.g., with m, [fl2r], etc.); linkages, unless otherwise indicated, are natural phosphate linkages; and acidic / basic groups may independently exist in their salt forms. If a sugar is not specified, the sugar is a natural DNA sugar; and if an internucleotidic linkage is not specified, the internucleotidic linkage is a natural phosphate linkage. A natural DNA sugar may also be indicated with “d” as in d(G), d(A), d(C), d(T), etc., and a natural phosphate linkage may be indicated with “p” in Table 1. Oligonucleotides in Table 1 (e.g., Table 1A, Table 1B, Table 1C) are described using the Hierarchical Editing Language for Macromolecules (HELM), which is described in, e.g., Zhang, T. et al. J Chem Inf Model.2012 Oct 22;52(10):2796-806 and Milton, J. et al. J Chem Inf Model.2017 Jun 26;57(6):1233-1239. Moieties and modifications: m: 2’-OMe (e.g., m(G), m(A), m(C), m(U)); [m5C]: methyl at 5-position of C (nucleobase is 5-methylcytosine); [fl2r]: 2’-F; r: 2’-OH ( [moe]: 2'-[moe]([m5C]): 5-methyl 2’-O-methoxyethyl C; p: phosphodiester (phosphate). It can a linkage or be an end group (or a component thereof), e.g., a linkage between a linker and an oligonucleotide chain, an internucleotidic linkage (a natural phosphate linkage), etc.; *: Phosphorothioate. It can be an end group (or a component thereof), or a linkage, e.g., a linkage between a linker and an oligonucleotide chain, an internucleotidic linkage (a phosphorothioate internucleotidic linkage), etc.; [Rsp]: Phosphorothioate in the Rp configuration; [Ssp]: Phosphorothioate in the Sp configuration; [sp]: stereorandom phosphorothioate; n[n001]: stereorandom n001; [n001R]: n001 in Rp configuration; [n001S]: n001 in Sp configuration. In some embodiments, a sugar is bonded to an internucleotidic linkage through an oxygen atom, e.g., an oxygenatom in a natural phosphate linkage such as in typical natural DNA molecules. In some embodiments, a sugar is boned to an internucleotidic linkage through an atom that is not oxygen. In some embodiments, a sugar is boned to an internucleotidic linkage through a nitrogen atom of a sugar. In some embodiments, a sugar is boned to an internucleotidic linkage through a ring nitrogen atom of a sugar; in such cases, a ring nitrogen atom of a sugar may directly form a bond with a linkage phosphorus atom, and those skilled in the art will appreciate an oxygen atom may be removed from a linkage. Certain reagents (e.g., phosphoramidites, nucleosides, etc.) and methods for utilizing various modifications, e.g., those exemplified in the Tables herein, such as modified sugars, modified nucleobases, etc., are described in the Examples, WO 2021 / 071858 or WO 2022 / 099159, each of which is incorporated herein by reference. As those skilled in the art appreciate, an oligonucleotide may be referred to by its HELM description, e.g., in the Tables above, with or without “RNA1{}$$$$V2.0”.

[0132] Structures of certain oligonucleotides are illustrated herein. In some embodiments, an oligonucleotide is provided in a composition, e.g., a pharmaceutical composition. In some embodiments, an oligonucleotide is administered in a pharmaceutically acceptable salt form. In some embodiments, an oligonucleotide is administered in two or more pharmaceutically acceptable salt forms. In some embodiments, the present disclosure provides pharmaceutically acceptable salts of oligonucleotides provided herein, e.g., ASO-0141073, ASO-0141075, etc. in pharmaceutically acceptable salt forms. In some embodiments, a pharmaceutically acceptable salt is a sodium salt. In some embodiments, the present disclosure provides ASO- 0141073 as a pentadecasodium salt. In some embodiments, the present disclosure provides ASO-0141075 as a pentadecasodium salt.

[0133] Those skilled in the art can calculate various properties of provided oligonucleotides, e.g., molecular weights. For example, molecular formulae and molecular weights of ASO-0141073 acid and pentadecasodium salt forms are described below: Molecular Formula (free acid form): C213H263F16N84O107P19S13Molecular Weight (free acid form): 7021.18 g / mol Molecular Formula (pentadecasodium salt form): C213H248F16N84Na15O107P19S13Molecular Weight (pentadecasodium salt form): 7350.91 g / mol

[0134] In some embodiments, the present disclosure provides a compound, wherein the compound is a compound of formula A or a salt thereof. In some embodiments, a salt is a pharmaceutically acceptable salt. In some embodiments, a salt is a sodium salt. In some embodiments, a salt is a compound of formula A-i. In some embodiments, an oligonucleotide is a compound of formula A or a salt thereof. In some embodiments, the structure of ASO-0141073 in its free acid form may be depicted as Formula A below. In some embodiments, the structure of ASO-0141073 pentadecasodium salt form may be depicted as Formula A-i below. In some embodiments, diastereomeric purity of each chiral linkage phosphorus in a compound of formula A or a salt thereof is independently as described herein, e.g., about or at least about 95% (about 95%- 100%), about or at least about 97% (about 97%-100%), etc. In some embodiments, diastereomeric purity orpurity of a compound of formula A or a salt thereof is independently as described herein, e.g., for diastereomeric purity, about (DS)nc, wherein each of DS and nc is independently as described herein (e.g., DS being at least about 95% (about 95%-100%), about or at least about 97% (about 97%-100%), etc.) In some embodiments, a composition or preparation of ASO-0141073 comprises a compound of formula A or a salt thereof. In some embodiments, a composition or preparation of ASO-0141073 comprises a compound of formula A or a pharmaceutically acceptable salt thereof. In some embodiments, a composition or preparation of ASO-0141073 comprises a compound of formula A-i. In some embodiments, a composition or preparation of ASO-0141073 comprises two pharmaceutically acceptable salts of a compound of formula A. In some embodiments, a composition or preparation is a pharmaceutical composition.

[0135] Molecular formulae and molecular weights of ASO-0141075 acid and pentadecasodium salt forms are described below: Molecular Formula (free acid form): C213H264F16N85O106P19S13 Molecular Weight (free acid form): 7020.20 g / mol Molecular Formula (pentadecasodium salt form): C213H249F16N85Na15O106P19S13Molecular Weight (pentadecasodium salt form): 7349.93 g / mol

[0136] In some embodiments, the present disclosure provides a compound, wherein the compound is a compound of formula B or a salt thereof. In some embodiments, a salt is a pharmaceutically acceptable salt. In some embodiments, a salt is a sodium salt. In some embodiments, a salt is a compound of formula B-i. In some embodiments, an oligonucleotide is a compound of formula A or a salt thereof. In some embodiments, the structure of ASO-0141075 in its free acid form may be depicted as Formula B below. In some embodiments, the structure of ASO-0141075 pentadecasodium salt form may be depicted as Formula B-i below. In some embodiments, diastereomeric purity of each chiral linkage phosphorus in a compound of formula B or a salt thereof is independently as described herein, e.g., about or at least about 95% (about 95%- 100%), about or at least about 97% (about 97%-100%), etc. In some embodiments, diastereomeric purity or purity of a compound of formula B or a salt thereof is independently as described herein, e.g., for diastereomeric purity, about (DS)nc, wherein each of DS and nc is independently as described herein (e.g., DS being at least about 95% (about 95%-100%), about or at least about 97% (about 97%-100%), etc.) In some embodiments, a composition or preparation of ASO-0141075 comprises a compound of formula B or a salt thereof. In some embodiments, a composition or preparation of ASO-0141075 comprises a compound of formula B or a pharmaceutically acceptable salt thereof. In some embodiments, a composition or preparation of ASO-0141075 comprises a compound of formula B-i. In some embodiments, a composition or preparation of ASO-0141075 comprises two pharmaceutically acceptable salts of a compound of formula B. In some embodiments, a composition or preparation is a pharmaceutical composition.Formula AFormula BFormula B-i

[0137] In Formulas A, A-i, B, and B-i, due to the sizes of the structures, the structures are presented in multiple rows. As shown in these Formulae, each linkage in ASO-0141073 or ASO-0141075 is independently a Sp phosphorothioate linkage, a Rp n001 linkage, or a natural phosphate linkage, and in an ASO-0141073 salt or ASO-0141075 salt, acidic hydrogen atoms of the phosphorothioate and phosphate linkages may beindependently replaced with cations, e.g., in a pentadecasodium salt, each replaced with sodium. Nucleobases

[0138] Various nucleobases may be utilized in provided oligonucleotides in accordance with the present disclosure. In some embodiments, a nucleobase is a natural nucleobase, the most commonly occurring ones being A, T, C, G and U. In some embodiments, a nucleobase is a modified nucleobase in that it is not A, T, C, G or U. In some embodiments, a nucleobase is optionally substituted A, T, C, G or U, or a substituted tautomer of A T, C, G or U. In some embodiments, a nucleobase is optionally substituted A, T, C, G or U, e.g., 5mC, 5-hydroxymethyl C, etc. In some embodiments, a nucleobase is alkyl-substituted A, T, C, G or U. In some embodiments, a nucleobase is A. In some embodiments, a nucleobase is T. In some embodiments, a nucleobase is C. In some embodiments, a nucleobase is G. In some embodiments, a nucleobase is U. In some embodiments, a nucleobase is 5mC. In some embodiments, a nucleobase is substituted A, T, C, G or U. In some embodiments, a nucleobase is a substituted tautomer of A, T, C, G or U. In some embodiments, substitution protects certain functional groups in nucleobases to minimize undesired reactions during oligonucleotide synthesis. Suitable technologies for nucleobase protection in oligonucleotide synthesis are widely known in the art and may be utilized in accordance with the present disclosure. In some embodiments, modified nucleobases improves properties and / or activities of oligonucleotides. For example, in many cases, 5mC may be utilized in place of C to modulate certain undesired biological effects, e.g., immune responses. In some embodiments, when determining sequence identity, a substituted nucleobase having the same hydrogen-bonding pattern is treated as the same as the unsubstituted nucleobase, e.g., 5mC may be treated the same as C [e.g., an oligonucleotide having 5mC in place of C (e.g., AT5mCG) is considered to have the same base sequence as an oligonucleotide having C at the corresponding location(s) (e.g., ATCG)]. In some embodiments, a nucleobase is or comprise an optionally substituted ring having at least one nitrogen atom. In some embodiments, a nucleobase comprise Ring BA as described herein, wherein at least one monocyclic ring of Ring BA comprise a nitrogen ring atom.

[0139] In some embodiments, an oligonucleotide comprises one or more A, T, C, G or U. In some embodiments, an oligonucleotide comprises one or more optionally substituted A, T, C, G or U. In some embodiments, an oligonucleotide comprises one or more 5-methylcytidine, 5-hydroxymethylcytidine, 5- formylcytosine, or 5-carboxylcytosine. In some embodiments, an oligonucleotide comprises one or more 5- methylcytidine. In some embodiments, each nucleobase in an oligonucleotide is selected from the group consisting of optionally substituted A, T, C, G and U, and optionally substituted tautomers of A, T, C, G and U. In some embodiments, each nucleobase in an oligonucleotide is optionally protected A, T, C, G and U. In some embodiments, each nucleobase in an oligonucleotide is optionally substituted A, T, C, G or U. In some embodiments, each nucleobase in an oligonucleotide is selected from the group consisting of A, T, C, G, U, and 5mC.

[0140] As appreciated by those skilled in the art, various nucleobases are known in the art and can beutilized in accordance with the present disclosure, e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the sugar, base, and internucleotidic linkage modifications of each of which are independently incorporated herein by reference. In some embodiments, nucleobases are protected and useful for oligonucleotide synthesis.

[0141] In some embodiments, a nucleobase is a natural nucleobase or a modified nucleobase derived from a natural nucleobase. Examples include uracil, thymine, adenine, cytosine, and guanine optionally having their respective amino groups protected by acyl protecting groups, 2-fluorouracil, 2-fluorocytosine, 5-bromouracil, 5-iodouracil, 2,6-diaminopurine, azacytosine, pyrimidine analogs such as pseudoisocytosine and pseudouracil and other modified nucleobases such as 8-substituted purines, xanthine, or hypoxanthine (the latter two being the natural degradation products). Certain examples of modified nucleobases are disclosed in Chiu and Rana, RNA, 2003, 9, 1034-1048, Limbach et al. Nucleic Acids Research, 1994, 22, 2183-2196 and Revankar and Rao, Comprehensive Natural Products Chemistry, vol.7, 313. In some embodiments, a modified nucleobase is substituted uracil, thymine, adenine, cytosine, or guanine. In some embodiments, a modified nucleobase is a functional replacement, e.g., in terms of hydrogen bonding and / or base pairing, of uracil, thymine, adenine, cytosine, or guanine. In some embodiments, a nucleobase is optionally substituted uracil, thymine, adenine, cytosine, 5-methylcytosine, or guanine. In some embodiments, a nucleobase is uracil, thymine, adenine, cytosine, 5-methylcytosine, or guanine.

[0142] In some embodiments, a provided oligonucleotide comprises one or more 5-methylcytosine. In some embodiments, the present disclosure provides an oligonucleotide whose base sequence is disclosed herein, e.g., in Table 1, wherein each T may be independently replaced with U and vice versa, and each cytosine is optionally and independently replaced with 5-methylcytosine or vice versa. As appreciated by those skilled in the art, in some embodiments, 5mC may be treated as C with respect to base sequence of an oligonucleotide - such oligonucleotide comprises a nucleobase modification at the C position (e.g., see various oligonucleotides in Table 1). In description of oligonucleotides, typically unless otherwise noted, nucleobases, sugars and internucleotidic linkages are non-modified.

[0143] In some embodiments, a modified base is optionally substituted adenine, cytosine, guanine, thymine, or uracil, or a tautomer thereof. In some embodiments, a modified nucleobase is a modified adenine, cytosine, guanine, thymine or uracil, modified by one or more modifications by which: a nucleobase is modified by one or more optionally substituted groups independently selected from acyl, halogen, amino, azide, alkyl, alkenyl, alkynyl, aryl, heteroalkyl, heteroalkenyl, heteroalkynyl, heterocyclyl, heteroaryl, carboxyl, hydroxyl, biotin, avidin, streptavidin, substituted silyl, and combinations thereof;one or more atoms of a nucleobase are independently replaced with a different atom selected from carbon, nitrogen and sulfur; one or more double bonds in a nucleobase are independently hydrogenated; or one or more aryl or heteroaryl rings are independently inserted into a nucleobase.

[0144] In some embodiments, a base is optionally substituted A, T, C, G or U. In some embodiments, a modified base is substituted A, T, C, G or U, wherein the modified base is different than the natural A, T, C, G and U. In some embodiments, a modified base is a substituted tautomer of A, T, C, G or U.

[0145] In some embodiments, a modified nucleobase is a modified nucleobase known in the art, e.g., WO2017 / 210647. In some embodiments, modified nucleobases are expanded-size nucleobases in which one or more aryl and / or heteroaryl rings, such as phenyl rings, have been added. Certain examples of modified nucleobases, including nucleobase replacements, are described in the Glen Research catalog (Glen Research, Sterling, Virginia); Krueger AT et al., Acc. Chem. Res., 2007, 40, 141-150; Kool, ET, Acc. Chem. Res., 2002, 35, 936-943; Benner S.A., et al., Nat. Rev. Genet., 2005, 6, 553-543; Romesberg, F.E., et al., Curr. Opin. Chem. Biol., 2003, 7, 723-733; or Hirao, I., Curr. Opin. Chem. Biol., 2006, 10, 622-627. In some embodiments, an expanded-size nucleobase is an expanded-size nucleobase described in, e.g., WO2017 / 210647. In some embodiments, modified nucleobases are moieties such as corrin- or porphyrin- derived rings. Certain porphyrin-derived base replacements have been described in, e.g., Morales-Rojas, H and Kool, ET, Org. Lett., 2002, 4, 4377-4380. In some embodiments, a porphyrin-derived ring is a porphyrin- derived ring described in, e.g., WO2017 / 219647. In some embodiments, a modified nucleobase is a modified nucleobase described in, e.g., WO2017 / 219647. In some embodiments, a modified nucleobase is fluorescent. Examples of such fluorescent modified nucleobases include phenanthrene, pyrene, stillbene, isoxanthine, isozanthopterin, terphenyl, terthiophene, benzoterthiophene, coumarin, lumazine, tethered stillbene, benzo- uracil, naphtho-uracil, etc., and those described in e.g., WO2017 / 210647. In some embodiments, a nucleobase or modified nucleobase is selected from: C5-propyne T, C5-propyne C, C5-Thiazole, phenoxazine, 2-thio- thymine, 5-triazolylphenyl-thymine, diaminopurine, and N2-aminopropylguanine.

[0146] In some embodiments, a modified nucleobase is selected from 5-substituted pyrimidines, 6- azapyrimidines, alkyl or alkynyl substituted pyrimidines, alkyl substituted purines, and N-2, N-6 and O-6 substituted purines. In certain embodiments, modified nucleobases are selected from 2-aminopropyladenine, 5-hydroxymethyl cytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-N-methylguanine, 6-N-methyladenine, 2-propyladenine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-propynyl (−C C-CH3)uracil, 5-propynylcytosine, 6-azouracil, 6-azocytosine, 6-azothymine, 5-ribosyluracil (pseudouracil), 4- thiouracil, 8-halo, 8-amino, 8-thiol, 8-thioalkyl, 8-hydroxyl, 8-aza and other 8-substituted purines, 5-halo, particularly 5-bromo, 5-trifluoromethyl, 5-halouracil, and 5-halocytosine, 7-methylguanine, 7-methyladenine, 2-F-adenine, 2-aminoadenine, 7-deazaguanine, 7-deazaadenine, 3-deazaguanine, 3-deazaadenine, 6-N- benzoyladenine, 2-N-isobutyrylguanine, 4-N-benzoylcytosine, 4-N-benzoyluracil, 5-methyl 4-N-benzoylcytosine, 5-methyl 4-N-benzoyluracil, universal bases, hydrophobic bases, promiscuous bases, size- expanded bases, and fluorinated bases. In some embodiments, modified nucleobases are tricyclic pyrimidines, such as l,3-diazaphenoxazine-2-one, l,3-diazaphenothiazine-2-one or 9-(2-aminoethoxy)-l,3- diazaphenoxazine-2- one (G-clamp). In some embodiments, modified nucleobases are those in which the purine or pyrimidine base is replaced with other heterocycles, for example, 7-deaza-adenine, 7- deazaguanosine, 2-aminopyridine or 2- pyridone. In some embodiments, modified nucleobases are those disclosed in US 3687808, The Concise Encyclopedia Of Polymer Science And Engineering, Kroschwitz, J.I., Ed., John Wiley & Sons, 1990, 858-859; Englisch et al., Angewandte Chemie, International Edition, 1991, 30, 613; Sanghvi, Y.S., Chapter 15, Antisense Research and Applications, Crooke, S.T. and Lebleu, B., Eds., CRC Press, 1993, 273-288; or in Chapters 6 and 15, Antisense Drug Technology, Crooke S.T., Ed., CRC Press, 2008, 163-166 and 442-443.

[0147] In some embodiments, modified nucleobases and methods thereof are those described in US 20030158403, US 3687808, US 4845205, US 5130302, US 5134066, US 5175273, US 5367066, US 5432272, US 5434257, US 5457187, US 5459255, US 5484908, US 5502177, US 5525711, US 5552540, US 5587469, US 5594121, US 5596091, US 5614617, US 5645985, US 5681941, US 5750692, US 5763588, US 5830653, or US 6005096.

[0148] In some embodiments, a modified nucleobase is substituted. In some embodiments, a modified nucleobase is substituted such that it contains, e.g., heteroatoms, alkyl groups, or linking moieties connected to fluorescent moieties, biotin or avidin moieties, or other protein or peptides. In some embodiments, a modified nucleobase is a “universal base” that is not a nucleobase in the most classical sense, but that functions similarly to a nucleobase. One example of a universal base is 3-nitropyrrole.

[0149] In some embodiments, nucleosides that can be utilized in provided technologies comprise modified nucleobases and / or modified sugars, e.g., 4-acetylcytidine; 5-(carboxyhydroxylmethyl)uridine; 2’- O-methylcytidine; 5-carboxymethylaminomethyl-2-thiouridine; 5-carboxymethylaminomethyluridine; dihydrouridine; 2’-O-methylpseudouridine; beta,D-galactosylqueosine; 2’-O-methylguanosine; N6- isopentenyladenosine; 1-methyladenosine; 1-methylpseudouridine; 1-methylguanosine; l-methylinosine; 2,2- dimethylguanosine; 2-methyladenosine; 2-methylguanosine; N7-methylguanosine; 3-methyl-cytidine; 5- methylcytidine; 5-hydroxymethylcytidine; 5-formylcytosine; 5-carboxylcytosine; N6-methyladenosine; 7- methylguanosine; 5-methylaminoethyluridine; 5-methoxyaminomethyl-2-thiouridine; beta,D- mannosylqueosine; 5-methoxycarbonylmethyluridine; 5-methoxyuridine; 2-methylthio-N6- isopentenyladenosine; N-((9-beta,D-ribofuranosyl-2-methylthiopurine-6-yl)carbamoyl)threonine; N-((9- beta,D-ribofuranosylpurine-6-yl)-N-methylcarbamoyl)threonine; uridine-5-oxyacetic acid methylester; uridine-5-oxyacetic acid (v); pseudouridine; queosine; 2-thiocytidine; 5-methyl-2-thiouridine; 2-thiouridine; 4-thiouridine; 5-methyluridine; 2’-O-methyl-5-methyluridine; and 2’-O-methyluridine.

[0150] In some embodiments, a nucleobase, e.g., a modified nucleobase comprises one or more biomolecule binding moieties such as e.g., antibodies, antibody fragments, biotin, avidin, streptavidin, receptorligands, or chelating moieties. In other embodiments, a nucleobase is 5-bromouracil, 5-iodouracil, or 2,6- diaminopurine. In some embodiments, a nucleobase comprises substitution with a fluorescent or biomolecule binding moiety. In some embodiments, a substituent is a fluorescent moiety. In some embodiments, a substituent is biotin or avidin.

[0151] Certain examples of nucleobases and related methods are described in US 3687808, 4845205, US 513030, US 5134066, US 5175273, US 5367066, US 5432272, US 5457187, US 5457191, US 5459255, US 5484908, US 5502177, US 5525711, US 5552540, US 5587469, US 5594121, US 5596091, US 5614617, US 5681941, US 5750692, US 6015886, US 6147200, US 6166197, US 6222025, US 6235887, US 6380368, US 6528640, US 6639062, US 6617438, US 7045610, US 7427672, US or US 7495088.

[0152] In some embodiments, an oligonucleotide comprises a nucleobase, sugar, nucleoside, and / or internucleotidic linkage which is described in any of: Gryaznov, S; Chen, J.-K. J. Am. Chem. Soc.1994, 116, 3143; Hendrix et al.1997 Chem. Eur. J.3: 110; Hyrup et al.1996 Bioorg. Med. Chem.4: 5; Jepsen et al.2004 Oligo.14: 130-146; Jones et al. J. Org. Chem.1993, 58, 2983; Koizumi et al.2003 Nuc. Acids Res.12: 3267- 3273; Koshkin et al. 1998 Tetrahedron 54: 3607-3630; Kumar et al. 1998 Bioo. Med. Chem. Let. 8: 2219- 2222; Lauritsen et al.2002 Chem. Comm.5: 530-531; Lauritsen et al.2003 Bioo. Med. Chem. Lett.13: 253- 256; Mesmaeker et al. Angew. Chem., Int. Ed. Engl.1994, 33, 226; Morita et al.2001 Nucl. Acids Res. Supp. 1: 241-242; Morita et al. 2002 Bioo. Med. Chem. Lett.12: 73-76; Morita et al.2003 Bioo. Med. Chem. Lett. 2211-2226; Nielsen et al.1997 Chem. Soc. Rev.73; Nielsen et al.1997 J. Chem. Soc. Perkins Transl.1: 3423- 3433; Obika et al.1997 Tetrahedron Lett.38 (50): 8735–8; Obika et al.1998 Tetrahedron Lett.39: 5401-5404; Pallan et al.2012 Chem. Comm.48: 8195-8197; Petersen et al.2003 TRENDS Biotech.21: 74-81; Rajwanshi et al.1999 Chem. Commun. 1395-1396; Schultz et al.1996 Nucleic Acids Res.24: 2966; Seth et al.2009 J. Med. Chem. 52: 10-13; Seth et al. 2010 J. Med. Chem. 53: 8309-8318; Seth et al. 2010 J. Org. Chem. 75: 1569-1581; Seth et al. 2012 Bioo. Med. Chem. Lett. 22: 296-299; Seth et al.2012 Mol. Ther-Nuc. Acids.1, e47; Seth, Punit P; Siwkowski, Andrew; Allerson, Charles R; Vasquez, Guillermo; Lee, Sam; Prakash, Thazha P; Kinberger, Garth; Migawa, Michael T; Gaus, Hans; Bhat, Balkrishen; et al. From Nucleic Acids Symposium Series (2008), 52(1), 553-554; Singh et al. 1998 Chem. Comm. 1247-1248; Singh et al. 1998 J. Org. Chem. 63: 10035-39; Singh et al.1998 J. Org. Chem.63: 6078-6079; Sorensen 2003 Chem. Comm.2130-2131; Ts'o et al. Ann. N. Y. Acad. Sci.1988, 507, 220; Van Aerschot et al.1995 Angew. Chem. Int. Ed. Engl.34: 1338; Vasseur et al. J. Am. Chem. Soc.1992, 114, 4006; WO 2007090071; or WO 2016 / 079181.

[0153] In some embodiments, an oligonucleotide comprises a modified nucleobase, nucleoside or nucleotide which is described in any of: Feldman et al.2017 J. Am. Chem. Soc.139: 11427-11433, Feldman et al.2017 Proc. Natl. Acad. Sci. USA 114: E6478-E6479, Hwang et al.2009 Nucl. Acids Res.37: 4757-4763, Hwang et al. 2008 J. Am. Chem. Soc.130: 14872-14882, Lavergne et al.2012 Chem. Eur. J.18: 1231-1239, Lavergne et al. 2013 J. Am. Chem. Soc. 135: 5408-5419, Ledbetter et al.2018 J. Am. Chem. Soc. 140: 758- 765, Malyshev et al.2009 J. Am. Chem. Soc.131: 14620-14621, Seo et al.2009 Chem. Bio. Chem.10: 2394- 2400, e.g., d3FB, d2Py analogs, d2Py, d3MPy, d4MPy, d5MPy, d34DMPy, d35DMPy, d45DMPy, d5FM,d5PrM, d5SICS, dFEMO, dMMO2, dNaM, dNM01, dTPT3, nucleotides with 2’-azido, 2’-chloro, 2’-amino or arabinose sugars, isocarbostiryl-, napthyl- and azaindole-nucleotides, and modifications and derivatives and functionalized versions thereof, e.g., those in which the sugar comprises a 2’-modification and / or other modification, and dMMO2 derivatives with meta-chlorine, -bromine, -iodine, -methyl, or -propinyl substituents.

[0154] In some embodiments, a nucleobase comprises at least one optionally substituted ring which comprises a heteroatom ring atom. In some embodiments, a nucleobase comprises at least one optionally substituted ring which comprises a nitrogen ring atom. In some embodiments, such a ring is aromatic. In some embodiments, a nucleobase is bonded to a sugar through a heteroatom. In some embodiments, a nucleobase is bonded to a sugar through a nitrogen atom. In some embodiments, a nucleobase is bonded to a sugar through a ring nitrogen atom.

[0155] In some embodiments, an oligonucleotide comprises a nucleobase or modified nucleobase as described in: WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the bases and modified nucleobases of each of which are independently incorporated herein by reference.

[0156] In some embodiments, a nucleobase is an optionally substituted purine base residue. In some embodiments, a nucleobase is a protected purine base residue. In some embodiments, a nucleobase is an optionally substituted adenine residue. In some embodiments, a nucleobase is a protected adenine residue. In some embodiments, a nucleobase is an optionally substituted guanine residue. In some embodiments, a nucleobase is a protected guanine residue. In some embodiments, a nucleobase is an optionally substituted cytosine residue. In some embodiments, a nucleobase is a protected cytosine residue. In some embodiments, a nucleobase is an optionally substituted thymine residue. In some embodiments, a nucleobase is a protected thymine residue. In some embodiments, a nucleobase is an optionally substituted uracil residue. In some embodiments, a nucleobase is a protected uracil residue. In some embodiments, a nucleobase is an optionally substituted 5-methylcytosine residue. In some embodiments, a nucleobase is a protected 5-methylcytosine residue.

[0157] In some embodiments, a provided oligonucleotide comprises a modified nucleobase described in, e.g., US 5552540, US 6222025, US 6528640, US 4845205, US 5681941, US 5750692, US 6015886, US 5614617, US 6147200, US 5457187, US 6639062, US 7427672, US 5459255, US 5484908, US 7045610, US 3687808, US 5502177, US 55257116235887, US 5175273, US 6617438, US 5594121, US 6380368, US 5367066, US 5587469, US 6166197, US 5432272, US 7495088, US 5134066, or US 5596091. In some embodiments, a nucleobase is described in WO 2020 / 154344, WO 2020 / 154343, WO 2020 / 154342, WO 2020 / 165077, WO 2020 / 201406, WO 2020 / 216637, or WO 2020 / 252376, and can be utilized in accordance with the present disclosure.

[0158] In some embodiments, a nucleobase is a protected base residue as used in oligonucleotidepreparation. In some embodiments, a nucleobase is a base residue illustrated in US 2011 / 0294124, US 2015 / 0211006, US 2015 / 0197540, WO 2015 / 107425, WO 2017 / 192679, WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the base residues of each of which are independently incorporated herein by reference. Sugars

[0159] Various sugars, including modified sugars, can be utilized in accordance with the present disclosure. In some embodiments, the present disclosure provides sugar modifications and patterns thereof optionally in combination with other structural elements (e.g., internucleotidic linkage modifications and patterns thereof, pattern of backbone chiral centers thereof, etc.) that when incorporated into oligonucleotides can provide improved properties and / or activities.

[0160] The most common naturally occurring nucleosides comprise ribose sugars (e.g., in RNA) or deoxyribose sugars (e.g., in DNA) linked to the nucleobases adenosine (A), cytosine (C), guanine (G), thymine (T) or uracil (U). In some embodiments, a sugar, e.g., various sugars in many oligonucleotides in Table 1 (unless otherwise notes), is a natural DNA sugar (in DNA nucleic acids or oligonucleotides, having the structure of , wherein a nucleobase is attached to the 1’ position, and the 3’ and 5’ positions areconnected to internucleotidic linkages (as appreciated by those skilled in the art, if at the 5’-end of oligonucleotide, the 5’ position may be connected to a 5’-end group (e.g., −OH), and if at the 3’-end of an oligonucleotide, the 3’ position may be connected to a 3’-end group (e.g., −OH). In some embodiments, a sugar is a natural RNA sugar (in RNA nucleic acids or oligonucleotides, having the structure of, wherein a nucleobase is attached to the 1’ position, and the 3’ and 5’ positions are connected to internucleotidic linkages (as appreciated by those skilled in the art, if at the 5’-end of an oligonucleotide, the 5’ position may be connected to a 5’-end group (e.g., −OH), and if at the 3’-end of an oligonucleotide, the 3’ position may be connected to a 3’-end group (e.g., −OH). In some embodiments, a sugar is a modified sugar in that it is not a natural DNA sugar or a natural RNA sugar. Among other things, modified sugars may provide improved stability. In some embodiments, modified sugars can be utilized to alter and / or optimize one or more hybridization characteristics. In some embodiments, modified sugars can be utilized to alter and / or optimize target nucleic acid recognition. In some embodiments, modified sugars can be utilized to optimize Tm. In some embodiments, modified sugars can be utilized to improve oligonucleotide activities.

[0161] Among other things, the present disclosure demonstrates that various non-natural RNA sugars,such as natural DNA sugar, various modified sugars (e.g., 2’-F modified sugars, 2’-OMe modified sugars), etc., may be utilized in accordance with the present disclosure.

[0162] Sugars can be bonded to internucleotidic linkages at various positions. As non-limiting examples, internucleotidic linkages can be bonded to the 2’, 3’, 4’ or 5’ positions of sugars. In some embodiments, as most commonly in natural nucleic acids, an internucleotidic linkage connects with one sugar at the 5’ position and another sugar at the 3’ position unless otherwise indicated.

[0163] In some embodiments, a sugar is an optionally substituted natural DNA or RNA sugar. In some embodiments, a sugar is optionally substitutedn some embodiments, the 2’ position is optionally substituted. In some embodiments, a sugar isn some embodiments, a sugar has the structure owherein each of R1s, R2s, R3s, R4s, and R5sis independently −H, a suitable substituent or suitable sugar modification (e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the substituents, sugar modifications, descriptions of R1s, R2s, R3s, R4s, and R5s, and modified sugars of each of which are independently incorporated herein by reference). In some embodiments, each of R1s, R2s, R3s, R4s, and R5sis independently Rs, wherein each Rsis independently −F, −Cl, −Br, −I, −CN, −N3, −NO, −NO2, −Ls−R’, −Ls−OR’, −Ls−SR’, −Ls−N(R’)2, −O−Ls−OR’, −O−Ls−SR’, or −O−Ls−N(R’)2, wherein each R’ is independently as described herein, and each Lsis independently a covalent bond or optionally substituted bivalent C1-6aliphatic or heteroaliphatic having 1-4 heteroatoms; or two Rsare taken together to form a bridge −Ls−. In some embodiments, R’ is optionally substituted C1-10 aliphatic. In some embodiments, a sugar has the structure of In some embodiments, a sugar has the structure of n someembodiments, a sugar has the structure oome embodiments, a sugar has the structure of. In some embodiments, a sugar has the structure of. In some embodiments, a sugar has the structure ofIn some embodiments, a sugar has the structure ofIn some embodiments, a sugar has the structure ofome embodiments, a sugar has the structure oIn some embodiments, R5sis optionally substituted C1-6 aliphatic. In some embodiments, R5sis optionally substituted C1-6 alkyl. In some embodiments, R5sis optionally substituted methyl. In some embodiments, R5sis methyl. In some embodiments, a sugar has the structure of In some embodiments, a sugar has the structure ofIn some embodiments, asugar has the structure ofVarious such sugars are utilized in Table 1. In some embodiments, a sugar has the structure oome embodiments, a 2’-modified sugar has the structure ofwherein R2sis a 2’-modification. In some embodiments, a sugar has the structure of, wherein R2sis −H, halogen, or −OR, wherein R is optionally substituted C1-6 aliphatic. In some embodiments, R2sis −H. In some embodiments, R2sis −F. In some embodiments, R2sis −OMe. In some embodiments, a modified nucleoside is mA, mT, mC, m5mC, mG, mU, etc., in which R2sis −OMe. In some embodiments, R2sis −OCH2CH2OMe. In some embodiments, a modified nucleoside is Aeo, Teo, Ceo, m5Ceo, Geo, Ueo, etc., in which R2sis −OCH2CH2OMe. In some embodiments, R2sis −OCH2CH2OH. In some embodiments, an oligonucleotide comprises a 2’-F modified sugar having the structure off5mC, fG, fU, [fl2r](A), [fl2r](T), [fl2r](C), [fl2r](5mC), [fl2r](G), [fl2r](U),etc.). In some embodiments, an oligonucleotide comprises a 2’-OMe modified sugar having the structure ofg., as in mA, mT, mC, m5mC, mG, mU, m(A), m(T), m(C), m(5mC), m(G), m(U), etc.). In some embodiments, an oligonucleotide comprises a 2’-MOE modified sugar having the structure ofin Aeo, Teo, Ceo, m5Ceo, Geo, Ueo, [moe](A), [moe](T), [moe](C), [moe](5mC), [moe](G), [moe](U), etc.).

[0164] In some embodiments, a sugar has the structure of, wherein R2sand R4sare taken together to form −Ls−, wherein Lsis a covalent bond or optionally substituted bivalent C1-6aliphatic or heteroaliphatic having 1-4 heteroatoms. In some embodiments, each heteroatom is independently selected from nitrogen, oxygen or sulfur). In some embodiments, Lsis optionally substituted C2−O−CH2−C4. In some embodiments, Lsis C2−O−CH2−C4. In some embodiments, Lsis C2−O−(R)-CH(CH2CH3)−C4. In some embodiments, Lsis C2−O−(S)-CH(CH2CH3)−C4.

[0165] In some embodiments, a sugar has the structure ofherein each variable is independently as described herein. In some embodiments, a sugar has the structure ofwhereineach variable is independently as described herein. In some embodiments, R5sis −H. In some embodiments, a sugar has the structure ofwherein each variable is independently as described herein. In some embodiments, R3sis −OH. In some embodiments, R3sis −H. In some embodiments, a sugar isIn some embodiments, a sugar is

[0166] In some embodiments, a sugar is optionally substituted wherein Xsis −S−, −Se−,or optionally substituted −CH2−. In some embodiments, the 2’ position is optionally substituted. In some embodiments, a sugar isIn some embodiments, a sugar has the structure of, wherein each of R1s, R2s, R3s, R4s, and R5sis independently −H, a suitable substituent or suitable sugar modification (e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the substituents, descriptions of R1s, R2s, R3s, R4s, and R5s, and modified sugars of each of which are independently incorporated herein by reference). In some embodiments, each of R1s, R2s, R3s, R4s, and R5sis independently Rs, wherein each Rsis independently −F, −Cl, −Br, −I, −CN, −N3, −NO, −NO2, −Ls−R’, −Ls−OR’, −Ls−SR’, −Ls−N(R’)2, −O−Ls−OR’, −O−Ls−SR’, or −O−Ls−N(R’)2, wherein each R’ is independently as described herein, and each Lsis independently a covalent bond or optionally substituted bivalent C1-6 aliphatic or heteroaliphatic having 1-4 heteroatoms; or two Rsare taken together to form a bridge −Ls−. In some embodiments, R’ is optionallysubstituted C1-10 aliphatic. In some embodiments, a sugar has the structure ofn some embodiments, a sugar has the structure oome embodiments, a sugar has the structure of In some embodiments, a sugar has the structure of In some embodiments, asugar has the structure ofIn some embodiments, a sugar has the structure ofIn some embodiments, a sugar has the structure ofome embodiments, a sugar has the structure of. In some embodiments, a sugar has the structure of. In some embodiments, R5sis optionally substituted C1-6 aliphatic. In some embodiments, R5sis optionally substituted C1-6 alkyl. In some embodiments, R5sis optionally substituted methyl. In some embodiments, R5sis methyl. In some embodiments, a sugar has the structure ofome embodiments, a sugar has the structure ofIn some embodiments, a sugar has the structure Various suchsugars are utilized in Table 1. In some embodiments, a sugar has the structure ofIn some embodiments, a 2’-modified sugar has the structure of, wherein R2sis a 2’-modification. In some embodiments, a sugar has the structure ofwherein R2sis −H, halogen, or −OR, wherein R is optionally substituted C1-6aliphatic. In some embodiments, R2sis −H. In some embodiments, R2sis −F. In some embodiments, R2sis −OMe. In some embodiments, R2sis −OCH2CH2OMe. In some embodiments, R2sis −OCH2CH2OH. In some embodiments, a modified sugar has the structure ofn some embodiments, a modified sugar has the structure ofome embodiments, a modified sugar having the structure ombodiments, a modified sugar having the structure oome embodiments, Xsis −S−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−. In some embodiments, a modified sugar having the structure of. In some embodiments, a modified sugar having the structure of

[0167] In some embodiments, a sugar has the structure ofor wherein each R2sis independently −H, −F, −OH or −ORak, wherein Rakis optionally substituted C1-6 aliphatic, and each of the other variables is independently as described herein. In some embodiments, each of R1s, R3s, R4s, and R5sis independently −H. In some embodiments, each of R1s, R3sand R4s, and one of R5s, are independently −H, and the other R5sis independently C1-6 aliphatic. In some embodiments, an occurrence of R5sis C1-6 aliphatic, e.g., methyl. In some embodiments, R2sis −H. In some embodiments, R2sis −F. In some embodiments, R2sis --ORak. In some embodiments, R2sis −OMe. In some embodiments, R2sis −OCH2CH2CH3. In some embodiments, at least one occurrence of R2sis −H. In some embodiments, at least one occurrence of R2sis not −H. In some embodiments, Xsis −O−. In some embodiments, Xsis −S−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−.

[0168] In some embodiments, a sugar has the structure ofwherein R2sand R4sare taken together to form −Ls−, wherein Lsis a covalent bond or optionally substituted bivalent C1-6 aliphatic or heteroaliphatic having 1-4 heteroatoms. In some embodiments, each heteroatom is independently selected from nitrogen, oxygen or sulfur). In some embodiments, Lsis optionally substituted C2−O−CH2−C4. In some embodiments, Lsis C2−O−CH2−C4. In some embodiments, Lsis C2−O−(R)-CH(CH2CH3)−C4. In some embodiments, Lsis C2−O−(S)-CH(CH2CH3)−C4. In some embodiments, Xsis −S−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−. In some embodiments, Xsis −Se−.

[0169] In some embodiments, a sugar has the structure ofherein each variable isindependently as described herein. In some embodiments, a sugar has the structure of , wherein each variable is independently as described herein. In some embodiments, R5sis −H. In some embodiments,a sugar has the structure owherein each variable is independently as described herein. In some embodiments, R3sis −OH. In some embodiments, R3sis −H. In some embodiments, Xsis −S−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−.

[0170] In some embodiments, a nucleoside comprising a modified sugar has the structure ofor a salt form thereof, wherein BAsis −H or an optionally substituted or protected nucleobase (e.g., BA), and R2sis as described herein. In some embodiments, R2sis −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, BAsis −H. In some embodiments, BAsis an optionally substituted or protected nucleobase. In some embodiments, BAsis BA. In some embodiments, R2sis −F. In some embodiments, a nucleoside comprising a modified sugar has the structure ofa salt form thereof, wherein each variable is independently as described herein. In some embodiments, R2sis −H, −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, R2sis −H. In some embodiments, R2sis −F. In some embodiments, a nucleoside comprising a modified sugar has the structure of , wherein each variable is as described herein. In some embodiments, a nucleoside comprising a modified sugar has the structure ofr a salt form thereof, wherein each variable is independently as described herein. In some embodiments, R2sis −H, −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, R2sis −H. In some embodiments, R2sis −F. In some embodiments, a nucleoside comprising a modified sugar has the structure oflt form thereof, wherein R2s’is Rs, and each of Rs, R2sand BAsis independently as described herein. In some embodiments, each of R2sand R2s’is independently −H, −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, R2sis −H. In some embodiments, R2sis −OH. In some embodiments, R2sis halogen. In some embodiments, R2sis −F. In some embodiments, R2sis optionally substituted C1-C6 alkoxy. In some embodiments, R2s’is −H. In some embodiments, R2s’is −OH. In some embodiments, R2s’is halogen. In some embodiments, R2s’is −F. In someembodiments, R2s’is optionally substituted C1-C6 alkoxy. In some embodiments, BAsis −H. In some embodiments, BAsis an optionally substituted or protected nucleobase. In some embodiments, BAsis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. Certain such nucleosides including sugars and nucleobases and uses thereof are described in WO 2020 / 154342. In some embodiments, an oligonucleotide comprises arabinoside, 2’-deoxy-2’-fluoro- arabinoside, 2’-OR arabinoside, adeoxycytidine, DNA-abasic, RNA-abasic, or 2’-OR abasic, wherein R is not hydrogen (e.g., optionally substituted C1-6 aliphatic). In some embodiments, 2’-OR is 2’-OMe. In some embodiments, 2’-OR is 2’-MOE. In some embodiments, an oligonucleotide comprises 2’-O-methyl- arabinocytidine (amC). In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, monomers comprise such nucleosides. In some embodiments, phosphoramidites comprise such nucleosides (in some embodiments, one connecting site (e.g., a −CH2− connecting site) is bonded to an optionally substituted −OH, e.g., (−ODMTr), and one connecting site (e.g., a ring connecting site) is bonded to O which is also bonded to P of a phosphoramidite). In some embodiments, a sugar has the structure of, wherein each variable is as described herein and C1’ is bonded to a nucleobase. In some embodiments, a sugar is an arabinose. In some embodiments, a sugar has the structure ofwherein C1’ is bonded to a nucleobase.

[0171] In some embodiments, a sugar is optionally substituted, wherein a nucleobase is bonded at position 1’. In some embodiments, a sugar iswherein a nucleobase is bonded at position 1’.

[0172] In some embodiments, a sugar is optionally substituted, wherein position a is bonded to a nucleobase, Xsis −O−, −S−, −Se− or optionally substituted −C n some embodiments, a sugaris n some embodiments, a sugar is optionally substituted whereinposition a is bonded to a nucleobase, Xsis −O−, −S−, −Se− or optionally substituted −CH2−. In some embodiments, a sugar isIn some embodiments, Xsis −O−. In some embodiments, Xsis −S−. In some embodiments, Xsis −Se−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−. In some embodiments, n is 0. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3.

[0173] In some embodiments, a modified sugar comprises an optionally substituted 6-membered ring having 0-1 oxygen atom. In some embodiments, a modified sugar comprises an optionally substituted 6- membered ring having an oxygen atom. For example, in some embodiments, a modified sugar has the structure of optionally substituted, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of wherein position a is bonded to anucleobase. in some embodiments, a modified sugar has the structure of optionally substituted , wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of optionally substituted, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure ofwherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of optionally substituted, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar hasthe structure ofwherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of optionally substitutedwherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure ofherein position a is bonded to a nucleobase.

[0174] In some embodiments, a nucleoside comprising a modified sugar has the structure ofsalt form thereof, wherein each of R6sand R7sis independently Rs, BAsis −H or an optionally substituted or protected nucleobase (e.g., BA), and Rsis independently as described herein. In some embodiments, R6sis −H, −OH or halogen, and R7sis −H, −OH, halogen or optionally substituted C1-C6alkoxy. In some embodiments, BAsis −H. In some embodiments, BAsis an optionally substituted or protected nucleobase. In some embodiments, BAsis BA. In some embodiments, a nucleoside comprising a modified sugar has the structure oalt form thereof, wherein each of R8sand R9sis independently Rs, and each of Rsand BAsis independently as described herein. In some embodiments, R8sis −H or halogen, and R9sis −H, −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, a nucleoside comprising a modified sugar has the structure oflt form thereof, wherein each of R10sand R11sis independently Rs, and each of Rsand BAsis independently as described herein. In some embodiments, R10sis −H or halogen, and R11sis −H, −OH, halogen, or optionally substituted C1-C6 alkoxy. In some embodiments, a nucleoside comprising a modified sugar has the structure of or a salt form thereof, wherein BAsis as described herein. In some embodiments, anucleoside comprising a modified sugar has the structure of r a salt form thereof, whereinBAsis as described herein. Those skilled in the art appreciate that in some embodiments, the nitrogen may be directly bonded to linkage phosphorus. In some embodiments, a halogen is −F. In some embodiments, BAsis −H. In some embodiments, BAsis an optionally substituted or protected nucleobase. In some embodiments, BAsis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. In some embodiments, an oligonucleotide comprises alpha-homo-DNA, beta- homo-DNA moieties. In some embodiments, an oligonucleotide comprises an alpha- or beta-homo-DNA sugar. In some embodiments, an oligonucleotide comprises an alpha-homo-DNA sugar. In some embodiments, an oligonucleotide comprises a beta-homo-DNA sugar. Certain such nucleosides including sugars and nucleobases and uses thereof are described in WO 2020 / 154343. In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, monomers comprise such nucleosides. In some embodiments, phosphoramidites comprise such nucleosides (in some embodiments, one connecting site (e.g., a −CH2− connecting site) is bonded to an optionally substituted −OH, e.g., −ODMTr, and one connecting site (e.g., a ring connecting site) is bonded to P of a phosphoramidite (e.g., when the connecting ring atom is N) or to O which is also bonded to P of a phosphoramidite(e.g., when the connecting ring atom is C)).

[0175] In some embodiments, a modified sugar has the structure of wherein position ais bonded to a nucleobase. In some embodiments, a modified sugar has the structure ofwherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of, wherein position a is bonded to a nucleobase, position b is bonded to an internucleoside linkage and R’’ is −H or optionally substituted C1-6 aliphatic. In some embodiments, a modified sugar has the structure owherein position a is bonded to a nucleobase, position b is bonded to an internucleoside linkage and R’’ is −H or C1-6 aliphatic. In some embodiments, a modified sugar has thestructure owherein position a is bonded to a nucleobase, position b is bonded to an internucleoside linkage and R’’ is −H or C1-6aliphatic. In some embodiments, R” is methyl.

[0176] In some embodiments, a nucleoside comprising a modified sugar has the structure of or a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleoside comprising a modified sugar has the structure of a salt form thereof, wherein each variable is asdescribed herein. In some embodiments, a nucleoside comprising a modified sugar has the structure ofor a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleoside comprising a modified sugar has the structure oflt form thereof, wherein R12sis Rs, and each of Rsand BAsis independently as described herein. In some embodiments, R12sis −H, −OH, halogen, optionally substituted C1-6 alkyl, optionally substituted C1-6 heteroalkyl, or optionally substituted C1-6 alkoxy. In some embodiments, a halogen is −F. In some embodiments, a nucleoside comprising a modified sugar has the structure ofr a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleotide comprising a modified sugar has the structure oalt form thereof, wherein R13sis Rs, and each of Rsand BAsis independently as described herein. In some embodiments, R13sis −H or optionally substituted C1-C6 alkyl. Insome embodiments, a nucleoside comprising a modified sugar has the structure ofor a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleotide comprising a modified sugar has the structure oflt form thereof, wherein each variable is as described herein. In some embodiments, a linkage is an amide linkage. In some embodiments, BAsis −H. In some embodiments, BAsis an optionally substituted or protected nucleobase. In some embodiments, BAsis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. Certain such nucleosides and nucleotides including sugars and nucleobases and uses thereof are described in WO 2020 / 154344. In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, oligonucleotides comprise such nucleosides (in some embodiments, one connecting site (e.g., a −CH2− connecting site) is bonded to an optionally substituted −OH, e.g., (−ODMTr), and one connecting site (e.g., a ring connecting site) is bonded to O which is also bonded to P of a phosphoramidite.

[0177] In some embodiments, a sugar is an acyclic sugar, e.g., a UNA sugar. In some embodiments, a sugar is optionally substitutedn some embodiments, the 2’ position is optionally substituted. In some embodiments, a sugar is In some embodiments, a sugar has the structure ofIn some embodiments, R2sis −OH. In some embodiments, a sugar isindicates the carbon atom bonded to a nucleobase. In some embodiments, a sugar isherein “*”indicates the carbon atom bonded to a nucleobase. In some embodiments, the carbon atom bonded to a nitrogen atom of a nucleobase and is of R configuration (e.g., sm18). In some embodiments, an oligonucleotide comprises a sugar described herein.

[0178] In some embodiments, a sugar is optionally substitutedwherein position a is bonded to a nucleobase, Xsis −O−, −S−, −Se− or optionally substituted −CH2−. In some embodiments, a sugar is In some embodiments, Xsis −O−. In some embodiments, Xsis −S−. In someembodiments, Xsis −Se−. In some embodiments, Xsis optionally substituted −CH2−. In some embodiments, Xsis −CH2−. In some embodiments, n is 0. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3.

[0179] In some embodiments, a sugar is connected not through 5’ and 3’ positions. Those skilled in the art appreciate that for such sugars, 5’ can refer to the side / direction toward 5’-end of an oligonucleotide, and 3’ can refer to the side / direction toward to 3’-end of an oligonucleotide.

[0180] In some embodiments, each of R1s, R2s, R3s, R4s, and R5sis independently Rs, wherein Rsis independently −H, halogen, −CN, −N3, −NO, −NO2, −Ls−R’, −Ls−Si(R’)3, −Ls−OR’, −Ls−SR’, −Ls−N(R’)2, −O−Ls−R’, −O−Ls−Si(R)3, −O−Ls−OR’, −O−Ls−SR’, or −O−Ls−N(R’)2; wherein Lsis LBas described herein, and each other variable is independently as described herein. In some embodiments, each of R1sand R2sis independently Rs. In some embodiments, Rsis −H. In some embodiments, Rsis not −H. In some embodiments, Lsis a covalent bond. In some embodiments, each of R2sand R4sare independently −H, −F, −OR, −N(R)2. In some embodiments, R2sis −H, −F, −OR, −N(R)2. In some embodiments, R4sis −H. In some embodiments, R2sand R4sform 2’−O−Ls−, wherein Lsis optionally substituted C1-6alkylene. In some embodiments, Lsis optionally substituted −CH2−. In some embodiments, Lsis optionally substituted −CH2−.

[0181] In some embodiments, R is hydrogen. In some embodiments, R is not hydrogen. In some embodiments, R is an optionally substituted group selected from C1-10 aliphatic, C1-10 heteroaliphatic having 1- 10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, C6-20 aryl, a 5- 20 membered heteroaryl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, and a 3-20 membered heterocyclic ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon.

[0182] In some embodiments, R is optionally substituted C1-30 aliphatic. In some embodiments, R is optionally substituted C1-20 aliphatic. In some embodiments, R is optionally substituted C1-15 aliphatic. In some embodiments, R is optionally substituted C1-10 aliphatic. In some embodiments, R is optionally substituted C1-6 aliphatic. In some embodiments, R is optionally substituted C1-6 alkyl. In some embodiments, R is optionally substituted hexyl, pentyl, butyl, propyl, ethyl or methyl. In some embodiments, R is optionallysubstituted hexyl. In some embodiments, R is optionally substituted pentyl. In some embodiments, R is optionally substituted butyl. In some embodiments, R is optionally substituted propyl. In some embodiments, R is optionally substituted ethyl. In some embodiments, R is optionally substituted methyl. In some embodiments, R is hexyl. In some embodiments, R is pentyl. In some embodiments, R is butyl. In some embodiments, R is propyl. In some embodiments, R is ethyl. In some embodiments, R is methyl. In some embodiments, R is isopropyl. In some embodiments, R is n-propyl. In some embodiments, R is tert-butyl. In some embodiments, R is sec-butyl. In some embodiments, R is n-butyl. In some embodiments, R is −(CH2)2OCH3.

[0183] In some embodiments, R is optionally substituted phenyl. In some embodiments, R is phenyl.

[0184] In some embodiments, R2sis a 2’-modification as described in the present disclosure, and R4sis −H. In some embodiments, R2sis −OR, wherein R is not hydrogen. In some embodiments, R2sis −F. In some embodiments, R2sis −OMe. In some embodiments, R2sis −OCH2CH2CH3, e.g., in various Xeo utilized in Table 1 (X being m5C, T, G, A, etc.). In some embodiments, R2sis selected from −H, −F, and −OR, wherein R is optionally substituted C1-6alkyl. In some embodiments, R2sis selected from −H, −F, and −OMe.

[0185] In some embodiments, a sugar is a bicyclic sugar, e.g., sugars wherein R2sand R4sare taken to form an optionally substituted ring as described in the present disclosure. In some embodiments, a sugar is selected from LNA sugars, BNA sugars, cEt sugars, etc. In some embodiments, a bridge is between the 2’ and 4’-carbon atoms (corresponding to R2sand R4staken together with their intervening atoms to form an optionally substituted ring as described herein). In some embodiments, a bridge is 2’−La−Lb−4’, wherein Lais −O−, −S− or N(R), and Lbis an optionally substituted C1-4bivalent aliphatic chain, e.g., methylene.

[0186] In some embodiments, a sugar is a 2’-OMe, 2’-MOE, 2’-F, a LNA (locked nucleic acid) sugar, an ENA (ethylene bridged nucleic acid) sugar, a BNA(NMe) (Methylamino bridged nucleic acid) sugar, 2’-F ANA (2’-F arabinose), alpha-DNA (alpha-D-ribose), 2’ / 5’ ODN (e.g., 2’ / 5’ linked oligonucleotide), Inv (inverted sugar, e.g., inverted desoxyribose), AmR (Amino-Ribose), ThioR (Thio-ribose), HNA (hexose nucleic acid), CeNA (cyclohexene nucleic acid), or MOR (Morpholino) sugar.

[0187] Those skilled in the art after reading the present disclosure will appreciate that various types of sugar modifications are known and can be utilized in accordance with the present disclosure. In some embodiments, a sugar modification is a 2’-modification (e.g., R2s). In some embodiments, a 2’-modification is 2’-F. In some embodiments, a 2’-modification is 2’-OR, wherein R is not hydrogen. In some embodiments, a 2’-modification is 2’-OR, wherein R is optionally substituted C1-6aliphatic. In some embodiments, a 2’- modification is 2’-OR, wherein R is optionally substituted C1-6alkyl. In some embodiments, a 2’-modification is 2’-OMe. In some embodiments, a 2’-modification is 2’-MOE. In some embodiments, a 2’-modification is −O−Lb− or −Lb−Lb− which connects the 2’-carbon of a sugar moiety to another carbon of a sugar moiety. In some embodiments, a 2’-modification is 2’−O−Lb−4’ or 2’−Lb−Lb−4’ which connects the 2’-carbon of a sugar moiety to the 4’-carbon of a sugar moiety. In some embodiments, a 2’-modification is S-cEt. In some embodiments, a modified sugar is an LNA sugar. In some embodiments, −Lb− is −C(R)2−. In someembodiments, a 2’-modification is (C2−O−C(R)2−C4), wherein each R is independently as described in the present disclosure. In some embodiments, a 2’-modification is a LNA sugar modification (C2−O−CH2−C4). In some embodiments, a 2’-modification is (C2−O−CHR−C4), wherein R is as described in the present disclosure. In some embodiments, a 2’-modification is (C2−O−(R)-CHR−C4), wherein R is as described in the present disclosure and is not hydrogen. In some embodiments, a 2’-modification is (C2−O−(S)-CHR−C4), wherein R is as described in the present disclosure and is not hydrogen. In some embodiments, R is optionally substituted C1-6 aliphatic. In some embodiments, R is optionally substituted C1-6 alkyl. In some embodiments, R is unsubstituted C1-6 alkyl. In some embodiments, R is methyl. In some embodiments, R is ethyl. In some embodiments, a 2’-modification is (C2−O−CHR−C4), wherein R is optionally substituted C1-6 aliphatic. In some embodiments, a 2’-modification is (C2−O−CHR−C4), wherein R is optionally substituted C1-6 alkyl. In some embodiments, a 2’-modification is (C2−O−CHR−C4), wherein R is methyl. In some embodiments, a 2’-modification is (C2−O−CHR−C4), wherein R is ethyl. In some embodiments, a 2’-modification is (C2−O−(R)-CHR−C4), wherein R is optionally substituted C1-6aliphatic. In some embodiments, a 2’- modification is (C2−O−(R)-CHR−C4), wherein R is optionally substituted C1-6alkyl. In some embodiments, a 2’-modification is (C2−O−(R)-CHR−C4), wherein R is methyl. In some embodiments, a 2’-modification is (C2−O−(R)-CHR−C4), wherein R is ethyl. In some embodiments, a 2’-modification is (C2−O−(S)-CHR−C4), wherein R is optionally substituted C1-6aliphatic. In some embodiments, a 2’-modification is (C2−O−(S)- CHR−C4), wherein R is optionally substituted C1-6alkyl. In some embodiments, a 2’-modification is (C2−O−(S)-CHR−C4), wherein R is methyl. In some embodiments, a 2’-modification is (C2−O−(S)- CHR−C4), wherein R is ethyl. In some embodiments, a 2’-modification is C2−O−(R)-CH(CH2CH3)−C4. In some embodiments, a 2’-modification is C2−O−(S)-CH(CH2CH3)−C4. In some embodiments, a sugar is a natural DNA sugar. In some embodiments, a sugar is a natural RNA sugar. In some embodiments, a sugar is an optionally substituted natural DNA sugar. In some embodiments, a sugar is a natural DNA sugar optionally substituted at 2’. In some embodiments, a sugar is a natural DNA sugar substituted at 2’ (2’-modification). In some embodiments, a sugar is a natural DNA sugar modified at 2’ (2’-modification).

[0188] In some embodiments, a sugar is an optionally substituted ribose or deoxyribose. In some embodiments, a sugar is an optionally modified ribose or deoxyribose, wherein one or more hydroxyl groups of the ribose or deoxyribose moiety is optionally and independently replaced by halogen, R’, –N(R’)2, –OR’, or –SR’, wherein each R’ is as described herein. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with halogen, R’, –N(R’)2, –OR’, or –SR’, wherein each R’ is independently described in the present disclosure. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with halogen. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with one or more –F. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ positionof the deoxyribose is optionally substituted with –OR’, wherein each R’ is independently described in the present disclosure. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with –OR’, wherein each R’ is independently optionally substituted C1–C6 aliphatic. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with –OR’, wherein each R’ is independently an optionally substituted C1–C6 alkyl. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with –OMe. In some embodiments, a sugar is an optionally substituted deoxyribose, wherein the 2’ position of the deoxyribose is optionally substituted with –O–methoxyethyl.

[0189] In some embodiments, provided oligonucleotides comprise one or more modified sugars. In some embodiments, provided oligonucleotides comprise one or more modified sugars and one or more natural sugars.

[0190] Examples of bicyclic sugars include sugars of alpha-L-methyleneoxy (4'-CH2-O-2’) LNA, beta- D-methyleneoxy (4'-CH2-O-2’) LNA, ethyleneoxy (4' -(CH2)2-O-2’) LNA, aminooxy (4' -CH2-O-N(R)-2’) LNA, and oxyamino (4'-CH2-N(R)-O-2’) LNA. In some embodiments, a bicyclic sugar, e.g., a LNA or BNA sugar, is sugar having at least one bridge between two sugar carbons. In some embodiments, a bicyclic sugar in a nucleoside may have the stereochemical configurations of alpha-L-ribofuranose or beta-D-ribofuranose.

[0191] In some embodiments, a bicyclic sugar may be further defined by isomeric configuration. For example, a sugar comprising a 4’-(CH2)-O-2’ bridge may be in the alpha-L configuration or in the beta-D configuration. In some embodiments, a 4’ to 2’ bridge is a -L-4’-(CH2)-O-2’, b-D-4'-CH2-O-2’, 4'-(CH2)2-O- 2’, 4'-CH2-O-N(R’)-2’, 4'-CH2-N(R’)-O-2’, 4'-CH(R’)-O-2’, 4'-CH(CH3)-O-2’, 4'-CH2-S-2’, 4'-CH2-N(R’)-2’, 4'-CH2-CH(R’)-2’, 4'-CH2-CH(CH3)-2’, and 4'-(CH2)3-2’, wherein each R’ is as described in the present disclosure. In some embodiments, R’ is −H, a protecting group or optionally substituted C1-C12alkyl. In some embodiments, R’ is −H or optionally substituted C1-C12alkyl.

[0192] In some embodiments, a bicyclic sugar is a sugar of alpha-L-methyleneoxy (4'-CH2-O-2’) BNA, beta-D-methyleneoxy (4'-CH2-O-2’) BNA, ethyleneoxy (4'-(CH2)2-O-2’) BNA, aminooxy (4'-CH2-O-N(R)- 2’) BNA, oxyamino (4'-CH2-N(R)-O-2’) BNA, methyl(methyleneoxy) (4'-CH(CH3)-O-2’) BNA (also referred to as constrained ethyl or cEt), methylene-thio (4'-CH2-S-2’) BNA, methylene-amino (4'-CH2-N(R)-2’) BNA, methyl carbocyclic (4'-CH2-CH(CH3)-2’) BNA, propylene carbocyclic (4'-(CH2)3-2’) BNA, or vinyl BNA.

[0193] In some embodiments, a sugar modification is a modification described in US 9006198. In some embodiments, a modified sugar is described in US 9006198. In some embodiments, a sugar modification is a modification described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858,and / or WO 2022 / 099159, the sugar modifications and modified sugars of each of which are independently incorporated herein by reference.

[0194] In some embodiments a modified sugar is one described in US 5658873, US 5118800, US 5393878, US 5514785, US 5627053, US 7034133;7084125, US 7399845, US 5319080, US 5591722, US 5597909, US 5466786, US 6268490, US 6525191, US 5519134, US 5576427, US 6794499, US 6998484, US 7053207, US 4981957, US 5359044, US 6770748, US 7427672, US 5446137, US 6670461, US 7569686, US 7741457, US 8022193, US 8030467, US 8278425, US 5610300, US 5646265, US 8278426, US 5567811, US 5700920, US 8278283, US 5639873, US 5670633, US 8314227, US 2008 / 0039618, US 2009 / 0012281, WO 2021 / 030778, WO 2020 / 154344, WO 2020 / 154343, WO 2020 / 154342, WO 2020 / 165077, WO 2020 / 201406, WO 2020 / 216637, or WO 2020 / 252376.

[0195] In some embodiments, a sugar modification is 2’-OMe, 2’-MOE, 2’-LNA, 2’-F, 5’-vinyl, or S- cEt. In some embodiments, a modified sugar is a sugar of FRNA, FANA, or morpholino. In some embodiments, an oligonucleotide comprises a nucleic acid analog, e.g., GNA, LNA, PNA, TNA, F-HNA (F- THP or 3’-fluoro tetrahydropyran), MNA (mannitol nucleic acid, e.g., Leumann 2002 Bioorg. Med. Chem.10: 841-854), ANA (anitol nucleic acid), or morpholino, or a portion thereof. In some embodiments, a sugar is as in flexible nucleic acids or serinol nucleic acids. In some embodiments, a sugar modification replaces a natural sugar with another cyclic or acyclic moiety. Examples of such moieties are widely known in the art, e.g., those used in morpholino, glycol nucleic acids, etc. and may be utilized in accordance with the present disclosure. As appreciated by those skilled in the art, when utilized with modified sugars, in some embodiments internucleotidic linkages may be modified, e.g., as in morpholino, PNA, etc. In some embodiments, a sugar is a (R)-GNA sugar. In some embodiments, a sugar is a (S)-GNA sugar. In some embodiments, a sugar is bicyclic sugar. In some embodiments, a sugar is a LNA sugar. In some embodiments, a sugar is an acyclic sugar. In some embodiments, a sugar is a UNA sugar. In some embodiments, a nucleoside is abasic.

[0196] In some embodiments, a sugar is a 6’-modified bicyclic sugar that have either (R) or (S)-chirality at the 6-position, e.g., those described in US 7399845. In some embodiments, a sugar is a 5’-modified bicyclic sugar that has either (R) or (S)-chirality at the 5-position, e.g., those described in US 20070287831.

[0197] In some embodiments, a modified sugar contains one or more substituents at the 2’ position (typically one substituent, and often at the axial position) independently selected from –F; –CF3, –CN, –N3, – NO, –NO2, –OR’, –SR’, or –N(R’)2, wherein each R’ is independently described in the present disclosure; – O–(C1–C10alkyl), –S–(C1–C10alkyl), –NH–(C1–C10alkyl), or –N(C1–C10alkyl)2; –O–(C2–C10alkenyl), –S– (C2–C10alkenyl), –NH–(C2–C10alkenyl), or –N(C2–C10alkenyl)2; –O–(C2–C10alkynyl), –S–(C2–C10alkynyl), –NH–(C2–C10 alkynyl), or –N(C2–C10 alkynyl)2; or –O––(C1–C10 alkylene)–O––(C1–C10 alkyl), –O–(C1–C10 alkylene)–NH–(C1–C10alkyl) or –O–(C1–C10alkylene)–NH(C1–C10alkyl)2, –NH–(C1–C10alkylene)–O–(C1– C10alkyl), or –N(C1–C10alkyl)–(C1–C10alkylene)–O–(C1–C10alkyl), wherein each of the alkyl, alkylene, alkenyl and alkynyl is independently and optionally substituted. In some embodiments, a substituent is – O(CH2)nOCH3, –O(CH2)nNH2, MOE, DMAOE, or DMAEOE, wherein n is from 1 to about 10. In someembodiments, a modified sugar is one described in WO 2001 / 088198; and Martin et al., Helv. Chim. Acta, 1995, 78, 486-504. In some embodiments, a modified sugar comprises one or more groups selected from a substituted silyl group, an RNA cleaving group, a reporter group, a fluorescent label, an intercalator, a group for improving the pharmacokinetic properties of a nucleic acid, a group for improving the pharmacodynamic properties of a nucleic acid, or other substituents having similar properties. In some embodiments, modifications are made at one or more of the 2’, 3’, 4’, or 5’ positions, including the 3’ position of the sugar on the 3’-terminal nucleoside or in the 5’ position of the 5’-terminal nucleoside.

[0198] In some embodiments, the 2’-OH of a ribose is replaced with a group selected from –H, –F; –CF3, –CN, –N3, –NO, –NO2, –OR’, –SR’, or –N(R’)2, wherein each R’ is independently described in the present disclosure; –O–(C1–C10 alkyl), –S–(C1–C10 alkyl), –NH–(C1–C10 alkyl), or –N(C1–C10 alkyl)2; –O–(C2–C10 alkenyl), –S–(C2–C10 alkenyl), –NH–(C2–C10 alkenyl), or –N(C2–C10 alkenyl)2; –O–(C2–C10 alkynyl), –S–(C2– C10 alkynyl), –NH–(C2–C10 alkynyl), or –N(C2–C10 alkynyl)2; or –O–(C1–C10 alkylene)–O––(C1–C10 alkyl), – O–(C1–C10alkylene)–NH–(C1–C10alkyl) or –O–(C1–C10alkylene)–NH(C1–C10alkyl)2, –NH–(C1–C10alkylene)–O–(C1–C10alkyl), or –N(C1–C10alkyl)–(C1–C10alkylene)–O–(C1–C10alkyl), wherein each of the alkyl, alkylene, alkenyl and alkynyl is independently and optionally substituted. In some embodiments, the 2’–OH is replaced with –H (deoxyribose). In some embodiments, the 2’–OH is replaced with –F. In some embodiments, the 2’–OH is replaced with –OR’. In some embodiments, the 2’–OH is replaced with –OMe. In some embodiments, the 2’–OH is replaced with –OCH2CH2OMe.

[0199] In some embodiments, a sugar modification is a 2’-modification. Commonly used 2’- modifications include but are not limited to 2’–OR, wherein R is not hydrogen and is as described in the present disclosure. In some embodiments, a modification is 2’−OR, wherein R is optionally substituted C1-6aliphatic. In some embodiments, a modification is 2’−OR, wherein R is optionally substituted C1-6alkyl. In some embodiments, a modification is 2’−OMe. In some embodiments, a modification is 2’-MOE. In some embodiments, a 2’-modification is S-cEt. In some embodiments, a modified sugar is an LNA sugar. In some embodiments, a 2’-modification is −F. In some embodiments, a 2’-modification is FANA. In some embodiments, a 2’-modification is FRNA. In some embodiments, a sugar modification is a 5’-modification, e.g., 5’-Me. In some embodiments, a sugar modification changes the size of the sugar ring. In some embodiments, a sugar modification is the sugar moiety in FHNA.

[0200] In some embodiments, a sugar modification replaces a sugar moiety with another cyclic or acyclic moiety. Examples of such moieties are widely known in the art, including but not limited to those used in morpholino (optionally with its phosphorodiamidate linkage), glycol nucleic acids, etc.

[0201] In some embodiments, one or more of the sugars of an oligonucleotide are modified. In some embodiments, a modified sugar comprises a 2’-modification. In some embodiments, each modified sugar independently comprises a 2’-modification. In some embodiments, a 2’-modification is 2’-OR. In some embodiments, a 2’-modification is a 2’-OMe. In some embodiments, a 2’-modification is a 2’-MOE. In some embodiments, a 2’-modification is an LNA sugar modification. In some embodiments, a 2’-modification is2’-F. In some embodiments, each sugar modification is independently a 2’-modification. In some embodiments, each sugar modification is independently 2’-OR or 2’-F. In some embodiments, each sugar modification is independently 2’-OR or 2’-F, wherein R is optionally substituted C1-6 alkyl. In some embodiments, each sugar modification is independently 2’-OR or 2’-F, wherein at least one is 2’-F. In some embodiments, each sugar modification is independently 2’-OR or 2’-F, wherein R is optionally substituted C1- 6 alkyl, and wherein at least one is 2’-OR. In some embodiments, each sugar modification is independently 2’-OR or 2’-F, wherein at least one is 2’-F, and at least one is 2’-OR. In some embodiments, each sugar modification is independently 2’-OR or 2’-F, wherein R is optionally substituted C1-6 alkyl, and wherein at least one is 2’-F, and at least one is 2’-OR. In some embodiments, each sugar modification is independently 2’-OR. In some embodiments, each sugar modification is independently 2’-OR, wherein R is optionally substituted C1-6 alkyl. In some embodiments, each sugar modification is 2’-OMe. In some embodiments, each sugar modification is 2’-MOE. In some embodiments, each sugar modification is independently 2’-OMe or 2’-MOE. In some embodiments, each sugar modification is independently 2’-OMe, 2’-MOE, or a LNA sugar.

[0202] Modified sugars include cyclobutyl or cyclopentyl moieties in place of a pentofuranosyl sugar. Representative examples of such modified sugars include those described in US 4,981,957, US 5,118,800, US 5,319,080, or US 5,359,044. In some embodiments, the oxygen atom within the ribose ring is replaced by nitrogen, sulfur, selenium, or carbon. In some embodiments, −O− is replaced with −N(R’)−, −S−, −Se− or −C(R’)2−. In some embodiments, a modified sugar is a modified ribose wherein the oxygen atom within the ribose ring is replaced with nitrogen, and wherein the nitrogen is optionally substituted with an alkyl group (e.g., methyl, ethyl, isopropyl, etc.).

[0203] A non-limiting example of modified sugars is glycerol, which is part of glycerol nucleic acids (GNAs), e.g., as described in Zhang, R et al., J. Am. Chem. Soc., 2008, 130, 5846-5847; Zhang L, et al., J. Am. Chem. Soc., 2005, 127, 4174-4175 and Tsai CH et al., PNAS, 2007, 14598-14603.

[0204] A flexible nucleic acid (FNA) is based on a mixed acetal aminal of formyl glycerol, e.g., as described in Joyce GF et al., PNAS, 1987, 84, 4398-4402 and Heuberger BD and Switzer C, J. Am. Chem. Soc., 2008, 130, 412-413.

[0205] In some embodiments, an oligonucleotide, and / or a modified nucleoside thereof, comprises a sugar or modified sugar described in: WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the sugars and modified sugars of each of which are independently incorporated herein by reference.

[0206] In some embodiments, one or more hydroxyl group in a sugar is optionally and independently replaced with halogen, R’ –N(R’)2, –OR’, or –SR’, wherein each R’ is independently described in the present disclosure.

[0207] In some embodiments, a modified nucleoside is any modified nucleoside described in: WO2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the modified nucleosides of each of which are independently incorporated herein by reference.

[0208] In some embodiments, a sugar modification is 5’-vinyl (R or S), 5’-methyl (R or S), 2'-SH, 2’-F, 2’-OCH3, 2’-OCH2CH3, 2’-OCH2CH2F or 2’-O(CH2)20CH3. In some embodiments, a substituent at the 2’ position, e.g., a 2’-modification, is allyl, amino, azido, thio, O-allyl, O-C1-C10 alkyl, OCF3, OCH2F, O(CH2)2SCH3, O(CH2)2-O-N(Rm)(Rn), O-CH2-C(=O)-N(Rm)(Rn), and O-CH2-C(=O)-N(R1)-(CH2)2- N(Rm)(Rn), wherein each allyl, amino and alkyl is optionally substituted, and each of Rl, Rm and Rn is independently R’ as described in the present disclosure. In some embodiments, each of Rl, Rm and Rn is independently −H or optionally substituted C1-C10 alkyl.

[0209] In some embodiments, bicyclic sugars comprise a bridge, e.g., −Lb−Lb−, −L−, etc. between two sugar carbons, e.g., between the 4’ and the 2’ ribosyl ring carbon atoms. In some embodiments, a bridge is 4'−(CH2)−O−2’ (e.g., LNA sugars), 4'−(CH2)−S−2’, 4’−(CH2)2−O−2’ (e.g., ENA sugars), 4’−CH(R’)−O−2’ (e.g., 4’−CH(CH3)−O−2’, 4’−CH(CH2OCH3)−O−2’, and examples in US 7399845, etc.), 4’−CH(R’)2−O−2’ (e.g., 4’−C(CH3)(CH3)−O−2’ and examples in WO 2009006478, etc.), 4’-CH2-N(OR’)-2’ (e.g., 4’-CH2- N(OCH3)-2’, examples in WO 2008150729, etc.), 4’−CH2−O−N(R’)−2’ (e.g., 4’−CH2−O−N(CH3)−2’, examples in US 20040171570, etc.), 4’−CH2−N(R’)−O−2’ [e.g., wherein R is −H, C1-C12alkyl, or a protecting group (e.g., see US 7427672)], 4’−C(R’)2−C(H)(R’)−2’ (e.g., 4'−CH2−C(H)(CH3)−2’, examples in Chattopadhyaya et al., J. Org. Chem., 2009, 74, 118-134, etc.), or 4’−C(R’)2−C(=C(R’)2)−2’ (e.g., 4’−CH2−C(=CH2)−2’, examples in WO 2008154401, etc.).

[0210] In some embodiments, a sugar is a tetrahydropyran or THP sugar. In some embodiments, a modified nucleoside is tetrahydropyran nucleoside or THP nucleoside which is a nucleoside having a six- membered tetrahydropyran sugar substituted for a pentofuranosyl residue in typical natural nucleosides. THP sugars and / or nucleosides include those used in hexitol nucleic acid (HNA), anitol nucleic acid (ANA), mannitol nucleic acid (MNA) (e.g., Leumann, Bioorg. Med. Chem., 2002, 10, 841-854) or fluoro HNA (F- HNA).

[0211] In some embodiments, sugars comprise rings having more than 5 atoms and / or more than one heteroatom, e.g., morpholino sugars which are described in e.g., Braasch et al., Biochemistry, 2002, 41, 4503- 4510; US 5698685; US 5166315; US 5185444; US 5034506; etc.).

[0212] As those skilled in the art will appreciate, modifications of sugars, nucleobases, internucleotidic linkages, etc. can and are often utilized in combination in oligonucleotides, e.g., see various oligonucleotides in Table 1.

[0213] In some embodiments, a nucleoside has a six-membered cyclohexenyl in place of the pentofuranosyl residue in naturally occurring nucleosides. Example cyclohexenyl nucleosides and preparation and uses thereof are described in, e.g., WO 2010036696; Robeyns et al., J. Am. Chem. Soc., 2008, 130(6),1979-1984; Horvath et al., Tetrahedron Letters, 2007, 48, 3621-3623; Nauwelaerts et al., J. Am. Chem. Soc., 2007, 129(30), 9340-9348; Gu et al., Nucleosides, Nucleotides & Nucleic Acids, 2005, 24(5-7), 993-998; Nauwelaerts et al., Nucleic Acids Research, 2005, 33(8), 2452-2463; Robeyns et al., Acta Crystallographica, Section F: Structural Biology and Crystallization Communications, 2005, F61(6), 585-586; Gu et al., Tetrahedron, 2004, 60(9), 2111-2123; Gu et al., Oligonucleotides, 2003, 13(6), 479-489; Wang et al., J. Org. Chem., 2003, 68, 4499-4505; Verbeure et al., Nucleic Acids Research, 2001, 29(24), 4941-4947; Wang et al., J. Org. Chem., 2001, 66, 8478-82; Wang et al., Nucleosides, Nucleotides & Nucleic Acids, 2001, 20(4-7), 785- 788; Wang et al., J. Am. Chem., 2000, 122, 8595-8602; WO 2006047842; WO 2001049687; etc.

[0214] Many monocyclic, bicyclic and tricyclic ring systems are suitable as sugar surrogates (modified sugars) and may be utilized in accordance with the present disclosure. See, e.g., Leumann, Christian J. Bioorg. & Med. Chem., 2002, 10, 841-854. Such ring systems can undergo various additional substitutions to further enhance their properties and / or activities.

[0215] In some embodiments, a 2’-modified sugar is a furanosyl sugar modified at the 2’ position. In some embodiments, a 2’-modification is halogen, −R’ (wherein R’ is not −H), −OR’ (wherein R’ is not −H), −SR’, −N(R’)2, optionally substituted −CH2−CH=CH2, optionally substituted alkenyl, or optionally substituted alkynyl. In some embodiments, a 2’-modifications is selected from −O[(CH2)nO]mCH3, −O(CH2)nNH2, −O(CH2)nCH3, −O(CH2)nF, −O(CH2)nONH2, −OCH2C(=O)N(H)CH3, and −O(CH2)nON[(CH2)nCH3]2, wherein each n and m is independently from 1 to about 10. In some embodiments, a 2’-modification is optionally substituted C1-C12alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkaryl, optionally substituted aralkyl, optionally substituted −O−alkaryl, optionally substituted −O−aralkyl, −SH, −SCH3, −OCN, −Cl, −Br, −CN, −F, −CF3, −OCF3, −SOCH3, −SO2CH3, −ONO2, −NO2, −N3, −NH2, optionally substituted heterocycloalkyl, optionally substituted heterocycloalkaryl, optionally substituted aminoalkylamino, optionally substituted polyalkylamino, substituted silyl, a reporter group, an intercalator, a group for improving pharmacokinetic properties, a group for improving the pharmacodynamic properties, and other substituents. In some embodiments, a 2’-modification is a 2’-MOE modification (e.g., see Baker et al., J. Biol. Chem., 1997, 272, 11944-12000). In some cases, a 2’-MOE modification has been reported as having improved binding affinity compared to unmodified sugars and to some other modified nucleosides, such as 2’- O-methyl, 2’-O-propyl, and 2’-O-aminopropyl. Oligonucleotides having the 2’-MOE modification have also been reported to be capable of inhibiting gene expression with promising features for in vivo use (see, e.g., Martin, Helv. Chim. Acta, 1995, 78, 486-504; Altmann et al., Chimia, 1996, 50, 168- 176; Altmann et al., Biochem. Soc. Trans., 1996, 24, 630-637; and Altmann et al., Nucleosides Nucleotides, 1997, 16, 917-926; etc.).

[0216] In some embodiments, a 2’-modified or 2’-substituted sugar or nucleoside is a sugar or nucleoside comprising a substituent at the 2’ position of the sugar which is other than −H (typically not considered a substituent) or −OH. In some embodiments, a 2’-modified sugar is a bicyclic sugar comprising a bridge connecting two carbon atoms of the sugar ring one of which is the 2’ carbon. In some embodiments, a 2’-modification is non-bridging, e.g., allyl, amino, azido, thio, optionally substituted −O−allyl, optionally substituted −O−C1-C10 alkyl, −OCF3, −O(CH2)2OCH3, 2’-O(CH2)2SCH3, −O(CH2)2ON(Rm)(Rn), or −OCH2C(=O)N(Rm)(Rn), where each Rm and Rn is independently −H or optionally substituted C1-C10 alkyl.

[0217] Certain modified sugars, their preparation and uses are described in US 4981957, US 5118800, US 5319080, US 5359044, US 5393878, US 5446137, US 5466786, US 5514785, US 5519134, US 5567811, US 5576427, US 5591722, US 5597909, US 5610300, US 5627053, US 5639873, US 5646265, US 5670633, US 5700920, US 5792847, US 6600032 and WO 2005121371.

[0218] In some embodiments, a sugar is the sugar of N-methanocarba, LNA, cMOE BNA, cEt BNA, a- L-LNA or related analogs, HNA, Me-ANA, MOE-ANA, Ara-FHNA, FHNA, R-6'-Me-FHNA, S-6'-Me- FHNA, ENA, or c-ANA. In some embodiments, a modified internucleotidic linkage is C3-amide (e.g., sugar that has the amide modification attached to the C3’, Mutisya et al. 2014 Nucleic Acids Res. 2014 Jun 1; 42(10): 6542–6551), formacetal, thioformacetal, MMI [e.g., methylene(methylimino), Peoc'h et al. 2006 Nucleosides and Nucleotides 16 (7-9)], a PMO (phosphorodiamidate linked morpholino) linkage (which connects two sugars), or a PNA (peptide nucleic acid) linkage. In some embodiments, examples of internucleotidic linkages and / or sugars are described in Allerson et al.2005 J. Med. Chem.48: 901-4; BMCL 201121: 1122; BMCL 201121: 588; BMCL 201222: 296; Chattopadhyaya et al. 2007 J. Am. Chem. Soc. 129: 8362; Chem. Bio. Chem.201314: 58; Curr. Prot. Nucl. Acids Chem.20111.24.1; Egli et al.2011 J. Am. Chem. Soc.133: 16642; Hendrix et al. 1997 Chem. Eur. J.3: 110; Hyrup et al.1996 Bioorg. Med. Chem.4: 5; Imanishi 1997 Tet. Lett.38: 8735; J. Am. Chem. Soc.1994, 116, 3143; J. Med. Chem.200952: 10; J. Org. Chem.201075: 1589; Jepsen et al.2004 Oligo.14: 130-146; Jones et al. J. Org. Chem.1993, 58, 2983; Jung et al.2014 ACIEE 53: 9893; Kodama et al.2014 AGDS; Koizumi 2003 BMC 11: 2211; Koizumi et al.2003 Nuc. Acids Res. 12: 3267-3273; Koshkin et al. 1998 Tetrahedron 54: 3607-3630; Kumar et al. 1998 Bioo. Med. Chem. Let. 8: 2219-2222; Lauritsen et al.2002 Chem. Comm.5: 530-531; Lauritsen et al.2003 Bioo. Med. Chem. Lett.13: 253-256; Lima et al.2012 Cell 150: 883-894; Mesmaeker et al. Angew. Chem., Int. Ed. Engl.1994, 33, 226; Migawa et al. 2013 Org. Lett.15: 4316; Mol. Ther. Nucl. Acids 20121: e47; Morita et al. 2001 Nucl. Acids Res. Supp. 1: 241-242; Morita et al.2002 Bioo. Med. Chem. Lett. 12: 73-76; Morita et al.2003 Bioo. Med. Chem. Lett.2211-2226; Murray et al.2012 Nucl. Acids Res.40: 6135; Nielsen et al.1997 Chem. Soc. Rev. 73; Nielsen et al. 1997 J. Chem. Soc. Perkins Transl. 1: 3423-3433; Obika et al. 1997 Tetrahedron Lett. 38 (50): 8735–8; Obika et al. 1998 Tetrahedron Lett. 39: 5401-5404; Obika et al. 2008 J. Am. Chem. Soc. 130: 4886; Obika et al. 2011 Org. Lett. 13: 6050; Oestergaard et al. 2014 JOC 79: 8877; Pallan et al. 2012 Biochem. 51: 7; Pallan et al. 2012 Chem. Comm. 48: 8195-8197; Petersen et al. 2003 TRENDS Biotech. 21: 74-81; Prakash et al. 2010 J. Med. Chem.53: 1636; Prakash et al.2015 Nucl. Acids Res.43: 2993-3011; Prakash et al.2016 Bioorg. Med. Chem. Lett.26: 2817-2820; Rajwanshi et al.1999 Chem. Commun.1395-1396; Schultz et al.1996 Nucleic Acids Res.24: 2966; Seth et al.2008 Nucl. Acid Sym. Ser. 52: 553; Seth et al.2009 J. Med. Chem.52: 10-13; Seth et al.2010 J. Am. Chem. Soc.132: 14942; Seth et al.2010 J. Med. Chem.53: 8309-8318; Seth et al.2010 J. Org. Chem.75: 1569-1581; Seth et al.2011 BMCL 21: 4690; Seth et al. 2012 Bioo. Med. Chem. Lett. 22: 296-299; Seth et al. 2012 Mol. Ther-Nuc. Acids. 1, e47; Seth et al., Nucleic Acids Symposium Series (2008), 52(1), 553-554; Singh et al.1998 Chem. Comm.1247- 1248; Singh et al.1998 J. Org. Chem.63: 10035-39; Singh et al.1998 J. Org. Chem.63: 6078-6079; Sorensen 2003 Chem. Comm. 2130-2131; Starrup et al. 2010 Nucl. Acids Res. 38: 7100; Swayze et al. 2007 Nucl. Acids Res.35: 687; Ts'o et al. Ann. N. Y. Acad. Sci.1988, 507, 220; Van Aerschot et al.1995 Angew. Chem. Int. Ed. Engl.34: 1338; Vasseur et al. J. Am. Chem. Soc.1992, 114, 4006; WO 2007090071; WO 2016079181; US 6326199; US 6066500; or US 6440739.

[0219] In some embodiments, an oligonucleotide or a portion thereof (e.g., a domain, a subdomain, etc.) comprises a high level of 2’-F modified sugars, e.g., about 10%-100% (e.g., about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more, or about 100%) of sugars in an oligonucleotide or a portion thereof (e.g., a domain, a subdomain, etc.) comprises 2’-F. In some embodiments, about 50% or more of sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, about 60% or more of sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, about 70% or more of sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, about 80% or more of sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, about 90% or more of sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, about 1-20 or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or more) sugars in an oligonucleotide or a portion thereof (e.g., a domain, a subdomain, etc.) comprises 2’-F. In some embodiments, 1 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 2 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 3 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 4 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 5 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 6 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 7 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 8 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 9 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 10 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 11 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 12 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 13 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 14 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 15 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 16 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 17 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In someembodiments, 18 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 19 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, 20 or more sugars in an oligonucleotide or a portion thereof comprises 2’-F. In some embodiments, an oligonucleotide or a portion thereof also comprises one or more sugars comprising no 2’-F (e.g., sugars comprising no modifications and / or sugars comprising other modifications).

[0220] In some embodiments, no more than about 1%-95% (e.g., no more than about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc.) of sugars in an oligonucleotide or a portion thereof (e.g., a domain, a subdomain, etc.) comprises 2’-OMe. In some embodiments, no more than about 50% of sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 1, 2, 3, 4, or 5 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 1 sugar in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 2 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 3 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 4 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe. In some embodiments, no more than 5 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe.

[0221] In some embodiments, about 1-20 or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or more) sugars in an oligonucleotide or a portion thereof (e.g., a domain, a subdomain, etc.) comprises 2’-F and no more than 1, 2, 3, 4, or 5 sugars in an oligonucleotide or a portion thereof comprises 2’-OMe.

[0222] Various additional sugars useful for preparing oligonucleotides or analogs thereof are known in the art and may be utilized in accordance with the present disclosure. Internucleotidic linkages

[0223] Among other things, the present disclosure provides various internucleotidic linkages, including various modified internucleotidic linkages, that may be utilized together with other structural elements, e.g., various sugars as described herein, to provide oligonucleotides and compositions thereof.

[0224] In some embodiments, oligonucleotides comprise base modifications, sugar modifications, and / or internucleotidic linkage modifications. Various internucleotidic linkages can be utilized in accordance with the present disclosure to link units comprising nucleobases, e.g., nucleosides. In some embodiments, provided oligonucleotides comprise both one or more modified internucleotidic linkages and one or more natural phosphate linkages. In some embodiments, an oligonucleotide comprises one or more types of internucleotidic linkage. In some embodiments, an oligonucleotide comprises two or more types of internucleotidic linkage. In some embodiments, an oligonucleotide comprises at least three types of internucleotidic linkages. In some embodiments, a linkage contains a linkage phosphorus atom bonded to an oxygen atom which oxygen atom is not bonded to or is not part of a backbone sugar (“a PO linkage”, e.g., a natural phosphate linkage). In someembodiments, a linkage contains a linkage phosphorus atom bonded to a sulfur atom which sulfur atom is not bonded to or is not part of a backbone sugar (“a PS linkage”, e.g., a phosphorothioate internucleotidic linkage). In some embodiments, a linkage contains a linkage phosphorus atom bonded to a nitrogen atom which nitrogen atom is not bonded to or is not part of a backbone sugar (“a PN linkage”, e.g., n001). In some embodiments, an oligonucleotide comprises one or more PS linkages. In some embodiments, an oligonucleotide comprises one or more PO linkages. In some embodiments, an oligonucleotide comprises one or more PN linkages. In some embodiments, an oligonucleotide comprises one or more PS and one or more PO linkages. In some embodiments, an oligonucleotide comprises one or more PS and one or more PN linkages. In some embodiments, an oligonucleotide comprises one or more PS, one or more PN and one or more PO linkages. In some embodiments, a PS linkage is a phosphorothioate linkage. In some embodiments, each PS linkage is independently a phosphorothioate linkage. In some embodiments, a PO linkage is a natural phosphate linkage. In some embodiments, each PO linkage is independently a natural phosphate linkage. In some embodiments, a PN linkage is a phosphoryl guanidine linkage. In some embodiments, each PN linkage is independently a phosphoryl guanidine linkage.

[0225] As widely known by those skilled in the art, natural phosphate linkages are widely found in natural DNA and RNA molecules; they have the structure of −OP(O)(OH)O−, connect sugars in the nucleosides in DNA and RNA, and may be in various salt forms, for example, at physiological pH (about 7.4), natural phosphate linkages are predominantly exist in salt forms with the anion being −OP(O)(O−)O−. A modified internucleotidic linkage, or a non-natural phosphate linkage, is an internucleotidic linkage that is not natural phosphate linkage or a salt form thereof. Modified internucleotidic linkages, depending on their structures, may also be in their salt forms. For example, as appreciated by those skilled in the art, phosphorothioate internucleotidic linkages which have the structure of −OP(O)(SH)O− may be in various salt forms, e.g., at physiological pH (about 7.4) with the anion being −OP(O)(S−)O−.

[0226] In some embodiments, an oligonucleotide comprises an internucleotidic linkage which is a modified internucleotidic linkage, e.g., phosphorothioate, phosphorodithioate, methylphosphonate, phosphoroamidate, thiophosphate, 3’-thiophosphate, or 5’-thiophosphate. In some embodiments, a modified internucleotidic linkage is a PN linkage. In some embodiments, a modified internucleotidic linkage is a PS linkage. In some embodiments, a modified internucleotidic linkage is a PO linkage (e.g., other than a natural phosphate linkage). In some embodiments, each modified internucleotidic linkage is independently a PN internucleotidic linkage or a PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises one or more PN internucleotidic linkages, one or more PS internucleotidic linkages, and one or more PO internucleotidic linkages. In some embodiments, one or more PN internucleotidic linkages are independently phosphoryl guanidine internucleotidic linkages. In some embodiments, one or more PN internucleotidic linkages are independently n001. In some embodiments, one or more PS internucleotidic linkages are independently phosphorothioate internucleotidic linkages. In some embodiments, each PS internucleotidic linkage is independently a phosphorothioate internucleotidic linkage. In some embodiments, one or more POinternucleotidic linkages are independently natural phosphate linkages. In some embodiments, each PO internucleotidic linkage is independently a natural phosphate linkage.

[0227] In some embodiments, a modified internucleotidic linkage is a chiral internucleotidic linkage which comprises a chiral linkage phosphorus. In some embodiments, a chiral internucleotidic linkage is a phosphorothioate linkage. In some embodiments, a chiral internucleotidic linkage is a non-negatively charged internucleotidic linkage. In some embodiments, a chiral internucleotidic linkage is a neutral internucleotidic linkage. In some embodiments, a chiral internucleotidic linkage is chirally controlled with respect to its chiral linkage phosphorus. In some embodiments, a chiral internucleotidic linkage is stereochemically pure with respect to its chiral linkage phosphorus. In some embodiments, a chiral internucleotidic linkage is not chirally controlled. In some embodiments, a pattern of backbone chiral centers comprises or consists of positions and linkage phosphorus configurations of chirally controlled internucleotidic linkages (Rp or Sp) and positions of achiral internucleotidic linkages (e.g., natural phosphate linkages).

[0228] In some embodiments, an internucleotidic linkage comprises a P-modification, wherein a P- modification is a modification at a linkage phosphorus. In some embodiments, a modified internucleotidic linkage is a moiety which does not comprise a phosphorus but serves to link two sugars or two moieties that each independently comprises a nucleobase, e.g., as in peptide nucleic acid (PNA).

[0229] In some embodiments, an oligonucleotide comprises a modified internucleotidic linkage, e.g., those having the structure of Formula I, I-a, I-b, or I-c and described herein and / or in: WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the internucleotidic linkages (e.g., those of Formula I, I-a, I-b, I-c, etc.) of each of which are independently incorporated herein by reference. In some embodiments, a modified internucleotidic linkage is a chiral internucleotidic linkage. In some embodiments, a modified internucleotidic linkage is a phosphorothioate internucleotidic linkage.

[0230] In some embodiments, a modified internucleotidic linkage is a non-negatively charged internucleotidic linkage. In some embodiments, provided oligonucleotides comprise one or more non- negatively charged internucleotidic linkages. In some embodiments, a non-negatively charged internucleotidic linkage is a positively charged internucleotidic linkage. In some embodiments, a non-negatively charged internucleotidic linkage is a neutral internucleotidic linkage. In some embodiments, the present disclosure provides oligonucleotides comprising one or more neutral internucleotidic linkages. In some embodiments, a non-negatively charged internucleotidic linkage has the structure of Formula I-n-1, I-n-2, I-n-3, I-n-4, II, II-a- 1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc., or a salt form thereof, as described herein and / or in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185,WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, and / or WO 2022 / 099159, the non- negatively charged internucleotidic linkages (e.g., those of Formula I-n-1, I-n-2, I-n-3, I-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc., or a suitable salt form thereof) of each of which are independently incorporated herein by reference.

[0231] In some embodiments, a non-negatively charged internucleotidic linkage can improve the delivery and / or activities (e.g., exon skipping activity).

[0232] In some embodiments, a modified internucleotidic linkage (e.g., a non-negatively charged internucleotidic linkage) comprises optionally substituted triazolyl. In some embodiments, a modified internucleotidic linkage (e.g., a non-negatively charged internucleotidic linkage) comprises optionally substituted alkynyl. In some embodiments, a modified internucleotidic linkage comprises a triazole or alkyne moiety. In some embodiments, a triazole moiety, e.g., a triazolyl group, is optionally substituted. In some embodiments, a triazole moiety, e.g., a triazolyl group) is substituted. In some embodiments, a triazole moiety is unsubstituted. In some embodiments, a modified internucleotidic linkage comprises an optionally substituted cyclic guanidine moiety. In some embodiments, a modified internucleotidic linkage has the structure optionally chirally controlled, wherein R1is −L−R’, wherein L is LBas described herein, and R’ is as described herein. In some embodiments, each R1is independently R’. In some embodiments, each R’ is independently R. In some embodiments, two R1are R and are taken together to form a ring as described herein. In some embodiments, two R1on two different nitrogen atoms are R and are taken together to form a ring as described herein. In some embodiments, R1is independently optionally substituted C1-6 aliphatic as described herein. In some embodiments, R1is methyl. In some embodiments, two R’ on the same nitrogen atom are R and are taken together to form a ring as described herein. In some embodiments, aptionally chirally controlled. In some embodiments,In some embodiments, a modified internucleotidic linkage comprises an optionally substituted cyclic guanidine moiety and has the structure of:wherein W is O or S. In some embodiments, W is O. In some embodiments, W is S. In some embodiments, a non-negatively charged internucleotidic linkage is stereochemically controlled.

[0233] In some embodiments, a non-negatively charged internucleotidic linkage or a neutral internucleotidic linkage is an internucleotidic linkage comprising a triazole moiety. In some embodiments, a non-negatively charged internucleotidic linkage or a non-negatively charged internucleotidic linkage comprises an optionally substituted triazolyl group. In some embodiments, an internucleotidic linkage comprising a triazole moiety (e.g., an optionally substituted triazolyl group) has the structure of smoiety has the formula oIn some embodiments, an internucleotidic linkage comprising an alkyne moiety (e.g., an optionally substituted alkynyl group) has the formula owherein W is O or S. In some embodiments, an internucleotidic linkage, e.g., a non-negatively charged internucleotidic linkage, a neutral internucleotidic linkage, comprises a cyclic guanidine moiety. In some embodiments, an internucleotidic linkage comprising a cyclic guanidine moiety has the structure oIn some embodiments, a non-negatively charged internucleotidic linkage, or a neutral internucleotidic linkage, is or comprising a structure selected fromwherein W is O or S.

[0234] In some embodiments, an internucleotidic linkage comprises a Tmg group ( someembodiments, an internucleotidic linkage comprises a Tmg group and has the structure of(the “Tmg internucleotidic linkage”). In some embodiments, neutral internucleotidic linkages include internucleotidic linkages of PNA and PMO, and an Tmg internucleotidic linkage.

[0235] In some embodiments, a non-negatively charged internucleotidic linkage has the structure of Formula I, I-a, I-b, I-c, I-n-1, I-n-2, I-n-3, I-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc., or a salt form thereof. In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substituted 3-20 membered heterocyclyl or heteroaryl group having 1-10 heteroatoms. In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substituted 3-20 membered heterocyclyl or heteroaryl group having 1-10 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, such a heterocyclyl or heteroaryl group is of a 5-membered ring. In some embodiments, such a heterocyclyl or heteroaryl group is of a 6-membered ring.

[0236] In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substituted 5-20 membered heteroaryl group having 1-10 heteroatoms. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-20 membered heteroaryl group having 1-10 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-6 membered heteroaryl group having 1-4 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-membered heteroaryl group having 1-4 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, a heteroaryl group is directly bonded to a linkage phosphorus. In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substituted triazolyl group. In some embodiments, a non-negatively charged internucleotidic linkage comprises an unsubstituted triazolyl group, e.g., some embodiments,a non-negatively charged internucleotidic linkage comprises a substituted triazolyl group, e.g., .

[0237] In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substituted 5-20 membered heterocyclyl group having 1-10 heteroatoms. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-20 membered heterocyclyl group having 1-10 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-6 membered heterocyclyl group having 1-4 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, a non- negatively charged internucleotidic linkage comprises an optionally substituted 5-membered heterocyclyl group having 1-4 heteroatoms, wherein at least one heteroatom is nitrogen. In some embodiments, at least two heteroatoms are nitrogen. In some embodiments, a heterocyclyl group is directly bonded to a linkage phosphorus. In some embodiments, a heterocyclyl group is bonded to a linkage phosphorus through a linker, e.g., =N− when the heterocyclyl group is part of a guanidine moiety who directed bonded to a linkage phosphorus through its =N−. In some embodiments, a non-negatively charged internucleotidic linkage comprises an optionally substitutedgroup. In some embodiments, a non-negatively charged internucleotidic linkage comprises an substitutedg oup. In some embodiments, a non-negatively charged internucleotidic linkage comprises agroup, wherein each R1is independently −L−R. In some embodiments, each R1is independently optionally substituted C1-6alkyl. In some embodiments, each R1is independently methyl.

[0238] In some embodiments, a modified internucleotidic linkage, e.g., a non-negatively charged internucleotidic linkage, comprises a triazole or alkyne moiety, each of which is optionally substituted. In some embodiments, a modified internucleotidic linkage comprises a triazole moiety. In some embodiments, a modified internucleotidic linkage comprises a unsubstituted triazole moiety. In some embodiments, a modified internucleotidic linkage comprises a substituted triazole moiety. In some embodiments, a modified internucleotidic linkage comprises an alkyl moiety. In some embodiments, a modified internucleotidic linkage comprises an optionally substituted alkynyl group. In some embodiments, a modified internucleotidic linkage comprises an unsubstituted alkynyl group. In some embodiments, a modified internucleotidic linkage comprises a substituted alkynyl group. In some embodiments, an alkynyl group is directly bonded to a linkage phosphorus.

[0239] In some embodiments, an oligonucleotide comprises different types of internucleotidic phosphorus linkages. In some embodiments, a chirally controlled oligonucleotide comprises at least one natural p...

Claims

1. CLAIMS 1. An oligonucleotide, wherein the oligonucleotide is selected from [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2 r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2 r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), and [fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; [n001] represents [n001R] represents [n001] wherein the phosphorus is of the Rp configuration.

2. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p.[fl2r] (C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ss p].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a salt thereof.

3. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r] (C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ss p].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

4. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p.[fl2r] (C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ss p].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), or a salt thereof.

5. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r] (C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ss p].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a salt thereof.

6. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r] (U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[Ss p].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), or a salt thereof.

7. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p.[fl2r] (C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ss p].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a salt thereof.

8. The oligonucleotide of claim 1, wherein the oligonucleotide is m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p.[fl2r](C) [Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp]. [fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a salt thereof.

9. The oligonucleotide of claim 1, wherein the oligonucleotide is m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](C) [Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[ fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

10. The oligonucleotide of claim 1, wherein the oligonucleotide is m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](U) [Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[ fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a salt thereof.

11. The oligonucleotide of claim 1, wherein the oligonucleotide is m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p.[fl2r](C) [Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp]. [fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

12. The oligonucleotide of claim 1, wherein the oligonucleotide is m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p.[fl2r](C) [Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp]. [fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), or a salt thereof.

13. The oligonucleotide of claim 1, wherein the oligonucleotide is m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](C) [Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[ fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a salt thereof.

14. The oligonucleotide of claim 1, wherein the oligonucleotide is m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](U) [Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[ fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), or a salt thereof.

15. The oligonucleotide of claim 1, wherein the oligonucleotide is m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p.[fl2r](C) [Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp]. [fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a salt thereof.

16. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r] (U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[Ss p].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a salt thereof.

17. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p.[fl2r] (C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ss p].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

18. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p.[fl2r](C )[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp] .[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a salt thereof.

19. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](C) [Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[ fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

20. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[fl2r](U) [Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[ fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a salt thereof.

21. The oligonucleotide of claim 1, wherein the oligonucleotide is [fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p.[fl2r](C) [Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp]. [fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a salt thereof.

22. An oligonucleotide, wherein the oligonucleotide is a compound of formula A or a salt thereof.

23. An oligonucleotide, wherein the oligonucleotide is a compound of formula A-i.

24. An oligonucleotide, wherein the oligonucleotide is a compound of formula B or a salt thereof.

25. An oligonucleotide, wherein the oligonucleotide is a compound of formula B-i.

26. An oligonucleotide, wherein: the base sequence of the oligonucleotide comprises 10 or more contiguous nucleobases of a complement of a DMD transcript; and the oligonucleotide comprises 3 or more PN internucleotidic linkages.

27. An oligonucleotide, wherein: the base sequence of the oligonucleotide comprises 10 or more contiguous nucleobases that are complementary to an equal length portion in a DMD transcript; and the oligonucleotide comprises 3 or more PN internucleotidic linkages.

28. An oligonucleotide, wherein: the oligonucleotide can hybridize to an equal length portion in a DMD transcript; and the oligonucleotide comprises 3 or more PN internucleotidic linkages.

29. An oligonucleotide, wherein the base sequence of the oligonucleotide comprises 15 or more contiguous nucleobases of a complement of a DMD transcript, wherein the oligonucleotide comprises 4 or more PN internucleotidic linkages, and wherein the oligonucleotide comprises a PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside and / or a PN internucleotidic linkage between the 3’ terminal (N) nucleoside and the penultimate (N-1) nucleoside.

30. An oligonucleotide, wherein the base sequence of the oligonucleotide comprises 15 or more contiguous nucleobases of a complement of a DMD transcript, wherein the oligonucleotide comprises a PN internucleotidic linkage between the 5’ terminal (+1) nucleoside and the immediately downstream (+2) nucleoside in the Rp configuration, a PN internucleotidic linkage between the +3 nucleoside and the +4 nucleoside in the Rp configuration, a PN internucleotidic linkage between the +6 nucleoside and the +7 nucleoside in the Rp configuration, and / or a PN internucleotidic linkage between the +17 nucleoside and the +18 nucleoside in the Rp configuration.

31. The oligonucleotide of any one of the preceding claims, wherein each chiral internucleotidic linkage of the oligonucleotide independently has a diastereopurity of at least 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%.

32. The oligonucleotide of any one of the preceding claims, wherein the oligonucleotide is a pharmaceutically acceptable salt, optionally wherein the oligonucleotide is a sodium salt, optionally wherein the number of sodium ions in the sodium salt equals the total number of phosphorothioate internucleotidic linkages and natural phosphate internucleotidic linkages in the oligonucleotide.

33. A chirally controlled oligonucleotide composition comprising an oligonucleotide of any one of the preceding claims, wherein the composition is enriched, relative to a substantially racemic preparation of the oligonucleotide, for the oligonucleotide.

34. A chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides each of which is an oligonucleotide of any one of claims 1-32, wherein oligonucleotides of the plurality share the same constitution and at least 5% of all oligonucleotides in the composition that share the same constitution are oligonucleotides of the plurality.

35. A chirally controlled oligonucleotide composition comprising an oligonucleotide of any one of claims 1-32, wherein at least 5% of all oligonucleotides in the composition that share the same constitution as the oligonucleotide are the oligonucleotide.

36. The composition of any one of claims 34-35, wherein at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of all oligonucleotides in the composition that share the same constitution are oligonucleotides of the plurality; or wherein at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of all oligonucleotides in the composition that share the same base sequence are oligonucleotides of the plurality.

37. An oligonucleotide composition comprising a plurality of oligonucleotides, wherein oligonucleotides of the plurality share: 1) a common base sequence; and 2) the same linkage phosphorus stereochemistry independently at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more chiral internucleotidic linkages; wherein oligonucleotides of the plurality are an oligonucleotide of any one of claims 1-32; and wherein at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the oligonucleotides in the composition that share the common base sequence are oligonucleotides of the plurality.

38. The oligonucleotide composition of claim 37, wherein oligonucleotides of the plurality share the same linkage phosphorus stereochemistry independently at each chiral internucleotidic linkage.

39. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of:[fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

40. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

41. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m( A)p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[f l2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and[n001R] representswherein the phosphorus is of the Rp configuration.

42. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2 r](C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

43. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

44. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

45. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

46. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and[n001R] representswherein the phosphorus is of the Rp configuration.

47. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

48. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

49. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(G)[n001R].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

50. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(C)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

51. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p.[ fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and[n001R] representswherein the phosphorus is of the Rp configuration.

52. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: m(A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].m(G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

53. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](U)[n001R].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A )p.[fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2 r](U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

54. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](A)[n001R].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U )p.[fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

55. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(A)[Ssp].[fl2r](C)[Ssp].m(A)p.m(G)[Ssp].[fl2r](U)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

56. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](A)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](C)[Ssp].[fl2r](A)[Ssp].m(G)[Ssp].[fl2r](U)[Ssp].m(U)p.m(U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[Ssp].[fl2r]( C)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and[n001R] representswherein the phosphorus is of the Rp configuration.

57. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](U)[Ssp].[fl2r](G)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(A)p. [fl2r](U)[Ssp].[fl2r](G)[Ssp].m(C)[Ssp].[fl2r](C)[Ssp].m(A)p.m(U)[Ssp].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r]( U)[Ssp].[fl2r](G)[n001R].[fl2r](G)[Ssp].[fl2r](A)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

58. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are oligonucleotides each independently having the structure of: [fl2r](A)[Ssp].[fl2r](U)[Ssp].[fl2r](G)[n001R].[fl2r](C)[Ssp].[fl2r](C)[Ssp].[fl2r](A)[n001R].m(U)p. [fl2r](C)[Ssp].[fl2r](C)[Ssp].m(U)[Ssp].[fl2r](G)[Ssp].m(G)p.m(A)[Ssp].[fl2r](G)[Ssp].[fl2r](U)[Ssp].[fl2r]( U)[Ssp].[fl2r](C)[n001R].[fl2r](C)[Ssp].[fl2r](U)[Ssp].[fl2r](G), or a pharmaceutically acceptable salt thereof, wherein: [fl2r] represents a 2’-F modified nucleoside; m represents a 2’-OMe modified nucleoside; p represents a phosphodiester; [Ssp] represents a phosphorothioate in the Sp configuration; and [n001R] representswherein the phosphorus is of the Rp configuration.

59. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are each independently a compound of formula A or pharmaceutically acceptable salt thereof.

60. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are each independently a compound of formula A-i.

61. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are each independently a compound of formula B or pharmaceutically acceptable salt thereof.

62. An oligonucleotide composition, wherein a level of all oligonucleotides in the composition are each independently a compound of formula B-i.

63. The composition of any one of claims 39-62, wherein a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of all oligonucleotides that share the same base sequence as an oligonucleotide having the structure or a pharmaceutically acceptable salt thereof; or wherein a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of all oligonucleotides that share the same constitution as an oligonucleotide having the structure or a pharmaceutically acceptable salt thereof; or wherein a level is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more based on UV peak area at 260 nm.

64. The composition of any one of claims 33-62, wherein a level or percentage is about or at least about (DS)nc, wherein DS is about or at least about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, and nc is the number of chirally controlled internucleotidic linkages (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more); or wherein the level or percentage is about or at least about (DS)nc, wherein DS is about or at least about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, and nc is the number of chiral linkage phosphorus in an oligonucleotide of the plurality (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more).

65. A pharmaceutical composition, comprising an oligonucleotide or oligonucleotide composition of any one of the preceding claims, and a pharmaceutically acceptable carrier.

66. The pharmaceutical composition of claim 65, wherein the pharmaceutical composition comprises one or more pharmaceutically acceptable salts of an oligonucleotide and / or the pharmaceutical composition is a solution.

67. A method for altering splicing of a DMD transcript in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

68. A method for providing DMD exon skipping in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

69. A method for increasing level of a DMD polypeptide in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

70. The method of claim 69, wherein the DMD polypeptide is a truncated dystrophin.

71. A method for increasing level of dystrophin in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

72. A method for increasing level of a dystrophin polypeptide encoded by exon 45-skipped DMD transcript in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

73. A method for increasing level of DMD activity in a system, comprising administering or delivering to the system an effective amount of an oligonucleotide or composition of any one of the preceding claims.

74. The method of any one of claims 67-73, wherein the system expresses DMD transcripts and / or the system comprises a mutation of the DMD gene, optionally wherein the mutation is amenable to exon 45 skipping.

75. The method of any one of claims 67-74, wherein the system comprises or is a cell, tissue, organ, animal, human or subject, optionally wherein the cell comprises or is a skeletal muscle cell, a cardiac muscle cell, or a neuron; the tissue comprises or is a muscle tissue; and / or the animal comprises a mouse or a non-human primate.

76. A method for treating muscular dystrophy, comprising administering or delivering to a subject suffering therefrom an effective amount of an oligonucleotide or composition of any one of the preceding claims.

77. The method of any one of claims 75-76, wherein the subject is suffering from Duchenne’s muscular dystrophy or Becker’s muscular dystrophy and / or the subject has a mutation of the DMD gene that is amenable to exon 45 skipping.

78. The oligonucleotide, composition or method of any one of the preceding claims, wherein the mutation of the DMD gene is Δ7-44, Δ12-44, Δ18-44, Δ44, Δ46, Δ46-47, Δ46-48, Δ46-49, Δ46-51, Δ46-53, Δ46-55, Δ46-57, Δ46-59, Δ46-60, Δ46-67, Δ46-69, Δ46-75, or Δ46-78; optionally wherein the mutation comprises Δ44 or Δ46.

79. The method of any one of the preceding claims, wherein exon 45 is skipped in DMD mRNA.

80. The method of any one of the preceding claims, wherein level of exon 45-skipped DMD mRNA is increased as compared to absence of the oligonucleotide or composition and / or as compared to administering or delivering a reference oligonucleotide or composition.

81. The method of any one of the preceding claims, wherein a truncated DMD polypeptide is produced as compared to a wild-type DMD protein, optionally wherein the truncated DMD polypeptide performs one or more functions of wild-type dystrophin.

82. The method of any one of the preceding claims, wherein level of a truncated DMD polypeptide is increased as compared to absence of the oligonucleotide or composition and / or as compared to administering or delivering a reference oligonucleotide or composition.

83. The method of claim 80 or 82, wherein the reference oligonucleotide targets DMD or the reference composition comprises oligonucleotides targeting DMD.

84. An oligonucleotide or composition of any one of the preceding claims, for use in a method of any one of the preceding claims.

85. An oligonucleotide or composition of any one of the preceding claims, for use in manufacturing a medicament for a method of any one of the preceding claims.

86. Use of an oligonucleotide or composition of any one of the preceding claims in a method of any one of the preceding claims.

87. Use of an oligonucleotide or composition of any one of the preceding claims in manufacturing a medicament for a method of any one of the preceding claims.

88. A method for manufacturing an oligonucleotide or composition of any one of the preceding claims according to a method described in the specification.

89. An oligonucleotide, composition, method, or use of any one of Embodiments 1-369.

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