Polynucleotide compositions and methods for regulating gene expression

Abstract

The present disclosure relates to engineered polynucleotides that interact with pre-mRNA and spliceosomes to regulate gene expression. The engineered polynucleotides have stem-loop structures that recruit spliceosomes and targeting sequences that are complementary to target sequences at exon-intron splice sites, and can include nucleotides with 2' modifications and phosphorothioate bonds.

Description

[Technical field]

[0001] cross reference This application claims the benefit of U.S. Provisional Application No. 63 / 222,741, filed July 16, 2021, which is incorporated by reference in its entirety for all purposes. [Background technology]

[0002] Gene editing using clustered regularly interspaced short palindromic repeats (CRISPR) technology may result in permanent deoxyribonucleic acid (DNA) mutations, thus presenting off-target challenges, for example, in therapeutic applications. The efficiency of gene regulation at the ribonucleic acid (RNA) level remains limited. Therefore, there is a need to develop polynucleotide compositions and methods for regulating gene expression and activity at therapeutically effective and safe levels, for example. Summary of the Invention

[0003] Described herein, in some aspects, is an engineered polynucleotide, the engineered polynucleotide comprising one or more targeting moieties configured to bind to a pre-messenger ribonucleic acid (pre-mRNA) at a target sequence therein, and a recruitment moiety configured to recruit a post-transcriptional regulatory moiety (e.g., a spliceosome moiety), such that when associated with the pre-mRNA and the engineered polynucleotide, the post-transcriptional regulatory moiety modifies the pre-mRNA at or adjacent to the target sequence. In some embodiments, the targeting moiety of the one or more targeting moieties is sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene. In some embodiments, the one or more targeting moieties comprise a first targeting moiety configured to specifically bind to a first target sequence in the target sequence of the pre-mRNA, and a second targeting moiety configured to specifically bind to a second target sequence in the target sequence of the pre-mRNA. In some embodiments, the first target sequence comprises a consensus sequence in the target sequence. In some embodiments, the second target sequence comprises a consensus sequence in the target sequence. In some embodiments, the first target sequence and the second target sequence are separated in the target sequence by a spacing sequence of 5 nucleotides or less (e.g., 1 or 2 nucleotides). In some embodiments, the target sequence comprises an exon-intron boundary in the pre-mRNA. In some embodiments, the first target sequence and the second target sequence are both 5' or 3' to the exon-intron boundary. In some embodiments, one of the first target sequence and the second target sequence is 5' to the exon-intron boundary, and the other of the first target sequence and the second target sequence is 3' to the exon-intron boundary. In some embodiments, the target sequence comprises a splice site in the pre-mRNA. In some embodiments, the first target sequence or the second target sequence comprises a splice site (e.g., 5'ss) in the pre-mRNA.In some embodiments, one of the first and second targeting moieties is 5' to the recruitment moiety, and the other of the first and second targeting moieties is 3' to the recruitment moiety. In some embodiments, the first targeting moiety or the second targeting moiety comprises a sequence identical to or complementary to a sequence listed in Table 1. In some embodiments, the first targeting moiety comprises a sequence identical to or complementary to a sequence selected from the 5'-targeting moiety sequence column of Table 1, and the second targeting moiety comprises a sequence identical to or complementary to a sequence listed in the 3'-targeting moiety sequence column of Table 1. In some embodiments, the first targeting moiety comprises a sequence identical to or complementary to a sequence listed in the 3'-targeting moiety sequence column of Table 1, and the second targeting moiety comprises a sequence identical to or complementary to a sequence listed in the 5'-targeting moiety sequence column of Table 1. In some embodiments, the first targeting moiety or the second targeting moiety comprises a sequence identical to or complementary to a consensus sequence of an intron donor site (e.g., selected from GU, GT, GC, and CA). In some embodiments, the first targeting moiety or the second targeting moiety comprises a sequence identical to or complementary to a consensus sequence of an exon donor site (e.g., G). In some embodiments, the first targeting moiety or the second targeting moiety comprises a sequence identical to or complementary to a consensus sequence selected from GU, GT, GC, G, and CA. In some embodiments, the spliceosome moiety is selected from a spliceosomal ribonucleoprotein complex, a spliceosomal small nuclear ribonucleic acid (snRNA), a spliceosomal protein, a functional variant thereof, or a functional fragment thereof. In some embodiments, the spliceosomal moiety comprises U1 snRNA and a spliceosomal protein. In some embodiments, the spliceosomal snRNA is selected from U1, U2, U4, U5, U6, U11, U12, U14atac, U6atac, and combinations thereof. In some embodiments, the spliceosomal protein is selected from Sm, U1-70k, U1A, U1C, and combinations thereof.In some embodiments, the recruitment portion comprises a nucleotide sequence that is at least 70%, 80%, 85%, or 90% identical to or complementary to a sequence set forth in Tables 2-3. In some embodiments, the recruitment portion comprises a nucleotide sequence that is identical to or complementary to a sequence set forth in Tables 2-3. In some embodiments, the engineered polynucleotide comprises a (e.g., secondary) structural feature. In some embodiments, the engineered polynucleotide comprises an apical loop, an upper stem, an internal loop, a lower stem, or a combination thereof. In some embodiments, the engineered polynucleotide comprises a loop (e.g., an internal loop) adjacent to a stem (e.g., a lower stem, or an upper stem) that comprises two complementary stem sequences. In some embodiments, the stem sequence of the stem (e.g., the lower stem, or the upper stem) comprises about 5, 4, or 3 nucleotides or less. In some embodiments, the loop is an internal loop adjacent to the stem (e.g., the lower stem) and an additional stem (e.g., an upper stem) that comprises two complementary stem sequences. In some embodiments, the internal loop comprises a nucleic acid sequence of 10, 9, or 8 nucleotides or less. In some embodiments, the stem sequence of the additional stem (e.g., the upper stem) comprises about 5, 4, or 3 nucleotides or less. In some embodiments, the engineered polynucleotide further comprises an apical loop. In some embodiments, the apical loop comprises a nucleic acid sequence of 10, 9, 8, 7, 6, or 5 nucleotides or less. In some embodiments, the engineered polynucleotide does not comprise any intramolecular disulfide bonds. In some embodiments, the engineered polynucleotide, when associated with the spliceosome portion, the pre-mRNA exhibits substantially no base pairing with the RNA binding domain (RBD) of U1 snRNA. In some embodiments, the engineered polynucleotide, when associated with the spliceosome portion, the pre-mRNA exhibits substantially no base-specific interaction with U1-C protein. In some embodiments, the engineered polynucleotide is configured to specifically interact with the zinc fingers of U1-C protein in particular.In some embodiments, the 5'-targeting portion of the engineered polynucleotide is configured to specifically interact with a zinc finger of the U1-C protein. In some embodiments, the engineered polynucleotide is configured to covalently interact with a zinc finger of the U1-C protein (e.g., via a disulfide bond). In some embodiments, the engineered polynucleotide is configured to non-covalently interact with a zinc finger of the Ul-C protein (e.g., via a hydrogen bond). In some embodiments, the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, one side of the stem loop structure of the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, the subsequence comprises a sequence corresponding to 5'-GGCCU-3' of SL2 of U1 snRNA. In some embodiments, the subsequence does not comprise a sequence corresponding to 5'-CACGUUA-3' of SL2 of U1 snRNA. In some embodiments, the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the internal loop of the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the lower stem of the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the anchor sequence comprises a sequence corresponding to 5'-CACGUUA-3'. In some embodiments, the engineered polynucleotide exhibits substantially no base pairing with the H-helix of U1 snRNA. In some embodiments, the engineered polynucleotide comprises at least one chemical modification. In some embodiments, the engineered polynucleotide comprises at least one 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotide.In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are chemically modified nucleotides. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotides. In some embodiments, the polynucleotide comprises at least one phosphorothioate internucleotide linkage. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages of the engineered polynucleotide are chemically modified. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages are phosphorothioate. In some embodiments, the engineered polynucleotide comprises about 10 to about 40 nucleotides, about 10 to about 35 nucleotides, about 10 to about 30 nucleotides, or about 10 to about 25 nucleotides. In some embodiments, the recruitment moiety comprises about 10 to about 30 nucleotides, or about 10 to about 20 nucleotides. In some embodiments, the one or more targeting moieties each independently comprise about 2 to about 15 nucleotides, about 2 nucleotides to about 10 nucleotides, or about 2 nucleotides to about 8 nucleotides. In some embodiments, one of the first targeting moiety and the second targeting moiety comprises about 2 nucleotides, and the other of the first targeting moiety and the second targeting moiety comprises 5 or 6 nucleotides. In some embodiments, when associated with the engineered polynucleotide and the pre-mRNA, the spliceosome moiety cleaves or splices the pre-mRNA in the target sequence. In some embodiments, the spliceosome moiety further promotes modification of the cleaved pre-mRNA.

[0004] Described herein, in some aspects, are engineered polynucleotides, the engineered polynucleotides comprising a nucleotide sequence at least 70%, 80%, 85%, or 90% identical to or complementary to a sequence set forth in Tables 2-3, the engineered polynucleotides being characterized by (e.g., secondary) structural features. In some embodiments, the nucleotide sequence is identical to or complementary to a sequence set forth in Tables 2-3. In some embodiments, the structural features comprise one or more stem-loop structures. In some embodiments, the structural features comprise an apical loop, an upper stem, an internal loop, a lower stem, or a combination thereof. In some embodiments, the engineered polynucleotide comprises a loop (e.g., an internal loop) adjacent to a stem (e.g., a lower stem, or an upper stem) comprising two complementary stem sequences. In some embodiments, the stem sequence of the stem (e.g., the lower stem, or the upper stem) comprises no more than about 5, 4, or 3 nucleotides. In some embodiments, the loop is an internal loop flanked by the stem (e.g., the lower stem) and an additional stem (e.g., the upper stem) that comprises two complementary stem sequences. In some embodiments, the internal loop comprises a nucleic acid sequence of 10, 9, or 8 nucleotides or less. In some embodiments, the stem sequence of the additional stem (e.g., the upper stem) comprises about 5, 4, or 3 nucleotides or less. In some embodiments, the engineered polynucleotide further comprises an apical loop. In some embodiments, the apical loop comprises a nucleic acid sequence of 10, 9, 8, 7, 6, or 5 nucleotides or less. In some embodiments, the engineered polynucleotide further comprises one or more targeting moieties that are sufficiently identical to or complementary to a target sequence of a target gene. In some embodiments, the targeting moieties of the one or more targeting moieties are sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene. In some embodiments, the target gene is microtubule-associated protein tau (MAPT). In some embodiments, the engineered polynucleotide comprises at least one chemical modification.In some embodiments, the engineered polynucleotide comprises at least one phosphorothioate internucleotide linkage. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages of the engineered polynucleotide are chemically modified. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages are phosphorothioate. In some embodiments, the engineered polynucleotide comprises at least one 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotide. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are chemically modified nucleotides. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotides. In some embodiments, the engineered polynucleotide comprises from about 10 to about 40 nucleotides, from about 10 to about 35 nucleotides, from about 10 to about 30 nucleotides, or from about 10 to about 25 nucleotides.

[0005] Described herein, in some aspects, is a method of modifying a pre-messenger ribonucleic acid (pre-mRNA) in a cell, comprising contacting the cell with an engineered polynucleotide comprising one or more targeting moieties and a recruitment moiety, wherein the one or more targeting moieties bind to the pre-mRNA at a target sequence therein, and the recruitment moiety recruits a post-transcriptional regulatory moiety (e.g., a spliceosomal moiety) within the vicinity of the target sequence of the pre-mRNA to modify the pre-mRNA in the cell, thereby resulting in one or more modified pre-mRNAs. In some embodiments, the targeting moiety of the one or more targeting moieties is sufficiently identical to or complementary to a consensus sequence in the target sequence of a target gene. In some embodiments, the pre-mRNA corresponds to a target gene. In some embodiments, the target gene is microtubule-associated protein tau (MAPT). In some embodiments, the method modifies the expression or activity of the target gene. In some embodiments, prior to the contacting step, the cell exhibits an abnormal messenger ribonucleic acid (mRNA) or protein corresponding to the target gene.

[0006] Described herein, in some embodiments, are sets of engineered polynucleotides, each of which independently comprises one or more targeting moieties configured to bind to a pre-messenger ribonucleic acid (pre-mRNA) at a target sequence, and a recruitment moiety configured to recruit a post-transcriptional regulatory moiety (e.g., a spliceosome moiety), and is configured to specifically bind to the pre-mRNA at a plurality of target sequences, including the target sequence.

[0007] Another embodiment described herein is an engineered polynucleotide, the engineered polynucleotide comprising a first targeting portion configured to specifically bind to a pre-messenger ribonucleic acid (pre-mRNA) at a first target sequence therein, a recruitment portion configured to recruit a spliceosome portion, and a second targeting portion configured to specifically bind to a pre-mRNA at a second target sequence therein; The recruitment portion comprises an apical loop, an upper stem adjacent to the apical loop, a lower stem, and an internal loop located between the upper and lower stems, and the spliceosome portion, when associated with the pre-mRNA and the engineered polynucleotide, modifies the pre-mRNA at a target sequence comprising the first target sequence and the second target sequence. In some embodiments, the first target sequence and the second target sequence are separated in the target sequence by a spacing sequence of 5 nucleotides or less. In some embodiments, the target sequence comprises an exon-intron boundary in the pre-mRNA. In some embodiments, the first target sequence is 5' of the exon-intron boundary and the second target sequence is 3' of the exon-intron boundary. In some embodiments, the first targeting portion comprises a sequence identical or complementary to a sequence listed in the exon sequence column of Table 1, and the second targeting portion comprises a sequence identical or complementary to a sequence listed in the exon sequence column of Table 1. In some embodiments, the spliceosome portion comprises U1 snRNA and U1-C protein. In some embodiments, the upper stem or the lower stem comprises two complementary sequences, each of the two complementary sequences comprises 5 nucleotides or less, the internal loop comprises two nucleic acid sequences, each of the two nucleic acid sequences comprises 5 nucleotides or less, and the apical loop comprises a nucleic acid sequence of 8 nucleotides or less. In another embodiment, the pre-mRNA, when associated with the engineered polynucleotide, does not substantially exhibit base pairing with the RNA binding domain (RBD) of U1 snRNA, and the spliceosome portion, when associated with the engineered polynucleotide and the spliceosome portion, does not substantially exhibit base-specific interaction with U1-C protein. In other embodiments, the 5'-targeting portion of the engineered polynucleotide is configured to specifically interact with the zinc finger of U1-C protein. In other embodiments, the recruitment portion comprises a nucleotide sequence complementary to at least 4 nucleotides of the sequence of stem loop II (SL2) of U1 snRNA. In other embodiments, the sequence of SL2 of U1 snRNA comprises 5'-GGCCU-3'. The engineered polynucleotide may have 2'-modified nucleotides.At least 50% of the nucleotides of the engineered polynucleotide can be 2'-modified nucleotides. The 2'-modified nucleotides can be 2'-methoxy nucleotides. In other embodiments, the engineered polynucleotide comprises nucleotides connected by internucleotide linkages, at least one of the internucleotide linkages does not contain a phosphate. At least one, or 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages can be phosphorothioates.

[0008] INCORPORATION BY REFERENCE All publications, patents, and patent applications mentioned in this specification are incorporated by reference herein to the same extent as if each individual publication, patent, or patent application was specifically and individually incorporated by reference herein. To the extent that the publications and patents or patent applications incorporated by reference conflict with the disclosure contained herein, the specification is intended to supersede and / or take precedence over such conflicting material. [Brief description of the drawings]

[0009] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application file with a color drawing will be provided by the Office upon request and payment of the necessary fee. [Figure 1]Illustrates a schematic diagram for the identification of splice donor and splice acceptor sites. An exemplary consensus sequence for messenger ribonucleic acid (mRNA) splicing in animals and plants is "GU_AG", where "GU" is an exemplary splice donor sequence, and "AG" is an exemplary splice acceptor sequence. A longer splice donor consensus sequence in mammals can be "GUrAGU", where "r" represents either "G" or "A". Usually, the expression "GU_AG" means that only the two nucleotides at the 5' and 3' ends of the sequence are invariant as "GU" and "AG", respectively, and the sequence represented by the underline can be any sequence. However, the present expression described herein indicates that the sequence represented by the underline can be any sequence except for sequences that do not match any of the other consensus sequences. The splice acceptor consensus sequence is preceded by a branch point sequence, which contains an adenine that is linked to the 5' splice site ribonucleotide to form the intron lariat, and a polypyrimidine tract (C or U) between the branch point and the splice acceptor sequence. It is clear that the short GU_AG consensus sequence of the intron is not sufficient to distinguish among the numerous alternative splicing events, but surprisingly little is known about other sequence information required to regulate alternative RNA splicing. One or two nucleotides flanking both sides of the intron are also often conserved, and although they are included in our supplementary table, they will not be discussed further here, allowing us to focus our analysis of the consensus sequences at the ends of the introns. In this sense, the rational design of the engineered polynucleotides logically identifies the intron consensus sequence (GU_AG) of the splice. It is then possible to determine the conserved regions of the donor site (5' exon and intron downstream) and the acceptor (3' exon and intron downstream). It is important to note that the conserved and consensus regions are located within the same site of the constitutive splice donor or acceptor.The recognition of consensus regions determines the 5' splice sites that are the limits of the junctions between exons and introns, whereas the recognition of conserved regions identifies the identity of the transcripts that are selected for regulation. [Figure 2A] Illustrated are exemplary engineered polynucleotides described herein, which include: (1) 3'-targeting portion: 3'-GC-5', (2) lower stem: 3'-GA-5' / 5'-CT3', (3) internal loop: 3'-CC-5' / 5'-AA-3', (4) upper stem: 3'-GGA-5' / 5'-CCT-3', (5) apical loop: 3'-CTT-5', and (6) 5'-targeting portion: 5'-GTCCA-3'. [Figure 2B] Illustrated are exemplary engineered polynucleotides described herein, which include: (1) 3'-targeting portion: 3'-GC-5', (2) lower stem: 3'-GA-5' / 5'-CT3', (3) internal loop: 3'-CC-5' / 5'-AA-3', (4) upper stem: 3'-GGA-5' / 5'-CCT-3', (5) apical loop: 3'-CTT-5', and (6) 5'-targeting portion: 5'-GTCCA-3'. [Figure 2C] 1 illustrates the interaction of an exemplary engineered polynucleotide with a target pre-mRNA sequence. [Figure 2D] 1 illustrates the interaction of an exemplary engineered polynucleotide with various components of the U1 RNP complex. [Figure 3A] FIG. 3A illustrates an anchor that occurs via an engineered polynucleotide "stem 5' / 3'" (aka 5'-targeting moiety, or / and 3'-targeting moiety) designed to interact with a conserved portion present in the constitutive donor site. Stem 5' / 3' (GTCCA and CG) phosphorothioate internucleotide linkages to the molecular sugar and substitutions such as 2'O-methyl (2'O-ME) increase resistance to endonucleases and increase the molecular strength of the interaction between the bases of the stem 5' / 3' and the conserved region from the constitutive donor. [Figure 3B]3A illustrates anchoring that occurs via an engineered polynucleotide "stem 5' / 3'" (aka 5'-targeting portion, or / and 3'-targeting portion) designed to interact with a conserved portion present in a constitutive donor site. FIG. 3B. Interaction of the engineered polynucleotides described herein with constitutive donor splicing and silencing of the RNA binding portion (RBD) of U1 snRNA by the constitutive donor splicing-exon. [Figure 4] A diagram of the human U1 snRNP is illustrated. The U1 snRNP consists of one U1 snRNA, seven common Sm proteins and three U1 snRNP-specific proteins (U1-70K, U1A and U1C). The secondary structure of the U1 snRNA consists of four stem-loops (SL) and a highlighted H-helix. The nucleotides forming the H-helix are indicated. Additionally, the U1 snRNA sequence relevant for RNA:protein or RNA:5' splice site interactions are indicated as well. The loop portion of SL1 is drawn according to the crystal structure. It is closed by a trans WC / Hoogsteen base pair formed between A29 and A36. The protein components of the U1 snRNP, their sizes and their approximate positions are indicated as well. The Sm ring formed by the Sm proteins is indicated by a green circle that binds to the boxed Sm site. U1-70K, indicated in red, recognizes SL1. U1A, indicated in yellow, binds to SL2. U1C, shown in blue, is recruited to the U1 snRNP by protein:protein interactions with U1-70 K and Sm proteins. Note indicates the interaction between U1C and the Sm ring. [Figure 5A]We illustrate that U1 snRNP binds to the 5' exon-intron junction of pre-mRNA and thus plays a key role in the early steps of pre-mRNA splicing. Two crystal structures of engineered U1 substructures are presented, which together reveal at atomic resolution a near-complete network of protein-protein and RNA-protein interactions within U1 snRNP and show how the 5' splice site of pre-mRNA is recognized by U1 snRNP. The zinc fingers of U1-C interact with the duplex between the pre-mRNA and the 5'-end of U1 snRNA. The binding of the RNA duplex is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the RNA backbone around the splice junction, whereas U1-C does not make base-specific contacts with the pre-mRNA. Our structure and RNA-binding assays indicate that 5'-splice site nucleotide selection by U1 snRNP is achieved primarily through base pairing with U1 snRNA, while U1-C fine-tunes the relative affinity of mismatched 5'-splice sites. Figure 5A. U1-70k in complex with the U1 snRNA stem-loop, and U1-A RRM in complex with stem-loop 2. [Figure 5B]We show that U1 snRNP binds to the 5' exon-intron junction of pre-mRNA and thus plays a key role in the early steps of pre-mRNA splicing. Two crystal structures of engineered U1 substructures are presented, which together reveal at atomic resolution a nearly complete network of protein-protein and RNA-protein interactions within U1 snRNP and show how the 5' splice site of pre-mRNA is recognized by U1 snRNP. The zinc fingers of U1-C interact with the duplex between the pre-mRNA and the 5'-end of U1 snRNA. The binding of the RNA duplex is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the RNA backbone around the splice junction, whereas U1-C does not make base-specific contacts with the pre-mRNA. The structure and RNA-binding assays show that nucleotide selection of the 5' splice site by U1 snRNP is achieved primarily by base pairing with U1 snRNA, while U1-C fine-tunes the relative affinity of mismatched 5' splice sites. Figure 5B. U1 snRNA stem-loops 1 and 2 (55-MER). [Figure 5C]We show that U1 snRNP binds to the 5' exon-intron junction of pre-mRNA and thus plays a key role in the early steps of pre-mRNA splicing. Two crystal structures of engineered U1 substructures are presented, which together reveal at atomic resolution a nearly complete network of protein-protein and RNA-protein interactions within U1 snRNP and show how the 5' splice site of pre-mRNA is recognized by U1 snRNP. The zinc fingers of U1-C interact with the duplex between the pre-mRNA and the 5'-end of U1 snRNA. The binding of the RNA duplex is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the RNA backbone around the splice junction, whereas U1-C does not make base-specific contacts with the pre-mRNA. The structure and RNA-binding assays show that nucleotide selection of the 5' splice site by U1 snRNP is achieved primarily by base pairing with U1 snRNA, while U1-C fine-tunes the relative affinity of mismatched 5' splice sites. FIG. 5C. U1 small nuclear ribonucleoprotein A and 70 kDa. [Figure 6] Illustrated is U1-70k in complex with the U1 snRNA stem loop and U1-A RRM in complex with stem loop 2, stabilized via the U1-C zinc finger. [Figure 7]1 illustrates a schematic of the regulation of the spliceosome machinery by the engineered polynucleotide (ASMO1) described herein. The anchor of the targeting moiety ("stem 5' / 3'") (5'-GTCCA-3' and 5'-CG-3') allows interaction with a conserved site of the constitutive donor by silencing the RNA-binding portion (RBD) of U1 snRNA. Stabilization of the U1 snRNP complex can be observed by the strong ionic attraction of the zinc finger of U1-C induced by disulfide bridge with the thiol of ASMO1 stem 5' / 3'. The pre-mRNA / ASMO1 duplex binding is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the pre-mRNA backbone around the seam, but U1-C does not make base-specific contacts with the pre-mRNA. The structure demonstrates that the selection of the nucleotide for 5'-splicing by U1 snRNP is achieved primarily by interactions between stem 5' / 3' and the pre-mRNA. On the other hand, U1-C regulates the relative affinity of the 5'-splice mismatch site and stabilizes the core of the spliceosomal machinery by bridging the interaction between U1-70KDa and the Sm ring. Electrostatic interactions of stem-loop II with specific bases (5'-AGGCC-3') in the upper stem (also known as "hairpin-2'; see Figure 2B) (3'-GGA-5' / 5'-CCT-3') and the internal loop: (3'-mCC-5' / 5'-AA-3'), as well as hydrogen bridges can be observed in association with the regulation of the polyadenylation signal and acetylation by U1-A. Note that the anchor part of U1-A in stem-loop II (5'-CAACGUUA-3') is not silenced by the upper stem, inducing regulation of the levels of gene expression and acetylation. Furthermore, the presence of the 2'-OME group induces changes in the molecular dynamics of the medium, promoting the conformational change of U1-snRNA and the approximation of stem-loop II to ASMO1, and the ASMO1 targeting or recruiting part, unlike the U1-A protein, reduces the possibility of premature interruption of the reading frame due to deregulation of the polyadenylation signal. [Figure 8]Shown is U1-70k in complex with U1 snRNA stem-loop and U1-A RRM in complex with stem-loop 2, stabilized via U1-C zinc finger. Electrostatic interactions and hydrogen bridges of stem-loop II with specific bases (3'-CCGGA-5') of the upper stem (3'-GGA-5' / 5'-CCT-3') and internal loop: (3'-mCC-5' / 5'-AA-3'); can be observed in association with the regulation of polyadenylation signal and acetylation by U1-A. Note that the anchor part of U1-A in stem-loop II (5'-CAACGUUA-3') is not silenced by the upper stem, inducing regulation of the levels of gene expression and acetylation. Furthermore, the presence of the 2'-OME group induces changes in the molecular dynamics of the medium, promoting conformational changes of U1-SnRNA and the approximation of stem-loop II to the engineered polynucleotide described herein (ASMO1). [Figure 9A] 1 illustrates that U1-C is located on SmD3 and its binding can be stabilized by the N-terminus of U1-70k. [Figure 9B] It illustrates that U1-C forms hydrogen bonds with the sugar-phosphate backbone atoms but does not contact the RNA bases. On the 5'SS strand, nucleotides are colored teal for exon sequences and light tan for intron sequences. [Figure 9C] 9 illustrates a schematic diagram of 5'-splice site recognition. Red dotted line: hydrogen bonds made by amino acid side chains of the U1-C zinc finger. Blue dotted line: hydrogen bonds made by main chain atoms of the U1-C zinc finger. Green dotted line: disulfide bonds made by amino acid side chains of the U1-C zinc finger. Orange dotted line: disulfide bonds made by main chain atoms of the U1-C zinc finger. The 5'SS nucleotide is encoded by the nucleus as in Figure 9B. [Figure 10A] Fingerprint Z1 U1-C snRNP represented by 36 amino acid residues in blue is shown. [Figure 10B]The Z1 finger portion of the U1-C snRNP is shown, highlighting the key residues in the 5′ constitutive donor region that interact with the pre-mRNA / ASMO1 duplex. [Figure 10C] A representative sequence of the U1-C snRNP containing 145-aa is illustrated, with the 36-aa highlighted in green indicating the zinc finger portion. [Figure 11] Exemplary engineered polynucleotides (ASMO2) are illustrated that include modified antisense regulatory oligonucleotides with phosphorothioate internucleotide linkages and 2'-methyl (2'O-ME) substitutions for the sugar moieties. The ASMO2 engineered polynucleotides can be complementary to and can bind to U1 snRNA for regulation of expression and activity of a target sequence encoding a target gene.

[0010] The novel features of the present disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure can be obtained by reference to the following detailed description that sets forth illustrative embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Described herein are (e.g., engineered) polynucleotides and (e.g., pharmaceutical) compositions and methods that utilize them, e.g., for modulating gene expression or activity.

[0012] Engineered Polynucleotides In some embodiments described herein, an engineered polynucleotide comprises (i) one or more targeting moieties configured to bind (e.g., specifically) a ribonucleic acid (RNA) (e.g., a messenger ribonucleic acid (mRNA) such as a pre-messenger ribonucleic acid (pre-mRNA)) at a target sequence therein. The engineered polynucleotide may further comprise (ii) a recruitment moiety configured to recruit a post-transcriptional regulatory moiety (e.g., a spliceosome moiety) such that, when associated with an RNA (e.g., an mRNA such as a pre-mRNA) and the engineered polynucleotide, the post-transcriptional regulatory moiety modifies the RNA (e.g., an mRNA such as a pre-mRNA) in or adjacent to the target sequence. In some embodiments, the RNA (e.g., an mRNA such as a pre-mRNA) encodes a target gene.

[0013] An engineered polynucleotide, or an engineered polynucleotide as described herein, may include various moieties. A "moiety" may refer to a region of an engineered polynucleotide. In some cases, a moiety may be described in terms of the function of the moiety. For example, a "targeting moiety" may refer to a region of an engineered polynucleotide that may be at least partially complementary to a target RNA, a "recruitment moiety" may refer to a moiety that may recruit any one of the regulatory moieties described herein, and a "spacing sequence" may refer to a moiety that provides spacing between other moieties. In some instances, the listing of a moiety name does not limit the moiety to a particular function. For example, a "targeting moiety" that may be at least partially complementary to a target RNA may in some instances recruit a regulatory moiety.

[0014] targeting part In some embodiments of the engineered polynucleotide described herein, the targeting moiety of one or more targeting moieties is sufficiently identical or complementary to the consensus sequence in the target sequence of the target gene.Targeting moieties can be found at the 5' and 3' ends of the engineered polynucleotide, also known as the lower stem or foot.Without wishing to be bound by theory, one or two targeting moieties stably bind to the constitutive donor 5' of the target pre-mRNA, allowing interaction with the conserved site of the constitutive donor to silence the U1 snRNA RNA binding domain.

[0015] Consensus sequences can be determined based on the identification of genetic variants of unknown significance (VUS). Any exonic or intronic VUS can be splice-forming by disrupting cis-DNA sequences that define exons, introns and regulatory sequences required for the correct RNA splicing process. Cis-DNA elements can include exon-intron boundary core consensus nucleotides (e.g., GT at +1 and +2 of the 5' donor site and AG at -1 and -2 of the 3' acceptor site) or intronic-exonic nucleotides adjacent to these invariant nucleotides that are highly conserved and found to be involved in splice site selection (e.g., CAG / GUAAGU in the donor site and NYAG / G in the acceptor site). Nucleotide changes in any of these elements can lead to errors in splice site recognition, creating new splice sites or activating cryptic splice sites, resulting in aberrant transcripts or non-functional proteins associated with disease and illness. In some embodiments, at least one targeting moiety of the one or more targeting moieties is sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene. In some embodiments, the consensus sequence comprises about 2 to about 15 nucleotides, about 2 to about 10 nucleotides, or about 2 to about 8 nucleotides. In some embodiments, at least two targeting moieties of the one or more targeting moieties are sufficiently identical to or complementary to at least two consensus sequences in the target sequence of the target gene. In some embodiments, the one or more targeting moieties are each independently sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene.

[0016] In some embodiments of the engineered polynucleotides described herein, one or more targeting moieties each independently comprise from about 2 to about 15 nucleotides, from about 2 to about 10 nucleotides, or from about 2 to about 8 nucleotides. In some embodiments of the engineered polynucleotides described herein, one or more targeting moieties each independently comprise from about 2, 3, 4, 5, 6, 7, 8, 9, or 10 nucleotides.

[0017] In some embodiments of the engineered polynucleotides described herein, the one or more targeting moieties include (1) a first targeting moiety configured to specifically bind to a first targeted sequence in a target sequence of an RNA (e.g., an mRNA, such as a pre-mRNA), and (2) a second targeting moiety configured to specifically bind to a second targeted sequence in a target sequence of an RNA (e.g., an mRNA, such as a pre-mRNA). In some embodiments, the first targeted sequence includes a consensus sequence in the target sequence. In some embodiments, the consensus sequence in the first targeted sequence includes about 2 to about 15 nucleotides, about 2 nucleotides to about 10 nucleotides, or about 2 nucleotides to about 8 nucleotides. In some embodiments, the consensus sequence in the first targeted sequence includes 2 to 3, 3 to 4, 4 to 5, 5 to 6, 6 to 7, 7 to 8, or 8 to 10 nucleotides. In some embodiments, the second targeted sequence includes a consensus sequence in the target sequence. In some embodiments, the consensus sequence of the second targeted sequence comprises about 2 to about 15 nucleotides, about 2 to about 10 nucleotides, or about 2 to about 8 nucleotides. In some embodiments, the consensus sequence of the second targeted sequence comprises 2 to 3, 3 to 4, 4 to 5, 5 to 6, 6 to 7, 7 to 8, or 8 to 10 nucleotides. In some embodiments, the consensus sequence of the first targeted sequence and the consensus sequence of the second targeted sequence differ in nucleotide length. In some embodiments, one of the consensus sequences of the first and second targeted sequence comprises about 1 to about 5 nucleotides, and the other of the consensus sequences of the first and second targeted sequence comprises about 4 to about 8 nucleotides. In some embodiments, one of the consensus sequences of the first and second targeted sequence comprises at least about 2 nucleotides, and the other of the consensus sequences of the first and second targeted sequence comprises at least about 5 or about 6 nucleotides.In some embodiments, one of the consensus sequences of the first and second targeted sequences comprises about 2 nucleotides, and the other of the consensus sequences of the first and second targeted sequences comprises about 5 or about 6 nucleotides.

[0018] In some embodiments of the engineered polynucleotides described herein, the first targeting moiety and the second targeting moiety are different in nucleotide length. In some embodiments, one of the first targeting moiety and the second targeting moiety comprises about 1 to about 5 nucleotides, and the other of the first targeting moiety and the second targeting moiety comprises about 4 to about 8 nucleotides. In some embodiments, one of the first targeting moiety and the second targeting moiety comprises at least about 2 nucleotides, and the other of the first targeting moiety and the second targeting moiety comprises about 5 or 6 nucleotides. In some embodiments, one of the first targeting moiety and the second targeting moiety comprises about 2 nucleotides, and the other of the first targeting moiety and the second targeting moiety comprises about 5 or 6 nucleotides.

[0019] In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence having at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more than 10 nucleotides. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence having up to 10, 9, 8, 7, 6, 5, 4, 3, or 2 nucleotides. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range between any two of the aforementioned values.

[0020] In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an exon that is immediately adjacent to an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an exon that is adjacent to or immediately adjacent to an intron that is located at the 3' end of the exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an exon that is adjacent to or immediately adjacent to an intron that is located at the 5' end of the exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG-3' that targets a nucleotide present in an exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide of an exon that is immediately adjacent to an intron that is present at the 5' end of the exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG-3' that targets nucleotides present in an exon adjacent to an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets nucleotides of an exon immediately adjacent to an intron that are present at the 5' end of the exon.In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG3' that targets a nucleotide present in an exon that is 5' to an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 3'-GG3' that targets a nucleotide present in an exon that is 3' to an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG-3' that targets a nucleotide present in an exon that is not immediately adjacent to an intron.

[0021] In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an intron that is immediately adjacent to an exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an intron that is adjacent to or immediately adjacent to an exon that is located at the 5' end of the intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide in an intron that is adjacent to or immediately adjacent to an exon that is located at the 5' end of the intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence that targets a nucleotide located entirely within an intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG-3' that targets a nucleotide present in an intron adjacent to the exon. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG3' that is present in an intron and targets a nucleotide immediately adjacent to an exon present at the 5' end of the intron.In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 3'-GG3' that is present in an intron and targets a nucleotide immediately adjacent to an exon present at the 3' end of the intron. In some embodiments, the (e.g., first or second) targeting moiety comprises a nucleic acid sequence comprising 5'-AA-3', 5'-AT-3', 5'-AC-3', 5'-AG-3', 5'-TA-3', 5'-TT-3', 5'-TC-3', 5'-TG-3', 5'-CA-3', 5'-CT-3', 5'-CC-3', 5'-CG-3', 5'-GA-3', 5'-GT-3', 5'-GC-3', or 5'-GG-3' that targets a nucleotide present in an intron that is not adjacent to an exon.

[0022] In some embodiments of the engineered polynucleotides described herein, the (e.g., first or second) targeting moiety comprises a sequence that is at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence set forth in Table 1. In some embodiments of the engineered polynucleotides described herein, the (e.g., first or second) targeting moiety comprises a sequence that is identical to or complementary to a sequence set forth in Table 1. In some embodiments, the (e.g., first or second) targeting moiety comprises a sequence that is at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence selected from the 5' targeting moiety sequence column of Table 1 and the 3' targeting moiety sequence column of Table 1. In some embodiments, the (e.g., first or second) targeting moiety comprises a sequence that is identical to or complementary to a sequence selected from the 5' targeting moiety sequence column of Table 1 and the 3' targeting moiety sequence column of Table 1.

[0023] In some embodiments, the first targeting moiety has a sequence that is at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence selected from the 5' targeting moiety sequences column of Table 1. and the second targeting moiety comprises a sequence at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence selected from the 5' targeting moiety sequence column of Table 1, and the second targeting moiety comprises a sequence identical to or complementary to a sequence set forth in the 3' targeting moiety sequence column of Table 1. In some embodiments, the first targeting moiety has a sequence that is at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence set forth in the 3' targeting moiety sequence column of Table 1. and the second targeting moiety comprises a sequence at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to or complementary to a sequence set forth in the 3' targeting moiety sequence column of Table 1. In some embodiments, the first targeting moiety comprises a sequence identical to or complementary to a sequence set forth in the 5' targeting moiety sequence column of Table 1.In some embodiments, the (e.g., first or second) targeting moiety comprises a sequence identical to or complementary to a consensus sequence of an intron donor site (e.g., selected from GU, GT, GC, and CA). In some embodiments, the (e.g., first or second) targeting moiety comprises a sequence identical to or complementary to a consensus sequence of an exon donor site (e.g., G). In some embodiments, the (e.g., first or second) targeting moiety comprises a sequence identical to or complementary to a consensus sequence selected from GU, GC, G, and CA.

[0024] [Table 1]

[0025] Example consensus sequences include: (e.g., 5'-) intron donor site #1: GU; (e.g., 5'-) intron donor site #2: GC; (e.g., 5'-) exon donor site #1: G; and (e.g., 5'-) intron donor site #3: CA.

[0026] Target sequence In some embodiments of the engineered polynucleotides described herein, the first targeting sequence and the second targeting sequence are separated in the target sequence by a spacing sequence of no more than 5, 4, or 3 nucleotides (e.g., 1 or 2 nucleotides).

[0027] In some embodiments of the engineered polynucleotides described herein, the first target sequence and the second target sequence are contiguous or adjacent to one another.

[0028] In some embodiments, if the spacing sequence in the target sequence is adjacent to the 5' or 3' end of the target sequence of the target sequence, the spacing sequence may not be complementary to the targeting portion of the engineered polynucleotide. In some embodiments, if the spacing sequence in the target sequence is adjacent to the 5' or 3' end of the target sequence of the target sequence, the spacing sequence may not be complementary to any targeting portion of the engineered polynucleotide.

[0029] In some embodiments, the spacing sequence separates the first target sequence and the second target sequence described herein.In some embodiments, the spacing sequence is not complementary and does not bind to the targeting portion of the engineered polynucleotide.In some embodiments, the spacing sequence is not complementary and does not bind to all the targeting portions of the engineered polynucleotide.

[0030] In some embodiments of the engineered polynucleotides described herein, the target sequence may comprise an exon-intron boundary in an RNA (e.g., an mRNA, such as a pre-mRNA). In some embodiments, the first target sequence and the second target sequence are both 5' or 3' to the exon-intron boundary. In some embodiments, one of the first target sequence and the second target sequence is 5' to the exon-intron boundary and the other of the first target sequence and the second target sequence is 3' to the exon-intron boundary.

[0031] In some embodiments of the engineered polynucleotides described herein, the target sequence comprises a splice site in an RNA (e.g., an mRNA, such as a pre-mRNA). In some embodiments, the (e.g., first or second) target sequence comprises a splice site (e.g., a 5' splice site) in an RNA (e.g., an mRNA, such as a pre-mRNA).

[0032] In some embodiments, the two target sequences (e.g., the first target sequence and the second target sequence) are part of a single nucleic acid molecule (i.e., an RNA, e.g., an mRNA, such as a pre-mRNA). In some embodiments, the first and second target sequences are spread apart on a single nucleic acid molecule. In some embodiments, the first and second target sequences span an exon-intron boundary of a single nucleic acid molecule. In some embodiments, the first and second target sequences do not span an exon-intron boundary of a single nucleic acid molecule. In some embodiments, the first and second target sequences are adjacent to an exon-intron boundary of a single nucleic acid molecule. In some embodiments, both the first and second target sequences target an intron of a single nucleic acid molecule. In some embodiments, the first and second target sequences span a splice site of a single nucleic acid molecule. In some embodiments, the first and second target nucleic acid sequences do not span a splice site of a single nucleic acid molecule.

[0033] In some embodiments of the engineered polynucleotides described herein, the consensus sequence in the target sequence comprises from about 2 to about 15 nucleotides, from about 2 nucleotides to about 10 nucleotides, or from about 2 nucleotides to about 8 nucleotides.

[0034] In some embodiments, the engineered polynucleotide is complementary to and binds to a target sequence. In some embodiments, at least a portion of the engineered polynucleotide binds to the target sequence. In some embodiments, the target sequence encodes a target gene. A non-limiting example of a target gene may include microtubule associated protein tau (MAPT).

[0035] In some embodiments, the target sequence comprises an RNA sequence. In some embodiments, the RNA is nuclear RNA, cytoplasmic RNA, or mitochondrial RNA. In some embodiments, the target RNA sequence comprises messenger RNA (mRNA), pre-messenger RNA (pre-mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), ribozyme, recombinant polynucleotide, branched polynucleotide, isolated RNA, guide RNA, oligonucleotide, nucleic acid probe, primer, snRNA, long non-coding RNA, small RNA, snoRNA, siRNA, miRNA, tRNA-derived small RNA (tsRNA), antisense RNA, shRNA, or small rDNA-derived RNA (srRNA). In some embodiments, the target RNA sequence is a pre-mRNA. In some embodiments, the engineered polynucleotide is not an antisense oligonucleotide.

[0036] In some embodiments, the target RNA sequence comprises at least one exon. In some embodiments, the target RNA sequence comprises at least one intron. In some embodiments, the target RNA sequence comprises at least one exon or at least one intron. In some embodiments, the target RNA sequence comprises at least one exon-intron boundary.

[0037] In some embodiments, the target sequence is an endogenous nucleic acid molecule. In some embodiments, binding of the engineered polynucleotide to the target sequence is by base pairing, such as Watson-Crick base pairing.

[0038] Mobilization part The recruitment moiety comprises a hairpin structure. The hairpin may be a complete hairpin or may be intercalated by an internal loop. The hairpin structure may consist of 13-17 nucleotides. The recruitment moiety can interact with stem-loop II of U1 snRNA. U1-A can further bind to stem-loop II of U1 snRNA. The hydrogen bridge of stem-loop II with the hairpin / internal loop region can indirectly regulate polyadenylation and acetylation signaling by U1-A. The recruitment moiety may not silence the anchor domain of U1-A in stem-loop II. This interaction can regulate gene expression and acetylation.

[0039] In some embodiments of the engineered polynucleotides described herein, the recruitment portion comprises a nucleotide sequence that is at least 70%, 80%, 85% or 90% identical to, or complementary to, a sequence set forth in Table 2. In some embodiments, the recruitment portion comprises a nucleotide sequence that is identical to, or complementary to, a sequence set forth in Table 2. In some embodiments, the engineered polynucleotide comprises a nucleotide sequence that is at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to, or complementary to, any sequence selected from SEQ ID NOs: 1-4. In some embodiments, the engineered polynucleotide comprises a nucleotide sequence that is at least 70%, 80%, 85%, or 90% identical to, or complementary to, any sequence selected from SEQ ID NOs: 1-4. In some embodiments, the engineered polynucleotide comprises a nucleotide sequence that is identical to, or complementary to, any sequence selected from SEQ ID NOs: 1-4.

[0040] [Table 2]

[0041] In some embodiments described herein, the engineered polynucleotide (e.g., the recruitment portion) comprises a (e.g., secondary) structural feature (see Figures 2A-2D). In some embodiments, the engineered polynucleotide (e.g., the recruitment portion) comprises an apical loop, an upper stem, an internal loop, a lower stem, or a combination thereof. In some embodiments, the engineered polynucleotide (e.g., the recruitment portion) comprises a loop (e.g., an internal loop) adjacent to a stem (e.g., a lower stem, or an upper stem) comprising two complementary stem sequences. In some embodiments, the stem sequence of the stem (e.g., a lower stem, or an upper stem) comprises about 5, 4, or 3 nucleotides or less. In some embodiments, the loop is an internal loop adjacent to a stem (e.g., a lower stem) and an additional stem (e.g., an upper stem) comprising two complementary base sequences. In some embodiments, the internal loop comprises a nucleic acid sequence of 10, 9, or 8 nucleotides or less. In some embodiments, the stem sequence of the additional stem (e.g., upper stem) comprises no more than about 5, 4, or 3 nucleotides. In some embodiments, the engineered polynucleotide (e.g., recruitment moiety) further comprises an apical loop. In some embodiments, the apical loop comprises a nucleic acid sequence of no more than 10, 9, 8, 7, 6, or 5 nucleotides.

[0042] In some embodiments of the engineered polynucleotides described herein, the recruitment portion comprises from about 10 to about 30 nucleotides, from about 10 to about 25 nucleotides, or from about 10 to about 20 nucleotides.

[0043] In some embodiments, the recruitment moiety is partially complementary to a post-transcriptional regulatory moiety (or regulatory moiety) (e.g., a spliceosomal moiety) that comprises a ribonucleoprotein complex. For example, the recruitment moiety can be partially complementary to a regulatory moiety that comprises a spliceosomal ribonucleoprotein complex, which comprises a small nuclear ribonucleic acid (snRNA). In some embodiments, the recruitment moiety is not complementary to and does not bind to a target sequence as described herein. For example, the recruitment moiety is not complementary to and does not bind to a pre-mRNA as described herein.

[0044] structural arrangement In some embodiments of the engineered polynucleotides described herein, one of the first targeting moiety and the second targeting moiety is 5' to the recruitment moiety, and the other of the first targeting moiety and the second targeting moiety is 3' to the recruitment moiety.

[0045] In some embodiments, the engineered polynucleotide has a structural arrangement as follows, from the 5'-end to the 3'-end: a first targeting moiety, a recruitment moiety, and a second targeting moiety. In some embodiments, the engineered polynucleotide has a structural arrangement as follows, from the 5'-end to the 3'-end: a second targeting moiety, a recruitment moiety, and a first targeting moiety.

[0046] Examples of Polynucleotides In some embodiments of the engineered polynucleotides described herein, the engineered polynucleotide comprises about 10 to about 40 nucleotides, about 10 to about 35 nucleotides, about 10 to about 30 nucleotides, or about 10 to about 25 nucleotides. In some embodiments, the engineered polynucleotide comprises at least about 5, 6, 7, 8, 9, 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, or more nucleotides in length. In some embodiments an engineered polynucleotide comprises at least about 5, 6, 7, 8, 9, 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, or less nucleotides in length. In some embodiments, an engineered polynucleotide comprises a length of at least about 5, 6, 7, 8, 9, 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 nucleotides, or a range between any two of the aforementioned values.

[0047] In some embodiments of the engineered polynucleotides described herein, the recruitment portion comprises a nucleotide sequence that is at least 70%, 80%, 85% or 90% identical to, or complementary to, a sequence set forth in Table 3. In some embodiments, the recruitment portion comprises a nucleotide sequence that is identical to, or complementary to, a sequence set forth in Table 3.

[0048] [Table 3]

[0049] In some embodiments, the engineered polynucleotide may be produced from a precursor of the engineered polynucleotide. In some cases, the precursor of the engineered polynucleotide may be linear. For example, the precursor of the engineered polynucleotide may be a linear polynucleotide transcribed from a plasmid. In another example, the precursor of the engineered polynucleotide may be constructed as a linear polynucleotide with a portion, such as a ribozyme portion and a ligation portion, that allows circularization of the engineered polynucleotide in a cell. A linear engineered polynucleotide with a ligation and ribozyme portion can be transfected into a cell and circularized. In some cases, the engineered polynucleotide may be circular. In some cases, the engineered polynucleotide comprises DNA, RNA, or both. In some cases, the precursor of the engineered polynucleotide comprises a precursor of the engineered polynucleotide. In some cases, the precursor of the engineered polynucleotide may be used to produce the engineered polynucleotide.

[0050] In some embodiments, the engineered polynucleotide comprises at least one secondary structure (such as, for example, those described elsewhere herein). For example, the engineered polynucleotide comprises at least one, two, three, four, or more secondary structures, and the secondary structures can be either an apical loop, a stem, a stem loop, or an internal loop, or any combination thereof. In some embodiments, the recruitment portion of the polynucleotide comprises at least one, two, three, four, or more secondary structures. In some embodiments, the targeting portion does not have a secondary structure. In some embodiments, the secondary structure is an apical loop comprising at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more nucleotides. In some embodiments, the apical loop is complementary and binds to the regulatory portion. In some embodiments, the apical loop is not complementary and does not bind to the regulatory portion. In some embodiments, the secondary structure is at least one stem. In some embodiments, the engineered polynucleotide comprises two stems, one an upper stem closer to the apical loop and the other a lower stem closer to the targeting moiety. In some embodiments, the upper stem comprises at least 2, 4, 6, 8, 10, or more nucleotides, and the nucleotides pair to form the upper stem. In some embodiments, the upper stem is complementary and binds to the regulatory moiety. In some embodiments, the upper stem is not complementary and does not bind to the regulatory moiety. In some embodiments, the secondary structure is a lower stem, and the lower stem comprises at least 2, 4, 6, 8, 10, or more nucleotides, and the nucleotides pair to form the lower stem. In some embodiments, the lower stem is complementary and binds to the regulatory moiety. In some embodiments, the lower stem is not complementary and does not bind to the regulatory moiety. In some embodiments, the engineered polynucleotide comprises an internal loop between the upper stem and the lower stem. In some embodiments, the internal loop comprises at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more nucleotides. In some embodiments, the internal loops are complementary to and bind to the regulatory moiety.In some embodiments, the internal loop is not complementary and does not bind to the regulatory portion. In some embodiments, the engineered polynucleotide comprises a secondary structure comprising an apical loop, an upper stem, an internal loop and a lower stem, wherein the upper stem and the internal loop are at least partially complementary and bind to the regulatory portion. In some embodiments, the upper stem and the internal loop are complementary and bind to the regulatory portion comprising a snRNA. In some embodiments, the snRNA is a U1 snRNA, such as a US-A snRNA. In some embodiments, the snRNA is a U2 snRNA.

[0051] In some embodiments, the nucleic acid sequence of the at least one secondary structure is partially complementary to a regulatory portion comprising a ribonucleoprotein complex. In some embodiments, the nucleic acid sequence of the at least one secondary structure is not complementary to a target nucleic acid sequence. In some embodiments, the engineered polynucleotide comprises at least one secondary structure of a nucleic acid. In some embodiments, the engineered polynucleotide comprises at least one, two, three, four, or more secondary structures of a nucleic acid. In some embodiments, the at least one secondary structure increases binding between a recruitment portion and a regulatory portion. In some embodiments, the at least one secondary structure stabilizes assembly of the regulatory portion. In some embodiments, the at least one secondary structure stabilizes assembly of the regulatory portion with other additional portions. In some embodiments, the at least one secondary structure increases efficiency of regulating expression or activity of a gene encoded by a target sequence. In some embodiments, the at least one secondary structure increases specificity of regulating expression or activity of a gene encoded by a target sequence. In some embodiments, the at least one secondary structure increases resistance of the engineered polynucleotide to hydrolytic degradation. In some embodiments, at least one secondary structure increases the resistance of the engineered polynucleotide to degradation by nuclease degradation.In some embodiments, at least one secondary structure increases the half-life of the engineered polynucleotide.In some embodiments, at least one secondary structure reduces the immunogenicity induced by the engineered polynucleotide.

[0052] In some embodiments, the engineered polynucleotide is characterized by a secondary structure. In some embodiments, the secondary structure comprises one or more stem-loop structures. In some embodiments, the secondary structure comprises an apical loop, an upper stem, an internal loop, and a lower stem. In some embodiments, the engineered polynucleotide comprises at least one secondary structure. In some embodiments, the first or second targeting moiety is not part of the secondary structure. In some embodiments, the engineered polynucleotide comprises at least one, two, three, four, or more secondary structures. In some embodiments, the engineered polynucleotide comprises a secondary structure comprising a stem-loop, a cruciform, a toehold, a mismatched bulge, or any combination thereof. In some embodiments, the engineered polynucleotide comprises a secondary structure comprising an apical loop, an upper stem, an internal loop, or a lower stem. In some embodiments, the engineered polynucleotide comprises a secondary structure comprising an apical loop, an upper stem, an internal loop, and a lower stem. In some cases, the secondary structure can include a stem, a hairpin loop, a pseudoknot, a bulge, an internal loop, a multiloop, a G-quadruplex, or any combination thereof. In some embodiments, the engineered polynucleotide can adopt an A-form structure, a B-form structure, a Z-form structure, or any combination thereof. In some embodiments, the secondary structure is formed, at least in part, based on the nucleotide sequence of the engineered polynucleotide. In some embodiments, the secondary structure is formed within the nucleotide sequence of the engineered polynucleotide.

[0053] In some embodiments, at least one secondary structure increases binding between the recruitment moiety and the regulatory moiety, hi some embodiments, at least one secondary structure increases binding between the recruitment moiety and the regulatory moiety by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more, compared to binding between the recruitment moiety and the regulatory moiety without the secondary structure.

[0054] In some embodiments, at least one chemical modification increases binding between the recruitment moiety and the regulatory moiety, hi some embodiments, at least one chemical modification increases binding between the recruitment moiety and the regulatory moiety by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more, compared to binding between the recruitment moiety and the regulatory moiety without the chemical modification.

[0055] In some embodiments, at least one chemical modification of the engineered polynucleotide stabilizes the assembly of spliceosomes containing the regulatory moiety when the regulatory moiety associates with a target sequence. In some embodiments, the assembly of spliceosomes containing the regulatory moiety is stabilized by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more by the engineered polynucleotide containing the chemical modification compared to a comparable polynucleotide that does not contain the chemical modification. In some embodiments, the regulatory moiety is U1 (U1 SNP), U2 (U2 SNP), U4, U5, U6, U11, U12, U14, or U16 of the spliceosome. In some embodiments, the regulatory moiety is U1 SNP of the spliceosome. In some embodiments, the regulatory moiety is U1-A of the spliceosome. In some embodiments, the regulatory moiety is U2 SNP of the spliceosome. In some embodiments, at least one chemical modification of engineered polynucleotide stabilizes the assembly of spliceosomes that comprises regulatory part and at least one additional part.For example, at least one chemical modification of engineered polynucleotide stabilizes the assembly of spliceosomes that comprises regulatory part that comprises U1-A and at least one additional part that comprises U1-70K, UC-1, SmD1, SmD2, SmD3, SmE, SmF or SmG.In some embodiments, at least one additional part is U4, U5, U6, U11, U12, U14 or U16 of spliceosomes.

[0056] In some embodiments, at least one chemical modification increases the efficiency of the engineered polynucleotide to modulate the expression or activity of a gene encoded by a target sequence, as compared to a comparable polynucleotide without the chemical modification. In some embodiments, the efficiency of the engineered polynucleotide to modulate the expression or activity of a gene encoded by a target sequence is increased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more, as compared to a comparable polynucleotide without the chemical modification to modulate the expression or activity of a gene encoded by a target sequence.

[0057] In some embodiments, at least one chemical modification increases the specificity of the engineered polynucleotide to modulate the expression or activity of a gene encoded by a target sequence, as compared to a comparable polynucleotide that does not have the chemical modification. In some embodiments, the specificity of the engineered polynucleotide to modulate the expression or activity of a gene encoded by a target sequence is increased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more, as compared to a comparable polynucleotide that does not have the chemical modification to modulate the expression or activity of a gene encoded by a target sequence.

[0058] In some embodiments, at least one chemical modification increases the resistance of the engineered polynucleotide to hydrolytic degradation. In some embodiments, at least one chemical modification increases the resistance of the engineered polynucleotide to hydrolytic degradation compared to the resistance of a comparable engineered polynucleotide without the chemical modification. In some embodiments, the resistance of the engineered polynucleotide with at least one chemical modification to hydrolytic degradation is increased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to a comparable engineered polynucleotide without the chemical modification.

[0059] In some embodiments, at least one chemical modification increases the resistance of the engineered polynucleotide to nuclease degradation. In some embodiments, at least one chemical modification increases the resistance of the engineered polynucleotide to nuclease degradation compared to the resistance of a comparable engineered polynucleotide without the chemical modification. In some embodiments, the resistance of the engineered polynucleotide with at least one chemical modification to nuclease degradation is increased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to a comparable engineered polynucleotide without the chemical modification.

[0060] In some embodiments, at least one chemical modification increases the half-life of the engineered polynucleotide compared to the half-life of a comparable engineered polynucleotide without the chemical modification. In some embodiments, the half-life of the engineered polynucleotide with at least one chemical modification increases by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to a comparable engineered polynucleotide without the chemical modification. The chemical modification increases the half-life of the engineered polynucleotide.

[0061] In some embodiments, at least one chemical modification reduces the immunogenicity induced by the engineered polynucleotide. In some embodiments, at least one chemical modification reduces the immunogenicity induced by the engineered polynucleotide compared to the immunogenicity of a comparable polynucleotide without chemical modification. In some embodiments, the immunogenicity of the engineered polynucleotide with at least one chemical modification is reduced by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to the immunogenicity of a comparable engineered polynucleotide without chemical modification.

[0062] chemical modification In some embodiments described herein, the engineered polynucleotide comprises at least one chemical modification.

[0063] In some embodiments, all nucleotides of the targeting moiety are linked by phosphorothioate bonds. In some embodiments, all nucleotides of the targeting moiety include 2'O-methyl modifications. The 2' modifications can prevent nuclease degradation and / or increase the affinity of the targeting moiety for the pre-mRNA target.

[0064] In some embodiments, all nucleotides of the recruitment moiety are linked by phosphorothioate bonds. In some embodiments, three nucleotides of the recruitment moiety comprise 2'O-methyl modifications. The 2' modifications can induce fluctuations in the molecular dynamics of the recruitment moiety, thereby promoting the modification of the conformation of stem loop II of U1-snRNA and the binding of the recruitment moiety to U1-snRNA.

[0065] In some embodiments, the engineered polynucleotide comprises at least one 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotide. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are chemically modified nucleotides. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are 2'-modified (e.g., 2'-methoxy, 2'-methoxymethyl, or 2'-methoxyethyl) nucleotides. In some embodiments, the engineered polynucleotide comprises at least one internucleotide phosphorothioate linkage. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages of the engineered polynucleotide are chemically modified. In some embodiments, at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages are phosphorothioate.

[0066] In some embodiments, the engineered polynucleotide comprises at least one chemical modification of the nucleic acid. In some embodiments, the engineered polynucleotide comprises at least one, two, three, or more than three chemical modifications of the nucleic acid. In some embodiments, the at least one chemical modification increases the binding between the recruitment moiety and the regulatory moiety. In some embodiments, the at least one chemical modification stabilizes the assembly of the regulatory moiety. In some embodiments, the at least one chemical modification stabilizes the assembly of the regulatory moiety with other additional moieties. In some embodiments, the at least one chemical modification increases the efficiency of regulating the expression or activity of the gene encoded by the target sequence. In some embodiments, the at least one chemical modification increases the specificity of regulating the expression or activity of the gene encoded by the target sequence. In some embodiments, the at least one chemical modification increases the resistance of the engineered polynucleotide to hydrolytic degradation. In some embodiments, the at least one chemical modification increases the resistance of the engineered polynucleotide to nuclease degradation. In some embodiments, the at least one chemical modification increases the half-life of the engineered polynucleotide. In some embodiments, at least one chemical modification reduces the immunogenicity induced by the engineered polynucleotide.

[0067] In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one substitution of one or both of the non-linked phosphate oxygen atoms in the phosphodiester backbone linkages of the engineered polynucleotide. In some embodiments, the at least one chemical modification of the engineered polynucleotide comprises one or more substitutions of the linking phosphate oxygen atoms in the phosphodiester backbone linkages of the engineered polynucleotide. A non-limiting example of a chemical modification of a phosphate oxygen atom is a sulfur atom. Further non-limiting examples are included in Table 3. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification to a sugar of a nucleotide of the engineered polynucleotide. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification to a sugar of a nucleotide of the engineered polynucleotide, the chemical modification comprising at least one locked nucleic acid (LNA). In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification to a sugar of a nucleotide of the engineered polynucleotide comprising at least one unlocked nucleic acid (UNA). In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification to the sugar comprising a modification of the sugar component, the sugar being a ribose sugar. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification to the ribose sugar component of the nucleotide of the engineered polynucleotide comprising a 2'-O-methyl group. In some embodiments, the chemical modification comprises 2'-F-RNA instead of the 2'-O-methyl group modification. In such cases, the 2'-F-RNA and pre-mRNA duplex does not activate RNase H (degradation by nuclease degradation) and is more stable as determined by a higher melting temperature (Tm) than the 2'-O-methyl RNA and pre-mRNA duplex.

[0068] In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification comprising a substitution of a phosphate moiety of the engineered polynucleotide with a dephosphoryl linker. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification of the phosphate backbone of the engineered polynucleotide. In some embodiments, the engineered polynucleotide comprises a phosphorothioate group. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification comprising a modification to a base of a nucleotide of the engineered polynucleotide. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification comprising a non-natural base of a nucleotide. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification comprising a morpholino group, a cyclobutyl group, a pyrrolidine group, or a peptide nucleic acid (PNA) nucleoside surrogate. In some embodiments, the chemical modification of the engineered polynucleotide comprises at least one chemical modification comprising at least one stereopure nucleic acid. In some embodiments, the at least one chemical modification may be located proximal to the 5' end of the engineered polynucleotide. In some embodiments, at least one chemical modification may be located proximal to the 3' end of the engineered polynucleotide. In some embodiments, at least one chemical modification may be located proximal to both the 5' and 3' ends of the engineered polynucleotide.

[0069] In some embodiments, at least one chemical modification of an engineered polynucleotide comprises a modification of one or both of the non-linked phosphate oxygens in a phosphodiester backbone linkage, a modification of one or more linking phosphate oxygens in a phosphodiester backbone linkage, a modification of a component of the ribose sugar, a replacement of a phosphate moiety with a "dephospho" linker, a modification or replacement of a naturally occurring nucleobase, a modification of the ribose-phosphate backbone, a modification of the 5' end of a polynucleotide, a modification of the 3' end of a polynucleotide, a modification of the deoxyribose phosphate backbone, a replacement of a phosphate group, a modification of the ribophosphate backbone, a modification to the sugar of a nucleotide, a modification to the base of a nucleotide, or a modification of any one or any combination of stereopurities of a nucleotide. Examples of chemical modifications for engineered polynucleotides are shown in Table 4.

[0070] [Table 4-1]

[0071] [Table 4-2]

[0072] Phosphate backbone modification

[0073] In some embodiments, the chemical modification includes modification of one or both of the non-linking phosphate oxygens in the phosphodiester backbone bond, or modification of one or more of the linking phosphate oxygens in the phosphodiester backbone bond. As used herein, "alkyl" is meant to refer to a saturated hydrocarbon group that is straight or branched. Examples of alkyl groups include methyl (Me), ethyl (Et), propyl (e.g., n-propyl, or isopropyl), butyl (e.g., n-butyl, isobutyl, or t-butyl), or pentyl (e.g., n-pentyl, isopentyl, or neopentyl). The alkyl group can contain 1 to about 20, 2 to about 20, 1 to about 12, 1 to about 8, 1 to about 6, 1 to about 4, or 1 to about 3 carbon atoms. As used herein, for example, "aryl" refers to monocyclic, or polycyclic (e.g., having two, three, or four fused rings) aromatic hydrocarbons, such as phenyl, naphthyl, anthracenyl, phenanthrenyl, indanyl, or indenyl. In some embodiments, aryl groups have from 6 to about 20 carbon atoms. As used herein, "alkenyl" refers to an aliphatic group containing at least one double bond. As used herein, "alkynyl" refers to a straight or branched hydrocarbon chain containing from 2 to 12 carbon atoms and characterized by having one or more triple bonds. Examples of alkynyl groups can include ethynyl, propargyl, or 3-hexynyl. "Arylalkyl" or "aralkyl" refers to an alkyl moiety in which an alkyl hydrogen atom is replaced by an aryl group. Aralkyl includes groups in which more than one hydrogen atom is replaced by an aryl group. Examples of "arylalkyl" or "aralkyl" include benzyl, 2-phenylethyl, 3-phenylpropyl, 9-fluorenyl, benzhydryl, and trityl groups. "Cycloalkyl" refers to a cyclic, bicyclic, tricyclic, or polycyclic non-aromatic hydrocarbon group having 3 to 12 carbons. Examples of cycloalkyl moieties include, but are not limited to, cyclopropyl, cyclopentyl, and cyclohexyl. "Heterocyclyl" refers to a monovalent radical of a heterocyclic ring system.Representative heterocyclyls include, but are not limited to, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl, pyrrolidonyl, piperidinyl, pyrrolinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, and morpholinyl. "Heteroaryl" refers to a monovalent radical of an aromatic heterocyclic ring system. Examples of heteroaryl moieties can include imidazolyl, oxazolyl, thiazolyl, triazolyl, pyrrolyl, furanyl, indolyl, thiophenylpyrazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, indolizinyl, purinyl, naphthyridinyl, quinolyl, and pteridinyl.

[0074] In some embodiments, the phosphate group of the chemically modified nucleotide can be modified by replacing one or more oxygens with different substituents. In some embodiments, the chemically modified nucleotide can include replacing the unmodified phosphate moiety with a modified phosphate as described herein. In some embodiments, the modification of the phosphate backbone can include modifications that result in either an uncharged linker or a charged linker with an asymmetric charge distribution. Examples of modified phosphate groups can include phosphorothioates, phosphonothioacetates, phosphoroselenates, boranophosphates, boranophosphate esters, hydrogen phosphonates, phosphoramidates, alkyl or aryl phosphonates and phosphotriesters. In some embodiments, one of the non-bridging phosphate oxygen atoms in the phosphate backbone moiety can be replaced by any of the following groups: sulfur (S), selenium (Se), BR3 (wherein R can be, for example, hydrogen, alkyl, or aryl), C (e.g., alkyl, aryl, etc.), H, NR2 (wherein R can be, for example, hydrogen, alkyl, or aryl), or (wherein R can be, for example, alkyl, or aryl). The phosphorus atom in an unmodified phosphate group can be achiral. However, the replacement of one of the non-bridging oxygens with one of the atoms or groups of atoms described above can make the phosphate atom chiral. Thus, the phosphate atom in a modified phosphate group is an asymmetric center. The asymmetric phosphate atom can have either the "R" configuration (herein Rp) or the "S" configuration (herein Sp). In some cases, the engineered polynucleotide comprises a stereopure nucleotide comprising a phosphorothioate S conformation or a phosphorothioate R conformation. In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 50%, 60%, 70%, 80%, 90%, or more. In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 95%. In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 96%. In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 97%.In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 98%. In some embodiments, the chiral phosphate product is present in a diastereomeric excess of 99%. In some embodiments, both non-bridging oxygens of the phosphorodithioate can be replaced with sulfur. The phosphorus center in the phosphorodithioate can be achiral, which prevents the formation of oligoribonucleotide diastereomeric. In some embodiments, the modification to one or both non-bridging oxygens can further include replacement of the non-bridging oxygen with a group independently selected from S, Se, B, C, H, N, and OR (R can be, for example, alkyl, or aryl). In some embodiments, the phosphate linker can be further modified by replacing the bridging oxygen (i.e., the oxygen that links the phosphate to the nucleoside) with nitrogen (bridging phosphoramidate), sulfur (bridging phosphorothioate), and carbon (bridging methylene phosphonate). Substitution can occur at either or both of the linking oxygens.

[0075] In certain embodiments, the nucleic acid comprises a linked nucleic acid. Nucleic acids can be linked together using any internucleic acid linkage. Two main classes of internucleic acid linkage groups are defined by the presence or absence of a phosphorus atom. Representative phosphorus-containing internucleic acid linkages include, but are not limited to, phosphodiesters, phosphotriesters, methylphosphonates, phosphoramidates, and phosphorothioates (P=S). Representative non-phosphorus-containing internucleic acid linkage groups include, but are not limited to, methylenemethylimino (-CH2-N(CH3)-O-CH2-), thiodiesters (-OC(O)-S-), thionocarbamates (-OC(O)(NH)-S-), siloxanes (-O-Si(H)2-O-); and N,N'-dimethylhydrazine (-CH2-N(CH3)-N(CH3)). In certain embodiments, internucleic acid linkages with chiral atoms can be prepared as separate enantiomers, such as alkylphosphonates and phosphorothioates, to form racemic mixtures. Non-natural nucleic acids can contain a single modification. Non-natural nucleic acids can contain multiple modifications within one of the moieties or between different moieties.

[0076] Backbone phosphate modifications to nucleic acids include, but are not limited to, methylphosphonates, phosphorothioates, phosphoramidates (bridged or non-bridged), phosphotriesters, phosphorodithioates, phosphodithioates, and boranophosphates, which may be used in any combination. Other non-phosphate linkages may also be used.

[0077] In some embodiments, backbone modifications (e.g., methylphosphonate, phosphorothioate, phosphoramidate, and phosphorodithioate internucleotide linkages) can confer immunomodulatory activity to the modified nucleic acid and / or enhance its in vivo stability.

[0078] In some examples, the phosphate derivative (or modified phosphate group) may be attached to a sugar or sugar analog moiety and may be a monophosphate, diphosphate, triphosphate, alkylphosphonate, phosphorothioate, phosphorodithioate, phosphoramidate, or the like.

[0079] In some instances, backbone modifications include replacing phosphodiester linkages with alternative moieties such as anionic, neutral, or cationic groups. Examples of such modifications include the following: anionic internucleoside linkages, N3'-P5' phosphoramidate modifications, boranophosphate DNA, prooligonucleotides, neutral internucleoside linkages such as methyl phosphonates, amide-linked DNA, methylene (methylimino) linkages, formacetal and thioformacetal linkages, backbones containing sulfonyl groups, morpholino oligos, peptide nucleic acids (PNAs), and positively charged deoxyribonucleic acid guanidine (DNG) oligos. Modified nucleic acids can include chimeric or mixed backbones that include one or more modifications, e.g., a combination of phosphate linkages, such as a combination of phosphodiester and phosphorothioate linkages.

[0080] Substituents of the phosphate include, for example, short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatom or heterocyclic internucleoside linkages. These include molnolino linkages (formed in part from the sugar portion of the nucleoside); siloxane backbones; sulfide, sulfoxide, and sulfone backbones; formacetyl and thioformacetyl backbones; methyleneformacetyl and thioformacetyl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others with mixed N, O, S, and CH2 component moieties. It is also understood by nucleotide substitution that both the sugar and phosphate moieties of the nucleotide can be replaced, for example, with aminoethylglycine (PNA). It is also possible to link other types of molecules (conjugates) to nucleotides or nucleotide analogs, for example to enhance cellular uptake. Conjugates can be chemically bound to nucleotides or nucleotide analogs. Such conjugates include, but are not limited to, lipid moieties (cholesterol moieties, thioethers (e.g., hexyl-S-tritylthiol), thiocholesterol, aliphatic chains (e.g., dodecanediol or undecyl residues), phospholipids (e.g., di-hexadecyl-rac-glycerol or triethylammonium l-di-O-hexadecyl-rac-glycero-SH-phosphonate, polyamines or polyethylene glycol chains, etc.), or adamantane acetic acid, palmityl moieties, or octadecylamine or hexylamino-carbonyl-oxycholesteryl moieties.

[0081] In some embodiments, the chemical modifications described herein include modifications of the phosphate backbone. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified phosphate backbone. Examples of chemical modifications of the phosphate group or backbone can include replacing one or more oxygens with different substituents. Additionally, modified nucleotides present in the engineered polynucleotide can include replacing unmodified phosphate moieties with modified phosphates as described herein. In some embodiments, modifications of the phosphate backbone can include modifications that result in either uncharged linkers or charged linkers with asymmetric charge distribution. Examples of modified phosphate groups can include phosphorothioates, phosphonothioacetates, phosphoroselenates, boranophosphates, boranophosphate esters, hydrogen phosphonates, phosphoramidates, alkyl, or aryl phosphonates, and phosphotriesters. In some embodiments, one of the phosphate oxygen atoms in the phosphate backbone can be replaced by any of the following groups: sulfur (S), selenium (Se), BR3 (where R can be, for example, hydrogen, alkyl, or aryl), C (e.g., alkyl, aryl, etc.), H, NR2 (where R can be, for example, hydrogen, alkyl, or aryl), or OR (where R can be, for example, alkyl, or aryl). The phosphorus atom in an unmodified phosphate group can be achiral. However, replacing one of the non-bridging oxygens with one of the above atoms or groups of atoms can make the phosphate atom chiral, i.e., the phosphate atom in the modified phosphate group is thus an asymmetric center. The asymmetric phosphate atom can have either the "R" configuration (herein Rp) or the "S" configuration (herein Sp). In such cases, the chemically modified engineered polynucleotide can be stereopure (e.g., S or R confirmed). In some cases, the chemically modified engineered polynucleotide includes a stereopure phosphate modification. For example, chemically engineered polynucleotides include phosphorothioate S conformations or phosphorothioate R conformations.

[0082] In dithiophosphoric acids, both non-bridging oxygens are replaced with sulfur. The phosphorus center in phosphorodithioates can be achiral, which prevents the formation of oligoribonucleotide diastereomers. In some embodiments, the modification to one or both non-bridging oxygens can further include replacement of the non-bridging oxygen with a group independently selected from S, Se, B, C, H, N, and OR (R can be, for example, alkyl, or aryl).

[0083] In some embodiments, the phosphate linker can be further modified by replacing the bridging oxygen (i.e., the oxygen that connects the phosphate to the nucleoside) with nitrogen (bridging phosphoramidates), sulfur (bridging phosphorothioates), and carbon (bridging methylene phosphonates). Substitutions can occur at either the linking oxygen or both linking oxygens.

[0084] Exchange of phosphate moieties

[0085] In some embodiments, at least one phosphate group of the engineered polynucleotide may be chemically modified. In some embodiments, the phosphate group may be replaced by a non-phosphorus-containing connector. In some embodiments, the phosphate moiety may be replaced by a dephosphoryl linker. In some embodiments, the charged phosphate group may be replaced by a neutral group. In some cases, the phosphate group may be replaced by methylphosphonate, hydroxylamino, siloxane, carbonate, carboxymethyl, carbamate, amide, thioether, ethylene oxide linker, sulfonate, sulfonamide, thioformacetal, formacetal, oxime, methyleneimino, methylenemethylimino, methylenehydrazo, methylenedimethylhydrazo, and methyleneoxymethylimino. In some embodiments, the nucleotide analogs described herein may be further modified at the phosphate group. The modified phosphate moieties may include modifications at the bond between the two nucleotides with phosphorothioates, chiral phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkylphosphotriesters, methyl and other alkyl phosphonates including 3'-alkylene phosphonates and chiral phosphonates, phosphinates, phosphoramidates (e.g., 3'-amino phosphoramidates and aminoalkyl phosphoramidates), thionophosphoramidates, thionoalkylphosphonates, thionoalkylphosphotriesters, and boranophosphates. The phosphate bond or modified phosphate bond between the two nucleotides may be via a 3'-5' or 2'-5' bond, and the bond contains an inverse polarity, such as 3'-5' to 5'-3' or 2'-5' to 5'-2'.

[0086] Phosphate group replacement

[0087] In some embodiments, the chemical modifications described herein include modifications by phosphate group exchange. In some embodiments, the engineered polynucleotides described herein include at least one chemical modification, including phosphate group replacement or exchange. Examples of phosphate group exchange may include non-phosphorus-containing connectors. In some embodiments, phosphate group replacement or exchange may include replacing a charged phosphate group with a neutral moiety. Examples of moieties that can replace phosphate groups may include methylphosphonate, hydroxylamino, siloxane, carbonate, carboxymethyl, carbamate, amide, thioether, ethylene oxide linker, sulfonate, sulfonamide, thioformacetal, formacetal, oxime, methyleneimino, methylenemethylimino, methylenehydrazo, methylenedimethylhydrazo, and methyleneoxymethylimino.

[0088] Modification of the ribonucleic acid backbone

[0089] In some embodiments, the chemical modifications described herein include modifying the ribophosphate backbone of the engineered polynucleotide. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified ribophosphate backbone. Examples of chemically modified ribophosphate backbones can include scaffolds that can mimic nucleic acids, which can be constructed such that the phosphate linker and the ribose sugar are replaced by nuclease-resistant nucleoside or nucleotide surrogates. In some embodiments, the nucleobases can be tethered by the surrogate backbone. Examples can include morpholino, cyclobutyl, pyrrolidine, and peptide nucleic acid (PNA) nucleoside surrogates.

[0090] Sugar modification

[0091] In some embodiments, the chemical modifications described herein include modifying the sugar. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified sugar. Exemplary chemically modified sugars can include 2' hydroxyl groups (OH) modified or replaced with a number of different "oxy" or "deoxy" substituents. In some embodiments, modifications to the 2' hydroxyl group can enhance the stability of the nucleic acid, as the hydroxyl can no longer be deprotonated to form a 2'-alkoxide ion. The 2'-alkoxide can catalyze decomposition by intramolecular nucleophilic attack on the linker atom. Examples of "oxy"-2' hydroxyl group modifications include alkoxy or aryloxy (OR, where "R" can be, for example, alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or sugar); polyethylene glycol (PEG), O(CH2CHO) n It can include CH2CH2OR, where R can be, for example, H or optionally substituted alkyl, and n can be an integer from 0 to 20 (e.g., 0 to 4, 0 to 8, 0 to 10, 0 to 16, 1 to 4, 1 to 8, 1 to 10, 1 to 16, 1 to 20, 2 to 4, 2 to 8, 2 to 10, 2 to 16, 2 to 20, 4 to 8, 4 to 10, 4 to 16, and 4 to 20). In some embodiments, the "oxy"-2' hydroxyl group modification is selected from LNA (where the 2' hydroxyl can be linked to the 4' carbon of the same ribose sugar, e.g., by a Ci-6 alkylene or Cj-6 heteroalkylene bridge, where exemplary bridges can include methylene, propylene, ether, or amino bridges); O-amino (where amino can be, e.g., NH; alkylamino, dialkylamino, heterocyclyl, arylamino, diarylamino, heteroarylamino, or diheteroarylamino, ethylenediamine, or polyamino) and aminoalkoxy, O(CH) n-amino (where amino can be, for example, NH; alkylamino, dialkylamino, heterocyclyl, arylamino, diarylamino, heteroarylamino, or diheteroarylamino, ethylenediamine, or polyamino). In some embodiments, the "oxy"-2' hydroxyl group modification can include a methoxyethyl group (MOE) (OCH2CH2OCH3, e.g., a PEG derivative). In some cases, the deoxy modification can include hydrogen (i.e., the deoxyribose sugar, e.g., in the overhang portion of a partial dsRNA); halo (e.g., bromo, chloro, fluoro, or iodo); amino (where amino can be, for example, NH; alkylamino, dialkylamino, heterocyclyl, arylamino, diarylamino, heteroarylamino, diheteroarylamino, or amino acid); NH(CH2CH2NH) nand alkyl, cycloalkyl, aryl, alkenyl, and alkynyl, which may be optionally substituted with, for example, amino, as described herein. In some examples, the sugar group has the opposite stereochemical configuration to the corresponding carbon in ribose. A modified nucleic acid may further contain one or more carbons having a stereochemical configuration of . Thus, modified nucleic acids may include nucleotides containing, for example, arabinose as the sugar. A nucleotide "monomer" may have an alpha linkage at the Γ position of the sugar, e.g., an alpha-nucleoside. Modified nucleic acids may further include "abasic" sugars that lack a nucleobase at C-. Abasic sugars may be further modified at one or more of the constituent sugar atoms. Modified nucleic acids may further include one or more sugars that are in the L-form, e.g., an L-nucleoside. In some embodiments, In a similar manner, the engineered polynucleotides described herein contain the sugar group ribose, which is a five-membered ring with oxygen. Exemplary modified nucleosides and nucleotides include those that have been modified by replacing the oxygen in ribose (e.g., with sulfur (S), selenium (Se), or an alkylene, such as methylene or ethylene); adding a double-stranded bond (e.g., to replace ribose with a cyclopentenyl or cyclohexenyl); ring contraction of ribose (e.g., to form a cyclobutane or oxetane four-membered ring); ring expansion of ribose (e.g., by adding an additional carbon or heterocyclic ring); The modified nucleotides can include 6- or 7-membered rings having atoms such as anhydrohexitol, altritol, mannitol, cyclohexanyl, cyclohexenyl, and morpholinos, which also have phosphoramidate backbones. In some embodiments, the modified nucleotides can include polycyclic forms (e.g., tricyclo; and "unlocked" forms such as glycol nucleic acids (GNAs) (e.g., R-GNAs or S-GNAs in which the ribose is replaced by glycol units linked to phosphodiester bonds), threose nucleic acids.In some embodiments, modifications to the sugar of the engineered polynucleotide comprise modifying the engineered polynucleotide to include a locked nucleic acid (LNA), a non-locked nucleic acid (UNA), or a bridged nucleic acid (BNA).

[0092] Modification of the building blocks of the ribose sugar

[0093] In some embodiments, the engineered polynucleotides described herein include at least one chemical modification of the ribose sugar building block. In some embodiments, the chemical modification of the ribose sugar building block can include 2'-O-methyl, 2'-O-methoxy-ethyl (2'-MOE), 2'-fluoro, 2'-aminoethyl, 2'-deoxy-2'-fluoroarabinou-cleic acid, 2'-deoxy, 2'-O-methyl, 3'-phosphorothioate, 3'-phosphonoacetate (PACE), or 3'-phosphonothioacetate (thioPACE). In some embodiments, the chemical modification of the ribose sugar building block includes a non-natural nucleic acid. In some examples, the non-natural nucleic acid includes modifications at the 5'-position and the 2'-position of the sugar ring, such as 5'-CH2-substituted 2'-O-protected nucleosides. In some cases, the non-natural nucleic acids include amide-linked nucleoside dimers prepared for incorporation into oligonucleotides, where the 3'-linked nucleoside (5' to 3') in the dimer includes 2'-OCH3 and 5'-(S)-CH3. The non-natural nucleic acids may include 2'-substituted 5'-CH2 (or O) modified nucleosides. The non-natural nucleic acids may include 5'-methylene phosphonate DNA and RNA monomers, and dimers. The non-natural nucleic acids may include 5'-phosphonate monomers with 2'-substitutions, and other modified 5'-phosphonate monomers. The non-natural nucleic acids may include 5'-modified methylene phosphonate monomers. The non-natural nucleic acids may include analogs of 5' or 6'-phosphonate ribonucleosides that include hydroxyl groups at the 5' and / or 6' positions. Non-naturally occurring nucleic acids can include 5'-phosphonate deoxyribonucleoside monomers and dimers having a 5'-phosphate group. Non-naturally occurring nucleic acids can include nucleosides having a 6'-phosphonate group, where the 5' or / and 6'-positions are unsubstituted or substituted with a thio-tert-butyl group (SC(CH3)3) (and analogs), a methyleneamino group (CH2NH2) (and analogs), or a cyano group (CN) (and analogs).

[0094] In some embodiments, the non-natural nucleic acid further comprises a modification of the sugar moiety. In some cases, the nucleic acid contains one or more nucleosides with modified sugar groups. Such sugar-modified nucleosides may confer enhanced nuclease stability, increased binding affinity, or some other beneficial biological property. In certain embodiments, the nucleic acid comprises a chemically modified ribofuranose ring moiety. Examples of chemically modified ribofuranose rings include, but are not limited to, the addition of substitutions (including 5' and / or 2' substituents); bridging of two ring atoms to form bicyclic nucleic acids; the modification of the ribosyl ring oxygen atom with S, N(R), or C(R1)(R2) (R=H, C1-C 12 alkyl, or protecting groups); and combinations thereof.

[0095] In some examples, the engineered polynucleotides described herein include modified sugars or sugar analogs. Thus, in addition to ribose and deoxyribose, the sugar moiety can be pentose, deoxypentose, hexose, deoxyhexose, glucose, arabinose, xylose, lyxose, and sugar "analog" cyclopentyl groups. The sugar can be in pyranosyl or furanosyl form. The sugar moiety can be a furanoside of ribose, deoxyribose, arabinose, or 2'-O-alkylribose, and the sugar can be linked to the respective heterocyclic base in either the [α] or [β] anomeric configuration. Sugar modifications include, but are not limited to, 2'-alkoxy-RNA analogs, 2'-amino RNA analogs, 2'-fluoro DNA, and 2'-alkoxy or amino RNA / DNA chimeras. For example, sugar modifications can include 2'-O-methyl-uridine and 2'-O-methyl-cytidine. Sugar modifications include 2'-O-alkyl substituted deoxyribonucleosides and 2'-O-ethylene glycol-like ribonucleosides.

[0096] Modifications of the sugar moiety include naturally occurring modifications of the ribose and deoxyribose, as well as non-natural modifications. Sugar modifications include, but are not limited to, the following at the 2' position: OH; F; O-alkyl, S-alkyl, or N-alkyl; O-alkenyl, S-alkenyl, or N-alkenyl; O-alkynyl, S-alkynyl, or N-alkynyl; or O-alkyl-O-alkyl, where alkyl, alkenyl, and alkynyl are substituted or unsubstituted C1-C6 alkyl groups. 10 Alkyl or C2-C 10 The 2' sugar modifications further include, but are not limited to, -O[(CH2) n O] m CH3, -O(CH2) n OCH3, -O(CH2) n NH2, -O(CH2) n CH3, -O(CH2) n ONH2 and -O(CH2) n ON [(CH2) n CH3)]2, where n and m are 1 to 10. Other chemical modifications at the 2' position include, but are not limited to, C1-C 10These include lower alkyl, substituted lower alkyl, alkaryl, aralkyl, O-alkaryl or O-aralkyl, SH, SCH3, OCN, Cl, Br, CN, CF3, OCF3, SOCH3, SO2CH3, ONO2, NO2, N3, NH2, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalkylamino, substituted silyl, RNA cleaving groups, reporter groups, intercalators, groups for improving the pharmacokinetic properties of oligonucleotides, groups for improving the pharmacodynamic properties of oligonucleotides, and other substituents with similar properties. Similar modifications can also be made at other positions on the sugar, particularly the 3' position of the sugar on the 3' terminal nucleotide or in 2'-5' linked oligonucleotides, and the 5' position of the 5' terminal nucleotide. Chemically modified sugars further include those that contain modifications at the bridging ring oxygen, such as CH2 and S. Nucleotide sugar analogs can have sugar mimetics, such as cyclobutyl moieties in place of the pentofuranosyl sugar. Examples of nucleic acids with modified sugar moieties include, but are not limited to, nucleic acids containing 5'-vinyl, 5'-methyl (R or S), 4'-S, 2'-F, 2'-OCH3, and 2'-O(CH2)2OCH3 substituents. Substituents at the 2' position include aryl, amino, azido, thio, O-aryl, O-(C1-C 10 Alkyl, OCF3, O(CH2)2SCH3, O(CH2)2-ON(R m )(R n ), and O-CH2-C(=O)-N(R m )(R n ), where R m and R n are each independently H or a substituted or unsubstituted C1-C 10 It is an alkyl.

[0097] In certain embodiments, the nucleic acids of the invention include one or more bicyclic nucleic acids. In certain such embodiments, the bicyclic nucleic acid includes a bridge between the 4' and 2' ribosyl ring atoms. In certain embodiments, the nucleic acids provided herein include one or more bicyclic nucleic acids, in which the bridge includes a 4' to 2' bicyclic nucleic acid. Such 4' to 2' bicyclic nucleic acids include, but are not limited to, one of the following formulas: 4'-(CH2)-O-2' (LNA), 4'-(CH2)-S-2', 4'-(CH2)2-O-2' (ENA), 4'-CH(CH3)-O-2' and 4'-CH(CHOCH3)-O-2' and analogs thereof, 4'-C(CH3)(CH3)-O-2' and analogs thereof.

[0098] Modifications on the nucleotide base

[0099] In some embodiments, the chemical modifications described herein include modifications of the bases (e.g., nucleobases) of nucleotides. Examples of nucleobases can include adenine (A), thymine (T), guanine (G), cytosine (C), and uracil (U). These nucleobases can be modified or replaced in the engineered polynucleotides described herein. The nucleobases of the nucleotides can be independently selected from purines, pyrimidines, purine analogs, or pyrimidine analogs. In some embodiments, the nucleobases can be naturally occurring or synthetic derivatives of the bases.

[0100] In some embodiments, the chemical modifications described herein include modifying uracil. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified uracil. Examples of chemically modified uracils include pseudouridine, pyridin-4-one ribonucleoside, 5-aza-uridine, 6-aza-uridine, 2-thio-5-aza-uridine, 2-thio-uridine, 4-thio-uridine, 4-thio-pseudouridine, 2-thio-pseudouridine, 5-hydroxy-uridine, 5-aminoallyl-uridine, 5-halo-uridine (e.g., 5-iodo-uridine or 5-bromo-uridine), 3-methyl-uridine, 5-methoxy-uridine, ... uridine 5-oxyacetic acid, uridine 5-oxyacetic acid methyl ester, 5-carboxymethyl-uridine, 1-carboxymethyl-pseudouridine, 5-carboxyhydroxymethyl-uridine, 5-carboxyhydroxymethyl-uridine methyl ester, 5-methoxycarbonylmethyl-uridine, 5-methoxycarbonylmethyl-2-thio-uridine, 5-aminomethyl-2-thio-uridine, 5-methylaminomethyl-uridine, 5-methylaminomethyl-2-thio- Uridine, 5-methylaminomethyl-2-seleno-uridine, 5-carbamoylmethyl-uridine, 5-carboxymethylaminomethyl-uridine, 5-carboxymethylaminomethyl-2-thio-uridine, 5-propynyl-uridine, 1-propynyl-pseudouridine, 5-taurinomethyl-uridine, 1-taurinomethyl-pseudouridine, 5-taurinomethyl-2-thio-uridine, 1-taurinomethyl-4-thio-pseudouridine, 5-methyl-uridine, 1-methyl-pseudoundine, 5-methyl-2-thio-uridine, 1-methyl-4-thio-pseudoundine, 4-thio-1-methyl-pseudoundine, 3-methyl-pseudoundine, 2-thio-1-methyl-pseudoundine, 1-methyl-1-deaza-pseudoundine, 2-thio-1-methyl-1-deaza-pseudoundine, dihydroundine, dihydropseudoundine, 5,6-Dihydrouridine, 5-Methyl-dihydrouridine, 2-Thio-dihydrouridine, 2-Thio-dihydropseudouridine, 2-Methoxy-uridine, 2-Methoxy-4-thio-uridine, 4-Methoxy-pseudouridine, 4-Methoxy-2-thio-pseudouridine, N1-Methyl-pseudouridine, 3-(3-amino-3-carboxypropyl)uridine, 1-Methyl-3-(3-amino-3-carboxypropyl)uridine, 5-(isopentenylaminomethyl)uridine, 5-(isopentenylaminomethyl)-2-thio-uridine, a-Thio-uridine, 2'-O-Methyl-uridine, 5,2'-O-Dimethyl-uridine, 2'-O-Methyl-pseudouridine Uridine, 2-thio-2'-O-methyl-uridine, 5-methoxycarbonylmethyl-2'-O-methyl-uridine, 5-carbamoylmethyl-2'-O-methyl-uridine, 5-carboxymethylaminomethyl-2'-O-methyl-uridine, 3,2'-O-dimethyl-uridine, 5-(isopentenylaminomethyl)-2'-O-methyl-uridine, 1-thio-uridine, deoxythymidine, 2'-F-ara-uridine, 2'-F-uridine, 2'-OH-ara-uridine, 5-(2-carbomethoxyvinyl)uridine, 5-[3-(1-E-propenylamino)uridine, pyrazolo[3,4-d]pyrimidine, xanthine, and hypoxanthine.

[0101] In some embodiments, the chemical modifications described herein comprise modifying a cytosine. In some embodiments, the engineered polynucleotides described herein comprise at least one chemically modified cytosine. Examples of chemically modified cytosines are 5-aza-cytidine, 6-aza-cytidine, pseudoisocytidine, 3-methyl-cytidine, N4-acetyl-cytidine, 5-formyl-cytidine, N4-methyl-cytidine, 5-methyl-cytidine, 5-halo-cytidine, 5-hydroxymethyl-cytidine, 1-methyl-pseudoisocytidine, pyrrolo-cytidine, pyrrolo-pseudoisocytidine, 2-thio-cytidine, 2-thio-5-methyl-cytidine, 4-thio-pseudoisocytidine, 4-thio-1-methyl-pseudoisocytidine, 4-thio-1-methyl-1-deaza-pseudoisocytidine, 1-methyl-1-deaza-pseudoisocytidine, zebularine, 5- These may include aza-zebularine, 5-methyl-zebularine, 5-aza-2-thio-zebularine, 2-thio-zebularine, 2-methoxy-cytidine, 2-methoxy-5-methyl-cytidine, 4-methoxy-pseudoisocytidine, 4-methoxy-1-methyl-pseudoisocytidine, lysidine, a-thio-cytidine, 2'-O-methyl-cytidine, 5,2'-O-dimethyl-cytidine, N4-acetyl-2'-O-methyl-cytidine, N4,2'-O-dimethyl-cytidine, 5-formyl-2'-O-methyl-cytidine, N4,N4,2'-O-trimethyl-cytidine, 1-thio-cytidine, 2'-F-ara-cytidine, 2'-F-cytidine, and 2'-OH-ara-cytidine.

[0102] In some embodiments, the chemical modifications described herein include modifying adenine. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified adenine. Examples of chemically modified adenines include 2-amino-purine, 2,6-diaminopurine, 2-amino-6-halo-purine (e.g., 2-amino-6-chloro-purine), 6-halo-purine (e.g., 6-chloi-purine), 2-amino-6-methyl-purine, 8-azido-adenosine, 7-deaza-adenine, 7-deaza-8-aza-adenine, 7-deaza-2-amino-purine, 7-deaza-8-aza-2-amino-purine, 7-deaza-2,6-diaminopurine, 7-deaza-8 -aza-2,6-diaminopurine, 1-methyl-adenosine, 2-methyl-adenine, N6-methyl-adenosine, 2-methylthio-N6-methyl-adenosine, N6-isopentenyl-adenosine, 2-methylthio-N6-isopentenyl-adenosine, N6-(cis-hydroxyisopentenyl)adenosine, 2-methylthio-N6-(cis-hydroxyisopentenyl)adenosine, N6-glycinylcarbamoyl-adenosine, N6-threonylcarbamoyl-adenosine, N6-Methyl-N6-threonylcarbamoyl-adenosine, 2-Methylthio-N6-threonylcarbamoyl-adenosine, N6,N6-Dimethyl-adenosine, N6-Hydroxynorvalylcarbamoyl-adenosine, 2-Methylthio-N6-hydroxynorvalylcarbamoyl-adenosine, N6-Acetyl-adenosine, 7-Methyl-adenine, 2-Methylthio-adenine, 2-Methoxy-adenine, a-Thio-adenosine, 2'-O-Methyl-adenosine, N6,2'-O-Dimethyl-adenosine These may include methyl-adenosine, N6-methyl-2'-deoxyadenosine, N6,N6,2'-O-trimethyl-adenosine, 1,2'-O-dimethyl-adenosine, 2'-O-ribosyladenosine (phosphate) (Ar(p)), 2-amino-N6-methyl-purine, 1-thio-adenosine, 8-azido-adenosine, 2'-F-ara-adenosine, 2'-F-adenosine, 2'-OH-ara-adenosine, and N6-(19-amino-pentaoxanonadecyl)-adenosine.

[0103] In some embodiments, the chemical modifications described herein include modifying guanine. In some embodiments, the engineered polynucleotides described herein include at least one chemically modified guanine. Examples of chemically modified guanosine include inosine, 1-methyl-inosine, wysine, methylwysine, 4-demethyl-wysine, isowyosine, wybutosine, peroxywybutosine, hydroxywybutosine, undemriodified hydroxywybutosine, 7-deaza-guanosine, queuosine, epoxyqueuosine, galactosine, 1-methyl-inos ... Tosyl-queuosine, Mannosyl-queuosine, 7-cyano-7-deaza-guanosine, 7-aminomethyl-7-deaza-guanosine, Archaeosine, 7-deaza-8-aza-guanosine, 6-thio-guanosine, 6-thio-7-deaza-guanosine, 6-thio-7-deaza-8-aza-guanosine, 7-methyl-guanosine, 6-thio-7-methyl-guanosine, 7-methyl-inosine, 6-methoxy-guanosine, 1-methyl-guanosine, N2-methyl-guanosine Anosine, N2,N2-dimethyl-guanosine, N2,7-dimethyl-guanosine, N2,N2,7-dimethyl-guanosine, 8-oxo-guanosine, 7-methyl-8-oxo-guanosine, 1-meththio-guanosine, N2-methyl-6-thio-guanosine, N2,N2-dimethyl-6-thio-guanosine, a-thio-guanosine, 2'-O-methyl-guanosine, N2-methyl-2'-O-methyl-guanosine, N2,N2-dimethyl-2'-O-methyl-guanosine , 1-methyl-2'-O-methyl-guanosine, N2,7-dimethyl-2'-O-methyl-guanosine, 2'-O-methyl-inosine, 1,2'-O-dimethyl-inosine, 6-O-phenyl-2'-deoxyinosine, 2'-O-ribosylguanosine, 1-thio-guanosine, 6-O-methyguanosine, O6-methyl-2'-deoxyguanosine, 2'-F-ara-guanosine, and 2'-F-guanosine.

[0104] In some cases, chemical modification of engineered polynucleotides may include introducing or substituting nucleic acid analogs or non-natural nucleic acids into engineered polynucleotides.In some embodiments, nucleic acid analogs can be any one of the chemically modified nucleic acids described herein.Examples of nucleic acid analogs can be found in PCT / US2015 / 025175, PCT / US2014 / 050423, PCT / US2016 / 067353, PCT / US2018 / 041503, PCT / US18 / 041509, PCT / US2004 / 011786, or PCT / US2004 / 011833, all of which are expressly incorporated by reference in their entirety. Chemically modified nucleotides described herein can include variants of guanosine, uridine, adenosine, thymidine, and cytosine, as well as naturally occurring or non-naturally occurring guanosine, uridine, adenosine, thymidine, or cytidine that have been chemically modified, for example, by acetylation, methylation, hydroxylation. Examples of chemically modified nucleotides are 1-methyl-adenosine, 1-methyl-guanosine, 1-methyl-inosine, 2,2-dimethyl-guanosine, 2,6-diaminopurine, 2'-amino-2'-deoxyadenosine, 2'-amino-2'-deoxycytidine, 2'-amino-2'-deoxyguanosine, 2'-amino-2'-deoxyuridine, 2-amino-6-chloropurine riboside, 2-aminopurine-riboside, 2'-araadenosine, 2'-aracytidine, 2'-arauridine, 2'-azido-2'-deoxyadenosine, 2'-azido-2'-deoxycytidine, 2'-azido-2'-deoxyguanosine, 2 '-azido-2'-deoxyuridine, 2-chloroadenosine, 2'-fluoro-2'-deoxyadenosine, 2'-fluoro-2'-deoxycytidine, 2'-fluoro-2'-deoxyguanosine, 2'-fluoro-2'-deoxyuridine, 2'-fluorothymidine, 2-methyl-adenosine, 2-methyl-guanosine, 2-methyl-thio-N6-isopenenyl-adenosine, 2'-O-methyl-2-aminoadenosine, 2'-O-methyl-2'-deoxyadenosine, 2'-O-methyl-2'-deoxycytidine, 2'-O-methyl-2'-deoxyguanosine, 2'-O-methyl-2'-deoxyuridine,2'-O-methyl-5-methyluridine, 2'-O-methylinosine, 2'-O-methylpseudouridine, 2-thiocytidine, 2-thio-cytidine, 3-methyl-cytidine, 4-acetyl-cytidine, 4-thiouridine, 5-(carboxyhydroxymethyl)-uridine, 5,6-dihydrouridine, 5-aminoallylcytidine, 5-aminoallyl-deoxyuridine, 5-bromouridine, 5-carboxymethylaminomethyl-2-thio-uracil, 5-carboxymethylaminomethyl-uracil, 5-chloro-ara-cytosine, 5-fluoro-uridine, 5-iodouridine, 5-methoxycarbonylmethyl-uridine, 5-methoxy-uridine, 5-methyl-2-thio-uridine, 6-azacytidine, 6-azauridine, 6-chloro-7-deaza-guanosine, 6-chloropurine riboside, 6-mercaptopurine riboside, puto-guanosine, 6-methyl-mercaptopurine riboside, 7-deaza-2'-deoxy-guanosine, 7-deazaadenosine, 7-methyl-guanosine, 8-azaadenosine, 8-bromo-adenosine, 8-bromo-guanosine, 8-mercapto-guanosine, 8-oxoguanosine, benzimidazole-riboside, β-D-mannosyl-queosine, dihydro-uridine, inosine, N1-methyl These may include adenosine, N6-([6-aminohexyl]carbamoylmethyl)-adenosine, N6-isopentenyl-adenosine, N6-methyl-adenosine, N7-methyl-xanthosine, N-uracil-5-oxyacetic acid methyl ester, puromycin, queosine, uracil-5-oxyacetic acid, uracil-5-oxyacetic acid methyl ester, butoxocine, xanthosine and xylo-adenosine. In some embodiments, the chemically modified nucleic acid as described herein is selected from the group consisting of 2-amino-6-chloropurine riboside-5'-triphosphate, 2-aminopurine-riboside-5'-triphosphate, 2-aminoadenosine-5'-triphosphate, 2'-amino-2'-deoxycytidine-triphosphate, 2-thiocytidine-5'-triphosphate, 2-thiouridine-5'-triphosphate, 2'-fluorothymidine-5'-triphosphate, 2'-O-methyl-inosine-5'-triphosphate, 4-thiouridine-5'-triphosphate, 5-aminoallylcytidine-5'-triphosphate, 5-aminoallyluridine-5'-triphosphate,5-bromocytidine-5'-triphosphate, 5-bromouridine-5'-triphosphate, 5-bromo-2'-deoxycytidine-5'-triphosphate, 5-bromo-2'-deoxyuridine-5'-triphosphate, 5-iodocytidine-5'-triphosphate, 5-iodo-2'-deoxycytidine-5'-triphosphate, 5-iodouridine-5'-triphosphate, 5-iodo-2'-deoxyuridine-5'-triphosphate, 5-methylcytidine-5'-triphosphate, 5-methyluridine-5'-triphosphate, 5-propynyl-2'-deoxycytidine-5'-triphosphate, 5-propynyl-2'-deoxyuridine-5'-triphosphate, 6-azacytidine-5'-triphosphate, 6-azauryl The at least one chemically modified nucleotide is selected from lysine-5'-triphosphate, 6-chloropurine riboside-5'-triphosphate, 7-deazaadenosine-5'-triphosphate, 7-deazaguanosine-5'-triphosphate, 8-azaadenosine-5'-triphosphate, 8-azidoadenosine-5'-triphosphate, benzimidazole-riboside-5'-triphosphate, N1-methyladenosine-5'-triphosphate, N1-methylguanosine-5'-triphosphate, N6-methyladenosine-5'-triphosphate, 6-methylguanosine-5'-triphosphate, pseudouridine-5'-triphosphate, puromycin-5'-triphosphate, or xanthosine-5'-triphosphate. In some embodiments, the chemically modified nucleic acid as described herein is selected from the group consisting of pyridin-4-one ribonucleosides, 5-aza-uridine, 2-thio-5-aza-uridine, 2-thiouridine, 4-thio-pseudouridine, 2-thio-pseudouridine, 5-hydroxyuridine, 3-methyluridine, 5-carboxymethyl-uridine, 1-carboxymethyl-pseudouridine, 5-propynyl-uridine, 1-propynyl-pseudouridine, 5-hydroxyur ... Urinomethyluridine, 1-taurinomethyl-pseudouridine, 5-taurinomethyl-2-thio-uridine, 1-taurinomethyl-4-thio-uridine, 5-methyl-uridine, 1-methyl-pseudouridine, 4-thio-1-methyl-pseudouridine, 2-thio-1-methyl-pseudouridine, 1-methyl-1-deaza-pseudouridine, 2-thio-1-methyl-1-deaza-pseudouridine, dihydrouridine, dihydropseudouridine,The artificial nucleic acid as described herein comprises at least one chemically modified nucleotide selected from 2-thio-dihydrouridine, 2-thio-dihydropseudouridine, 2-methoxyuridine, 2-methoxy-4-thio-uridine, 4-methoxy-pseudouridine, and 4-methoxy-2-thio-pseudouridine. In some embodiments, the artificial nucleic acid as described herein comprises at least one chemically modified nucleotide selected from 5-aza-cytidine, pseudoisocytidine, 3-methyl-cytidine, N4-acetylcytidine, 5-formylcytidine, N4-methylcytidine, 5-hydroxymethylcytidine, 1-methyl-pseudoisocytidine, pyrrolo-cytidine, pyrrolo-pseudoisocytidine, 2-thio-cytidine, 2-thio-5-methyl-cytidine, 4-thio-pseudoisocytidine, 4-thio-1-methyl-pseudoisocytidine. The at least one chemically modified nucleotide selected from cytidine, 4-thio-1-methyl-1-deaza-pseudoisocytidine, 1-methyl-1-deaza-pseudoisocytidine, zebularine, 5-aza-zebularine, 5-methyl-zebularine, 5-aza-2-thio-zebularine, 2-thio-zebularine, 2-methoxy-cytidine, 2-methoxy-5-methyl-cytidine, 4-methoxy-pseudoisocytidine, and 4-methoxy-1-methyl-pseudoisocytidine. In some embodiments, the chemically modified nucleic acid as described herein is selected from the group consisting of 2-aminopurine, 2,6-diaminopurine, 7-deaza-adenine, 7-deaza-8-aza-adenine, 7-deaza-2-aminopurine, 7-deaza-8-aza-2-aminopurine, 7-deaza-2,6-diaminopurine, 7-deaza-8-aza-2,6-diaminopurine, 1-methyladenosine, N6-methyladenosine, N6-isopentenyladenosine, N6-(cis- The chemically modified nucleic acid as described herein comprises at least one chemically modified nucleotide selected from: N6-(cis-hydroxyisopentenyl)adenosine, 2-methylthio-N6-(cis-hydroxyisopentenyl)adenosine, N6-glycinylcarbamoyladenosine, N6-threonylcarbamoyladenosine, 2-methylthio-N6-threonylcarbamoyladenosine, N6,N6-dimethyladenosine, 7-methyladenine, 2-methylthio-adenine, and 2-methoxy-adenine. In other embodiments, the chemically modified nucleic acid as described herein comprises at least one chemically modified nucleotide selected from: inosine,The at least one chemically modified nucleotide is selected from 1-methyl-inosine, wyosine, wybutosine, 7-deaza-guanosine, 7-deaza-8-aza-guanosine, 6-thio-guanosine, 6-thio-7-deaza-guanosine, 6-thio-7-deaza-8-aza-guanosine, 7-methyl-guanosine, 6-thio-7-methyl-guanosine, 7-methylinosine, 6-methoxy-guanosine, 1-methylguanosine, N2-methylguanosine, N2,N2-dimethylguanosine, 8-oxo-guanosine, 7-methyl-8-oxo-guanosine, 1-methyl-6-thio-guanosine, N2-methyl-6-thio-guanosine, and N2,N2-dimethyl-6-thio-guanosine. In an embodiment, chemically modified nucleic acids as described herein, 6-aza-cytidine, 2-thio-cytidine, α-thio-cytidine, pseudo-iso-cytidine, 5-aminoallyl-uridine, 5-iodo-uridine, N1-methyl-pseudouridine, 5,6-dihydrouridine, α-thio-uridine, 4-thio-uridine, 6-aza-uridine, 5-hydroxy-uridine, deoxy-thymidine, 5-methyl-uridine, pyrrolo-cytidine, inosine, , α-thio-guanosine, 6-methyl-guanosine, 5-methyl-cytidine, 8-oxo-guanosine, 7-deaza-guanosine, N1-methyl-adenosine, 2-amino-6-chloro-purine, N6-methyl-2-amino-purine, pseudo-iso-cytidine, 6-chloro-purine, N6-methyl-adenosine, α-thio-adenosine, 8-azido-adenosine, 7-deaza-adenosine.

[0105] Modified bases of non-natural nucleic acids include, but are not limited to, uracil-5-yl, hypoxanthine-9-yl (I), 2-aminoadenine-9-yl, 5-methylcytosine (5-me-C), 5-hydroxymethylcytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-methyl and other alkyl derivatives of adenine and guanine, 2-propyl and other alkyl derivatives of adenine and guanine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil and cytosine, 5-propynyluracil and cytosine, 6- These include azo-uracil, cytosine and thymine, 5-uracil (pseudouracil), 4-thiouracil, 8-halo, 8-amino, 8-thiol, 8-thioalkyl, 8-hydroxyl, and other 8-substituted adenines and guanines, 5-halo, especially 5-bromo, 5-trifluoromethyl, and other 5-uracils and cytosines, 7-methylguanine and adenine, 8-azaguanine and adenine, 7-deazaguanine and adenine, and 3-deazaguanine and adenine. Certain non-natural nucleic acids, such as 5-substituted pyrimidines, 6-azapyrimidines, and N-2 substituted purines, N-6 substituted purines, O-6 substituted purines, 2-aminopropyl adenine, 5-propynyl uracil, 5-propynyl cytosine, 5-methyl cytosine, which increase the stability of duplex formation, universal nucleic acids, hydrophobic nucleic acids, promiscuous nucleic acids, size-expanded nucleic acids, fluorinated nucleic acids, 5-substituted pyrimidines, 6-azapyrimidines, and 2-aminopropyl adenine, 5-propynyl uracil, and 5-propynyl cytosine, 5-methyl cytosine (5-me-C), 5- Hydroxymethylcytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-methyl, other alkyl derivatives of adenine and guanine, 2-propyl, other alkyl derivatives of adenine and guanine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil, 5-halocytosine, 5-propynyl (-C≡C-CH3)uracil, 5-propynylcytosine, other alkynyl derivatives of pyrimidine nucleic acids, 6-azouracil, 6-azocytosine, 6-azothymine, 5-uracil (pseudouracil), 4-thiouracil, 8-halo, 8-amino, 8-thiol,8-Thioalkyl, 8-hydroxyl and other 8-substituted adenines and guanines, 5-halo, especially 5-bromo, 5-trifluoromethyl, other 5-substituted uracils and cytosines, 7-methylguanine, 7-methyladenine, 2-F-adenine, 2-amino-adenine, 8-azaguanine, 8-azaadenine, 7-deazaguanine, 7-deazaadenine, 3-deazaguanine, 3-deazaadenine, tricyclic pyrimidines, phenoxazine cytidines ([5,4-b][1,4]benzoxazine- 2(3H)-ones), phenothiazine cytidines (1H-pyrimido[5,4-b][1,4]benzothiazin-2(3H)-ones), G-clamps, phenoxazine cytidines (e.g., 9-(2-aminoethoxy)-H-pyrimido[5,4-b][1,4]benzoxazin-2(3H)-ones), carbazole cytidines (2H-pyrimido[4,5-b]indol-2-ones), pyridoindole cytidines (H-pyrido[3',2':4,5]pyrrolo[2,3-d]pyrimidin-2-ones). including N-2, N-6, and 0-6 substituted purines in which the purine or pyrimidine base is replaced by another heterocycle, 7-deaza-adenine, 7-deazaguanosine, 2-aminopyridine, 2-pyridone, azacytosine, 5-bromocytosine, bromouracil, 5-chlorocytosine, chlorinated cytosine, cyclocytosine, cytosine arabinoside, 5-fluorocytosine, fluoropyrimidine, fluorouracil, 5,6-dihydrocytosine, 5-iodocytosine, hydroxyurea, Iodouracil, 5-nitrocytosine, 5-bromouracil, 5-chlorouracil, 5-fluorouracil, and 5-iodouracil, 2-amino-adenine, 6-thio-guanine, 2-thio-thymine, 4-thio-thymine, 5-propynyl-uracil, 4-thio-uracil, N4-ethylcytosine, 7-deazaguanine, 7-deaza-8-azaguanine, 5-hydroxycytosine, 2'-deoxyuridine, or 2-amino-2'-deoxyadenosine.

[0106] In some cases, the at least one chemical modification may include chemically modifying the 5' or 3' end, such as the 5' cap or 3' tail, of the engineered polynucleotide. In some embodiments, the engineered polynucleotide includes a chemical modification including a 3' nucleotide that may be stabilized against degradation, for example, by incorporating one or more of the modified nucleotides described herein. In this embodiment, the uridine may be replaced with a modified uridine, for example, 5-(2-amino)propyluridine and 5-bromouridine, or any of the modified uridines described herein, and the adenosine and guanosine may be replaced with a modified adenosine and guanosine, for example, a modification at the 8-position, for example, 8-bromoguanosine, or any of the modified adenosines or guanosines described herein. In some embodiments, a deaza nucleotide, for example, 7-deaza-adenosine, may be incorporated into the gRNA. In some embodiments, an O- and N-alkylated nucleotide, for example, N6-methyladenosine, may be incorporated into the gRNA. In some embodiments, sugar-modified ribonucleotides can incorporate, e.g., the 2'OH group can be replaced by a group selected from H, -OR, -R (where R can be, e.g., alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or a sugar), halo, -SH, -SR (where R can be, e.g., alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or a sugar), amino (where amino can be, e.g., NH; alkylamino, dialkylamino, heterocyclyl, arylamino, diarylamino, heteroarylamino, diheteroarylamino, or amino acid; or cyano (-CN). In some embodiments, the phosphate backbone can be modified, e.g., with a phosphothioate group, as described herein.In some embodiments, the nucleotides in the overhang region of the gRNA can each independently be modified or unmodified nucleotides, including but not limited to a 2' sugar modification, such as 2-F2'-O-methyl, thymidine (T), 2'-O-methoxyethyl-5-methyluridine (Teo), 2'-O-methoxyethyl adenosine (Aeo), 2'-O-methoxyethyl-5-methylcytidine (m5Ceo), or any combination thereof.

[0107] In some embodiments, all nucleotides of targeting moiety have 2'O-methyl modification.2'O-methyl modification is believed to increase the affinity of engineered polynucleotide to its pre-mRNA target and / or prevent the degradation of engineered polynucleotide by nuclease.In some embodiments, all nucleotides of targeting moiety have phosphorothioate modification.

[0108] Adjustment part In some embodiments of the engineered polynucleotides described herein, the post-transcriptional regulatory portion (or regulatory portion) (e.g., spliceosomal portion) is selected from a spliceosomal ribonucleoprotein complex, a spliceosomal small nuclear ribonucleic acid (snRNA), a spliceosomal protein, a functional variant thereof, or a functional fragment thereof. In some embodiments, the spliceosomal portion comprises a U1 snRNA and a spliceosomal protein. In some embodiments, the spliceosomal portion comprises a U2 snRNA and a spliceosomal protein. In some embodiments, the spliceosomal snRNA is selected from U1, U2, U4, U5, U6, U11, U12, U14atac, U6atac, and combinations thereof. In some embodiments, the spliceosomal snRNA is U1 or U2. In some embodiments, the spliceosomal protein is selected from Sm, U1-70k, U1A, U1C, and combinations thereof. Non-limiting examples of spliceosomal portions include SmD1, SmD2, SmD3, SmE, SmF, SmG, U1, U2, U4, U5, U6, U11, U12, U14, or U16.

[0109] In some embodiments described herein, upon association with an engineered polynucleotide and an RNA (e.g., an mRNA, such as a pre-mRNA), the spliceosome moiety cleaves or splices the RNA (e.g., an mRNA, such as a pre-mRNA) at the target sequence. In some embodiments, the spliceosome moiety facilitates further modification of the cleaved RNA (e.g., the cleaved mRNA, such as the cleaved pre-mRNA).

[0110] In some embodiments, the binding of the engineered polynucleotide to the target sequence is by base pairing, such as Watson-Crick base pairing. The binding of the engineered polynucleotide provided herein to a recruitment moiety can be utilized to regulate the expression or activity of a target gene. In some embodiments, the binding of the engineered polynucleotide to a recruitment moiety allows the recruitment moiety to splice the pre-mRNA encoding the target gene with increased specificity, thus regulating the target gene. In some embodiments, the binding of the engineered polynucleotide to a recruitment moiety allows the recruitment moiety to splice the pre-mRNA encoding the target gene with increased efficiency, thus regulating the target gene. Regulation can refer to increasing or decreasing the expression or activity of the target gene. A non-limiting example of a target gene can include microtubule-associated protein tau (MAPT). In some embodiments, upon binding of the engineered polynucleotide to the recruitment moiety, the expression or activity of the target gene is increased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to the expression or activity of the target gene in the absence of the engineered polynucleotide bound to the recruitment moiety. In some embodiments, upon binding of the engineered polynucleotide to the recruitment moiety, the expression or activity of the target gene is decreased by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to the expression or activity of the target gene in the absence of the engineered polynucleotide bound to the recruitment moiety.

[0111] In some embodiments, modulating the expression or activity of a target comprises modifying the aberrant expression of a target gene due to a splice variant. In some embodiments, the expression or activity of a misfolded target gene or protein due to an aberrant splice variant is reduced by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more when the engineered polynucleotide binds to the recruitment moiety compared to the expression or activity of a misfolded target gene or protein due to an aberrant splice variant in the absence of the engineered polynucleotide bound to the recruitment moiety. In some embodiments, upon binding of the engineered polynucleotide to the recruitment moiety, the amount of misfolded protein aggregates due to aberrant splice variants is reduced by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to the amount of misfolded protein aggregates due to aberrant splice variants in the absence of the engineered polynucleotide binding to the recruitment moiety. In some embodiments, upon binding of the engineered polynucleotide to the recruitment moiety, the amount of plaques containing misfolded protein due to aberrant splice variants is reduced by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more compared to the amount of plaques containing misfolded protein due to aberrant splice variants in the absence of the engineered polynucleotide binding to the recruitment moiety.

[0112] molecular interactions In some embodiments described herein, the targeting moiety comprises free 5' and 3' ends that interact with conserved sites of the constitutive splice donor. This interaction can silence the U1 snRNA RNA binding domain. In some embodiments, the targeting moiety comprises 2' modified nucleotides that increase affinity for the pre-mRNA target.

[0113] In some embodiments, the binding of the targeting moiety to the pre-mRNA is stabilized by hydrogen bonds and electrostatic interactions between U1-C and the pre-mRNA backbone surrounding the splice junction region of the pre-mRNA. In such embodiments, U1-C may not make specific base contacts with the pre-mRNA. 2' nucleotide modifications may favor hydrogen bonding between the targeting moiety and U1-C. Thus, binding of the targeting moiety (free 5' and 3' ends) to the pre-mRNA duplex allows recognition and stabilization of the targeting interaction by U1-C.

[0114] U1-C can stabilize the spliceosome core. U1-C enhances the affinity of incompatible 5'-splices and stabilizes the spliceosome machinery core through the interaction bridge between U1-70KD and the Sm ring.

[0115] In some embodiments, the targeting moiety can interact with a zinc finger of U1-C, and the phosphorothioate internucleotide linkages of the targeting moiety facilitate the interaction of the targeting moiety with the zinc finger.

[0116] In some embodiments, the recruitment moiety forms a hydrogen bridge to stem-loop II of U1-A. Such an interaction can regulate polyadenylation and acetylation signaling by U1-A, since stem-loop II of U1-A may not be silenced by the recruitment moiety.

[0117] In some embodiments described herein, the engineered polynucleotide does not contain any intramolecular disulfide bonds.

[0118] In some embodiments of the engineered polynucleotides described herein, when associated with the engineered polynucleotide and the spliceosome moiety, the RNA (e.g., mRNA, such as pre-mRNA) exhibits substantially no base pairing with the RNA binding domain (RBD) of U1 snRNA.

[0119] In some embodiments of the engineered polynucleotides described herein, when associated with the engineered polynucleotide and a spliceosome moiety, the RNA (e.g., mRNA, such as pre-mRNA) does not exhibit substantially base-specific interactions with the U1-C protein.

[0120] In some embodiments of the engineered polynucleotides described herein, the engineered polynucleotide is configured to specifically interact with a zinc finger of a U1-C protein, e.g., comprising the following amino acid sequence: YYCDYCDTYLTHDSPSVRKTHCTGRKHRDNVKF (SEQ ID NO: 9). In some embodiments, the 5'-targeting portion of the engineered polynucleotide is configured to specifically interact with a zinc finger of a U1-C protein. In some embodiments, the engineered polynucleotide (e.g., its 5'-targeting portion) is configured to covalently interact with a zinc finger of a U1-C protein (e.g., via a disulfide bond). In some embodiments, the engineered polynucleotide (e.g., its 5'-targeting portion) is configured to non-covalently interact with a zinc finger of a U1-C protein (e.g., via a hydrogen bond).

[0121] In some embodiments, an engineered polynucleotide (e.g., ASMO1 or ASMO2 described herein) comprises a nucleotide sequence complementary to U1 snRNA. In some embodiments of the engineered polynucleotides described herein, the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, a side of the stem loop structure of the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, the subsequence comprises a sequence corresponding to 5'-GGCCU-3' of SL2 of U1 snRNA. In some embodiments, the subsequence does not comprise a sequence corresponding to 5'-CACGUUA-3' of SL2 of U1 snRNA.

[0122] In some embodiments of the engineered polynucleotides described herein, the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the anchor sequence comprises a sequence corresponding to 5'-CACGUUA-3'. In some embodiments, the internal loop of the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the lower stem of the engineered polynucleotide exhibits substantially no base pairing with the anchor sequence of SL2 of U1 snRNA.

[0123] In some embodiments of the engineered polynucleotides described herein, the engineered polynucleotide exhibits substantially no base pairing with the H helix of U1 snRNA.

[0124] In some embodiments, the engineered polynucleotide does not contain intramolecular disulfide bonds. In some embodiments, when the engineered polynucleotide recruits a spliceosome moiety described in a target sequence, such as a target pre-mRNA, the engineered polynucleotide does not exhibit base pairing with the RNA binding domain (RBD) of the spliceosome moiety, such as U1 snRNA. Figure 4 shows such a lack of base pairing between the engineered polynucleotide and the RBD of the spliceosome moiety, where the RBD site of U1 snRNA has the following sequence: 3'-GUCCAUUCAUA-5', which base pairs with the target sequence. In some examples, when the engineered polynucleotide and the spliceosome moiety are combined, the engineered polynucleotide does not exhibit substantially base-specific interactions with the spliceosome moiety of U1-C. In some embodiments, the engineered polynucleotide is configured to specifically interact with a zinc finger of the U1-C protein or a U1-1 spliceosome moiety. FIG. 10C illustrates a representative sequence of the U1-C snRNP, which contains 145 amino acids, with the 36 amino acids that comprise the zinc finger domain (YYCDYCDTYLTHDSPSVRKTHCTGRKHRDNVKF (SEQ ID NO: 9)) highlighted.

[0125] In some embodiments, the engineered polynucleotide is configured to covalently interact with a zinc finger or U1-1 spliceosome portion of the Ul-C protein (e.g., via a disulfide bond). In some embodiments, the engineered polynucleotide is configured to non-covalently interact with a zinc finger or U1-1 spliceosome portion of the Ul-C protein (e.g., via a hydrogen bond). In some embodiments, the engineered polynucleotide (e.g., ASMO1 or ASMO2 described herein) comprises a nucleotide sequence complementary to U1 snRNA. In some embodiments, the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, the side of the stem loop secondary structure of the engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some embodiments, the subsequence comprises a sequence corresponding to 5'-GGCCU-3' of SL2 of U1 snRNA. In some embodiments, the subsequence does not include a sequence corresponding to 5'-CACGUUA-3' of SL2 of U1 snRNA. In some embodiments, the engineered polynucleotide does not exhibit substantially base pairing with the anchor sequence of SL2 of U1 snRNA. In some embodiments, the internal loop of the engineered polynucleotide does not exhibit substantially base pairing with the anchor sequence of SL2 of U1 snRNA. In some aspects, the lower stem of the engineered polynucleotide does not exhibit substantially base pairing with the anchor sequence of SL2 of U1 snRNA. In some aspects, the anchor sequence includes a sequence corresponding to 5'-CACGUUA-3'. In some cases, if the engineered polynucleotide does not include any intramolecular disulfide bonds, the engineered polynucleotide does not exhibit substantially base pairing with the H helix of U1 snRNA. For example, FIG. 2A illustrates the absence of intramolecular disulfide bonds due to the presence of chemical modifications with phosphorothioate internucleotide linkages.Stabilization of the U1 snRNP complex can be observed by the strong ionic attraction of the zinc fingers of U1-C, induced by disulfide bridges with thiols of the targeting moiety of engineered polynucleotide (ASMO) at the 5'-end or / and 3'-end. Although the pre-mRNA / engineered polynucleotide (ASMO) duplex binding can be stabilized by hydrogen bonds and electrostatic interactions between U1-C and the backbone of the pre-mRNA around the seam joint, U1-C does not make base-specific contacts with the pre-mRNA. The structure demonstrates that the selection of nucleotides for 5'-splice by U1 snRNP is achieved mainly through interactions between the stem 5' / 3' and the pre-mRNA. Meanwhile, U1-C adjusts the relative affinity of the mismatched site of 5'-splice and stabilizes the central core of the spliceosome machinery by interaction bridges between U1-70KDa and the Sm ring (see Figure 7-Figure 9). Among the U1 snRNP-specific proteins, U1-70k and U1-C have important roles in aiding in the recognition of pre-mRNA transcripts. U1-70k has a highly conserved but predicted unstructured N-terminus (residues approximately 2-60), an RNA-binding domain (or RBD) that mediates its interaction with the stem-loop of U1 snRNA (residues 92-202), and a C-terminus rich in arginine and serine residues (RS "domain") as well as repeats of R-(D / E) residues. This C-terminal domain is not conserved, but the RS "domain" is important for interaction with non-snRNP splicing factors such as ASF / SF2. The serines in this region are subject to post-translational modification (phosphorylation) and are important for splicing activity. U1-C consists of an N-terminal zinc finger domain and a C-terminal region rich in repeats of RG residues. The arginines in this region of U1-C are subject to post-translational modification (methylation). In contrast to U1-70k, U1-C does not bind free U1 snRNA but requires prior binding of Sm proteins and U1-70k. Mutations in the zinc finger region of U1-C have significant effects on 5' splice site recognition by U1 snRNP, indicating that this protein has a direct role in this activity.The assembly and function of the U1 snRNP has been greatly enhanced, first by cryo-electron microscopy studies and more recently by the elucidation of its three-dimensional structure by X-ray crystallography. Previously, crystal structures of four of the seven Sm proteins led to the modeling of the remaining three (SmF, SmE, and Smg) and the proposal that they interact to form a seven-membered ring. The crystal structure of the complete recombinant human U1 snRNP revealed that the Sm proteins form a heptameric ring composed of a single copy of each Sm protein, through the center of which the Sm site of U1 snRNA passes. In the crystal structure, U1-C is in position to recognize the duplex formed when the 5' end of U1 snRNA base-pairs with the 5' splice site. Thus, the finding that the N-terminus of U1-70k extends 180 Å from the RBD and wraps around one face of the Sm ring across Sm-D2 and Sm-D3 / B could ensure the proper structure and positioning of U1-C for interaction with the U1 snRNA:5′ splice site duplex ( Figure 9 ).

[0126] In some embodiments, when the engineered polynucleotide is associated with the spliceosome moiety described herein, the pre-mRNA exhibits substantially no base pairing with the RNA binding domain (RBD) of U1 snRNA. In some cases, the engineered polynucleotide exhibits substantially no base pairing with the spliceosome moiety and the pre-mRNA exhibits substantially no base-specific interaction with the U1-C protein. Figure 4 illustrates that in the absence of the engineered polynucleotide, the RBD of U1 snRNA binds at the conserved region of the constitutive donor. Meanwhile, in the presence of the engineered polynucleotide, the stem '5 / 3' blocked the RBD interaction of U1 snRNA with the pre-mRNA (Figures 3 and 6).

[0127] In some embodiments, the engineered polynucleotide is configured to specifically interact with the zinc finger of the U1-C protein. In some embodiments, the 5'-targeting portion of the engineered polynucleotide is configured to specifically interact with the zinc finger of the U1-C protein. In some embodiments, the engineered polynucleotide is configured to covalently interact with the zinc finger of the U1-C protein of the Ul-C protein (e.g., via a disulfide bond). In some embodiments, the engineered polynucleotide is configured to non-covalently interact with the zinc finger of the Ul-C protein (e.g., via a hydrogen bond). The formation of a pre-mRNA / engineered polynucleotide (ASMO) duplex that interacts with amino acid residues from the U1-C zinc finger stabilizes the 5' region (Figure 9). Favorable molecular dynamics can then be observed for the formation of the stem 5' of the engineered polynucleotide by disulfide bonds formed by atoms in the main chain and side chain of the U1-C zinc finger. ASMO exhibits interactions with all cysteines present in the U1-C zinc finger, and strong ionic bonds can also be formed (Figures 9 and 10). Additional exemplary interactions between U1-C and pre-mRNA in the presence or absence of engineered polynucleotides described herein are shown in Table 5.

[0128] [Table 5-1]

[0129] [Table 5-2]

[0130] In some embodiments, an engineered polynucleotide (e.g., ASMO1 or ASMO2 described herein) comprises a nucleotide sequence complementary to U1 snRNA. In some aspects, an engineered polynucleotide comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In another aspect, described herein is a side of the stem loop structure of the engineered polynucleotide, which comprises a nucleotide sequence complementary to a subsequence of stem loop II (SL2) of U1 snRNA. In some cases, the subsequence comprises a sequence corresponding to 5'-GGCCU-3' of SL2 of U1 snRNA, where the subsequence does not comprise a sequence corresponding to 5'-CACGUUA-3' of SL2 of U1 snRNA, and the engineered polynucleotide does not substantially exhibit base pairing with an anchor sequence of SL2 of U1 snRNA. In some aspects, the engineered polynucleotide comprises an internal loop of the engineered polynucleotide, which does not substantially exhibit base pairing with an anchor sequence of SL2 of U1 snRNA. In some embodiments, the engineered polynucleotide comprises a lower stem of the engineered polynucleotide that exhibits substantially no base pairing with an anchor sequence of SL2 of U1 snRNA. In some embodiments, the anchor sequence comprises a sequence corresponding to 5'-CACGUUA-3', and the engineered polynucleotide exhibits substantially no base pairing with the H helix of U1 snRNA.

[0131] Engineered polynucleotide sets Described herein are, in some embodiments, a set of engineered polynucleotides, each independently as described herein. For example, the set of polynucleotides independently includes (i) one or more targeting moieties (as described herein) configured to bind to ribonucleic acid (RNA) (as described herein) (e.g., messenger ribonucleic acid (mRNA) such as pre-messenger ribonucleic acid (pre-mRNA)) at a target sequence as described herein, and (ii) a recruitment moiety (as described herein) configured to recruit a post-transcriptional regulatory moiety (e.g., spliceosome moiety) (as described herein), and the set of engineered polynucleotides is configured to specifically bind to RNA (e.g., mRNA such as pre-mRNA) at a plurality of target sequences, including a target sequence (e.g., as described herein).

[0132] vector Some embodiments described herein include vectors or plasmids that contain a nucleic acid sequence that encodes an engineered polynucleotide described herein.

[0133] In some embodiments described herein, the vectors or plasmids each contain multiple nucleic acid sequences encoding the engineered polynucleotides described herein. In some embodiments, the vectors or plasmids contain multiple nucleic acid sequences encoding more than one engineered polynucleotide described herein. In some embodiments, the vectors or plasmids contain multiple nucleic acid sequences encoding multiple engineered polynucleotides (each independently described herein).

[0134] Pharmaceutical Compositions Described herein, in some embodiments, is a pharmaceutical composition comprising an engineered polynucleotide described herein, or a plasmid, vector, or isolated DNA encoding a sequence thereof. A pharmaceutical composition, as used herein, refers to a mixture of at least one engineered polynucleotide or a vector encoding at least one engineered polynucleotide with other chemical components (i.e., pharma- ceutically acceptable inactive components), such as carriers, excipients, binders, fillers, suspending agents, flavorings, sweeteners, disintegrants, dispersants, surfactants, lubricants, colorants, diluents, solubilizers, moistening agents, plasticizers, stabilizers, penetration enhancers, wetting agents, antifoaming agents, antioxidants, preservatives, or combinations of one or more thereof. Optionally, the composition comprises two or more pharmaceutical compositions as discussed herein. In carrying out the methods of treatment or use provided herein, a therapeutically effective amount of a pharmaceutical composition described herein is administered as a pharmaceutical composition to a mammal suffering from a disease, disorder, or condition to be treated. In some embodiments, the mammal is a human. The therapeutically effective amount varies depending on the severity of the disease, the age and relative health of the subject, the strength of the pharmaceutical composition used, and other factors.The pharmaceutical composition may be used alone or in combination with one or more pharmaceutical compositions as components of a mixture.The pharmaceutical compositions described herein include engineered polynucleotides, compositions, cells contacted with engineered polynucleotides, or cells contacted with engineered polynucleotides and compositions, or combinations thereof.

[0135] The pharmaceutical formulations described herein are administered to a subject by suitable routes of administration, including but not limited to intravenous, intraarterial, oral, parenteral, buccal, topical, transdermal, rectal, intramuscular, subcutaneous, intraosseous, transmucosal, inhalation, or intraperitoneal.The pharmaceutical formulations described herein include but are not limited to aqueous liquid dispersions, self-emulsifying dispersions, solid solutions, liposomal dispersions, aerosols, solid dosage forms, powders, immediate release formulations, release formulations, fast dissolving formulations, tablets, capsules, pills, delayed release formulations, sustained release formulations, pulsed release formulations, multiparticulate formulations, and mixed immediate and controlled release formulations.

[0136] Pharmaceutical compositions, including pharmaceutical compositions, may be manufactured in a conventional manner, such as by means of conventional mixing, dissolving, granulating, dragee-making, pulverizing, emulsifying, encapsulating, entrapment, or compressing processes, by way of example only.

[0137] kit In some embodiments described herein, the kits are kits for using the engineered polynucleotides, compositions, or pharmaceutical compositions described herein. In some embodiments, the kits disclosed herein may be used to treat a disease or condition in a subject. In some embodiments, the kits include a collection of materials or components other than the engineered polynucleotides, compositions, or pharmaceutical compositions. In some embodiments, the kits include components for analyzing and selecting appropriate oligonucleotides for treating a disease or condition. In some embodiments, the kits include components for performing an assay, such as an enzyme-linked immunosorbent assay (ELISA), single-molecular array (Simoa), PCR, or qPCR. The exact nature of the components configured in the kit depends on its intended use. For example, some embodiments are configured for the purpose of treating a disease or condition disclosed herein in a subject. In some embodiments, the kits are configured specifically for the purpose of treating a mammalian subject. In some embodiments, the kits are configured specifically for the purpose of treating a human subject.

[0138] Instructions for use may be included in the kit. In some embodiments, the kit includes instructions for administering the composition to a subject in need thereof. In some embodiments, the kit includes instructions for further manipulating the engineered polynucleotide. In some embodiments, the kit may be frozen or lyophilized during storage or transport and includes instructions for thawing or otherwise restoring biological activity of the engineered polynucleotide. In some embodiments, the kit includes instructions for measuring the effectiveness of the kit for its intended purpose (e.g., therapeutic effectiveness when used to treat a subject).

[0139] Optionally, the kit contains other useful components, such as diluents, buffers, pharma- ceutically acceptable carriers, syringes, catheters, applicators, pipetting or metering devices, dressings, or other useful tools. The assembled materials or components in the kit can be stored and provided to the practitioner in a convenient and suitable manner that maintains their operability and usefulness. For example, the engineered polynucleotide, composition, or pharmaceutical composition can be in dissolved, dehydrated, or lyophilized form. The components are typically contained in suitable packaging materials.

[0140] method Described herein are methods for utilizing engineered polynucleotides (such as those described herein), such as methods for modifying ribonucleic acid (RNA) (e.g., messenger ribonucleic acid (mRNA) such as pre-messenger ribonucleic acid (pre-mRNA)) in a cell. The methods can include contacting a cell with an engineered polynucleotide (such as those described herein) that includes one or more targeting moieties and a recruitment moiety. The one or more targeting moieties can bind to an RNA (e.g., an mRNA such as a pre-mRNA) (e.g., as described herein) at a target sequence (such as those described herein) therein, and the recruitment moiety recruits a post-transcriptional regulatory moiety (e.g., a spliceosome moiety) (such as those described herein) within the vicinity of the target sequence of the RNA (e.g., an mRNA such as a pre-mRNA) to modify the RNA (e.g., an mRNA such as a pre-mRNA) in the cell, thereby resulting in one or more modified RNAs (e.g., one or more modified mRNAs such as one or more modified pre-mRNAs). In some embodiments, the methods modify expression or activity of a target gene. In some embodiments, prior to contacting, the cells exhibit abnormal messenger ribonucleic acid (mRNA) or protein corresponding to the target gene. In some embodiments, the targeting moiety of one or more targeting moieties is sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene (e.g., microtubule-associated protein tau (MAPT)).

[0141] Described herein are methods including methods of modifying ribonucleic acid (RNA) (e.g., messenger ribonucleic acid (mRNA) such as pre-messenger ribonucleic acid (pre-mRNA)) at multiple locations in a cell. The methods can include contacting a cell with a set of engineered polynucleotides (e.g., each independently described herein). The engineered polynucleotide can include one or more targeting moieties and recruitment moieties. The one or more targeting moieties can bind to an RNA (e.g., an mRNA such as a pre-mRNA) (such as those described herein) at multiple target sequences (such as those described herein) therein. Each recruitment moiety can recruit a post-transcriptional regulatory moiety (e.g., a spliceosome moiety) (such as those described herein) within the vicinity of a target sequence of the RNA (e.g., an mRNA such as a pre-mRNA) to modify an RNA (e.g., an mRNA such as a pre-mRNA) in the cell, thereby resulting in one or more modified RNAs (e.g., one or more modified mRNAs such as one or more modified pre-mRNAs). In some embodiments, the method modifies expression or activity of a target gene by modifying (e.g., cleaving or / and chemically modifying) an RNA (e.g., an mRNA such as a pre-mRNA) at multiple locations. In some embodiments, prior to contacting, the cell exhibits an abnormal messenger ribonucleic acid (mRNA) or protein corresponding to the target gene. In some embodiments, one or each of the targeting moieties of the one or more targeting moieties is sufficiently identical to or complementary to a consensus sequence in the target sequence of the target gene (e.g., microtubule-associated protein tau (MAPT)).

[0142] In some embodiments, the method includes delivering an engineered polynucleotide to a cell. In some embodiments, the method includes delivering a polynucleotide encoding the engineered polynucleotide to a cell and then expressing the engineered polynucleotide to modulate expression or activity of a gene encoded by a target sequence described herein. In some embodiments, the method includes using the engineered polynucleotide to treat a disease or condition in a subject in need thereof. The disease or condition may be associated with abnormal expression or activity of a target gene encoded by an RNA (e.g., an mRNA, such as a pre-mRNA). In some embodiments, the RNA (e.g., an mRNA, such as a pre-mRNA) corresponds to a target gene (e.g., microtubule associated protein tau (MAPT)).

[0143] FIG. 1 shows a schematic diagram for identifying splice donors and acceptors for designing nucleotide sequences of engineered polynucleotides, where the engineered polynucleotides or methods described herein represent an improvement over currently available approaches for regulating gene expression or activity to treat a disease or condition. In some embodiments, the methods described herein regulate gene expression or activity by engineered polynucleotides that target transcripts of the disease or condition-causing gene. In some embodiments, the methods described herein include administering an engineered polynucleotide described herein to a subject in need thereof. In some cases, the methods described herein include utilizing an engineered polynucleotide to recruit a regulatory moiety to regulate expression or activity of the disease or condition-causing gene, thereby treating the disease or condition. In some aspects, the methods described herein include utilizing an engineered polynucleotide to stabilize the assembly of a regulatory moiety to regulate expression or activity of the disease or condition-causing gene, thereby treating the disease or condition.

[0144] Described herein, in some embodiments, is a method of delivering an engineered polynucleotide described herein to a cell. In some embodiments, the method comprises directly or indirectly delivering the engineered polynucleotide to a cell. In some embodiments, the method comprises contacting the cell with a composition comprising an engineered polynucleotide described herein. In some embodiments, the method comprises expressing the engineered polynucleotide described herein in the cell. In some embodiments, the engineered polynucleotide or a vector encoding the engineered polynucleotide can be delivered to the cell via any of the transfection methods described herein. In some embodiments, the engineered polynucleotide can be delivered to the cell via the use of an expression vector. In the context of an expression vector, the vector can be readily introduced into the cell described herein by any method in the art. For example, the expression vector can be transferred to the cell by physical, chemical, or biological means.

[0145] Physical methods for introducing engineered polynucleotides or vectors encoding engineered polynucleotides into cells include calcium phosphate precipitation, lipofection, particle bombardment, microinjection, gene gun, electroporation, etc. Methods for producing cells containing vectors and / or exogenous nucleic acids are suitable for the methods described herein. One method for introducing engineered polynucleotides or vectors encoding engineered polynucleotides into host cells is calcium phosphate transfection.

[0146] Chemical means for introducing engineered polynucleotides or vectors encoding engineered polynucleotides into cells can include colloidal dispersion systems such as macromolecular complexes, nanocapsules, microspheres, beads, and lipid-based systems including oil-in-water emulsions, micelles, mixed micelles, spherical nucleic acids (SNAs), liposomes, or lipid nanoparticles. An example of a colloidal system for use as a delivery vehicle in vitro and in vivo is a liposome (e.g., artificial membrane vesicle). Other methods of targeted delivery of state-of-the-art nucleic acids are available, such as delivery of engineered polynucleotides or vectors encoding engineered polynucleotides with targeted nanoparticles.

[0147] When a non-viral delivery system is utilized, an exemplary delivery vehicle is a liposome. The use of lipid formulations is contemplated for the introduction of engineered polynucleotides or vectors encoding engineered polynucleotides into cells (in vitro, ex vivo, or in vivo). In other aspects, the engineered polynucleotides or vectors encoding engineered polynucleotides can be associated with lipids. The lipid-associated engineered polynucleotides or vectors encoding engineered polynucleotides can be encapsulated in the aqueous interior of liposomes, interspersed within the lipid bilayer of liposomes, attached to liposomes via a linking molecule associated with both the liposome and the engineered polynucleotide, entrapped in liposomes, complexed with liposomes, dispersed in a solution containing lipids, mixed with lipids, combined with lipids, contained as a suspension in lipids, contained or complexed with micelles, or otherwise associated with lipids. The lipid, lipid / DNA, or lipid / expression vector-related compositions are not limited to any particular structure in solution. For example, in some embodiments, they exist in bilayer structures as micelles or in "folded" structures. Alternatively, they simply disperse in the solution, forming aggregates that are perhaps not uniform in size or shape. Lipids are fatty substances that, in some embodiments, are naturally occurring lipids or synthetic lipids. For example, lipids include the lipid droplets that naturally occur in cytoplasm, as well as the class of compounds that contain long-chain aliphatic hydrocarbons and their derivatives, such as fatty acids, alcohols, amines, aminoalcohols, and aldehydes.

[0148] Lipids suitable for use are obtained from commercial supplies. Stock solutions of lipids in chloroform or chloroform / methanol are often stored at about -20°C. Chloroform is used as the only solvent because it evaporates more readily than methanol. "Liposome" is a generic term that encompasses a variety of unilamellar and multilamellar lipid vesicles formed by the production of enclosed lipid bilayers or aggregates. Liposomes are often characterized as having a vesicular structure with a thin phospholipid bilayer film and an internal aqueous medium. Multilamellar liposomes have multiple lipid layers separated by aqueous medium. They form spontaneously when phospholipids are suspended in an excess of aqueous solution. The lipid components undergo self-rearrangement prior to the formation of a closed structure, trapping water and dissolved solutes between the lipid bilayers. However, compositions with structures in solution that differ from normal vesicular structures are also encompassed. For example, lipids in some embodiments assume a micellar structure or simply exist as heterogeneous aggregates of lipid molecules. Additionally, lipofectamine nucleic acid complexes are contemplated.

[0149] In some cases, non-viral delivery methods include lipofection, nucleofection, microinjection, biolistics, virosomes, liposomes, immunoliposomes, exosomes, polycation or lipid: cargo conjugates (or aggregates), naked polypeptides (e.g., recombinant polypeptides), naked DNA, artificial virions, and drug-enhanced uptake of polypeptides or DNA. In some embodiments, the delivery method includes conjugating or encapsulating the compositions or engineered polynucleotides described herein with at least one polymer, such as a natural polymer or a synthetic material. The polymer may be biocompatible or biodegradable. Non-limiting examples of suitable biocompatible and biodegradable synthetic polymers may include aliphatic polyesters, poly(amino acids), copoly(ether-esters), polyalkylene oxalates, polyamides, poly(iminocarbonates), polyorthoesters, polyoxaesters, polyamide esters, polyoxaesters containing amine groups, and poly(anhydrides). Such synthetic polymers can be homopolymers or copolymers (e.g., random, block, segmented, graft) of two or more of different monomers, such as lactic acid, lactide, glycolic acid, glycolide, epsilon-caprolactone, trimethylene carbonate, p-dioxanone, etc. In an example, the scaffold can be composed of a polymer that includes glycolic acid and lactic acid, such as a 90 / 10 or 5 / 95 ratio of glycolic acid to lactic acid. Non-limiting examples of naturally occurring biocompatible, biodegradable polymers can include glycoproteins, proteoglycans, polysaccharides, glycosaminoglycans (GAGs) and fragments derived from these components, elastin, laminin, decrorin, fibrinogen / fibrin, fibronectin, osteopontin, tenascin, hyaluronic acid, collagen, chondroitin sulfate, heparin, heparan sulfate, ORC, carboxymethylcellulose, and chitin.

[0150] In some cases, the engineered polynucleotides described herein or vectors encoding engineered polynucleotides can be packaged and delivered to cells via extracellular vesicles. The extracellular vesicles can be any membrane-bound particle. In some embodiments, the extracellular vesicles can be any membrane-bound particle secreted by at least one cell. In some examples, the extracellular vesicles can be any membrane-bound particle synthesized in vitro. In some examples, the extracellular vesicles can be any membrane-bound particle synthesized without cells. In some cases, the extracellular vesicles can be exosomes, microvesicles, retrovirus-like particles, apoptotic bodies, apoptosomes, oncosomes, exophers, enveloped viruses, exomeres, or other very large extracellular vesicles.

[0151] Described herein, in some aspects, is a method for regulating or modifying the expression or activity of a gene encoded by a target sequence in a cell. In some embodiments, the target sequence is a pre-messenger ribonucleic acid (pre-mRNA) in the cell. In some embodiments, the method includes contacting the cell with an engineered polynucleotide comprising one or more targeting moieties and a recruitment moiety. In some embodiments, the one or more targeting moieties bind to the pre-mRNA at a target sequence therein. In some embodiments, the recruitment moiety recruits a post-transcriptional regulatory moiety (e.g., a spliceosomal moiety) within proximity of the target sequence of the pre-mRNA to modify the pre-mRNA in the cell, thereby resulting in one or more modified pre-mRNAs. In some embodiments, the pre-mRNA corresponds to a target gene, such as microtubule-associated protein tau (MAPT). In some embodiments, the method increases the expression or activity of a target gene when the engineered polynucleotide binds to the target sequence and recruits the spliceosomal moiety. In some embodiments, the method reduces expression or activity of a target gene when the engineered polynucleotide binds to the target sequence and recruits spliceosome moieties. In some embodiments, the method modifies an aberrant messenger ribonucleic acid (mRNA) or protein corresponding to the target gene when the engineered polynucleotide binds to and recruits spliceosome moieties to the target sequence.

[0152] In some embodiments, the method includes contacting or delivering two or more engineered polynucleotides to a single cell, each of the engineered polynucleotides comprising one or more targeting moieties configured to bind to two or more target sequences. The two or more target sequences can be located on the same strand of a pre-mRNA encoding a target gene. The two or more target sequences can be located on different strands of a pre-mRNA encoding the same target gene. The two or more target sequences can be located on different strands of a pre-mRNA, each strand of a pre-mRNA encoding a different target gene. In some embodiments, the method includes two or more engineered polynucleotides configured to specifically bind to the pre-mRNA at a plurality of target sequences comprising the target sequence.

[0153] Disclosed herein are methods of treating a disease or condition, in some embodiments, by modulating expression or activity of a target gene in a cell, thereby treating the disease or condition. In some embodiments, the method includes treating the disease or condition by modifying an abnormal messenger ribonucleic acid (mRNA) or a protein corresponding to the target gene. In some embodiments, the disease or condition is associated with an increased expression or activity of any one of the target genes described herein. In some embodiments, the disease or condition is associated with a decreased expression or activity of any one of the target genes described herein. In some embodiments, the disease or condition is associated with an abnormal splicing of a messenger ribonucleic acid (mRNA) or a protein corresponding to any one of the target genes described herein.

[0154] In some embodiments, the engineered polynucleotide or pharmaceutical composition comprising the engineered polynucleotide can be administered alone (e.g., monotherapy) to a subject. In some embodiments, the engineered polynucleotide or pharmaceutical composition comprising the engineered polynucleotide is administered in combination with an additional agent. In some cases, the additional agent, as used herein, is administered alone. The engineered polynucleotide or pharmaceutical composition comprising the engineered polynucleotide and the additional agent can be administered together or sequentially. The combination therapy can be administered within the same day, or can be administered one or more days, weeks, months, or years apart.

[0155] In some embodiments, the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, is a first-line treatment for a disease or disorder. In some embodiments, the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, is a second-line, third-line, or forty-fourth-line treatment. In some embodiments, the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, or more oligonucleotides. Generally, the methods disclosed herein include administering the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, via oral administration. However, in some examples, the methods include administering the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, via intraperitoneal injection. In some examples, the methods include administering the engineered polynucleotide, or pharmaceutical composition comprising the engineered polynucleotide, via intravenous ("iv") administration. It is contemplated that the engineered polynucleotides or pharmaceutical compositions comprising engineered polynucleotides disclosed herein may also be administered by other routes, such as subcutaneous, intramuscular, intradermal, transdermal, intranasal, intralymphatic, rectal, intragastric, or other suitable parenteral administration. In some embodiments, routes for localized delivery closer to the site of injury or inflammation are preferred over systemic routes. The route, dosage, time, and duration of administration of the therapeutic agent may be adjusted. In some embodiments, administration of the therapeutic agent is prior to or after the onset of acute and / or chronic symptoms of the disease or disorder.

[0156] The appropriate dose and dosage to be administered to a subject will be determined by factors including, but not limited to, the particular engineered polynucleotide, composition, or pharmaceutical composition, the disease state and its severity, the identity of the subject requiring treatment (e.g., weight, sex, age), and may be determined depending on the particular circumstances surrounding the case, including, for example, the particular agent being administered, the route of administration, the disease being treated, and the subject being treated.

[0157] The use of absolute or sequential terms, such as "will," "will not," "shall," "shall not," "must," "must not," "first," "initially," "next," "sequently," "before," "after," "lastly," and "final," is intended as examples and not as limitations on the scope of the embodiments disclosed herein.

[0158] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent the terms "including," "includes," "having," "has," "with," or variations thereof are used in either the detailed description and / or claims, such terms are intended to be included in a manner similar to the term "comprising."

[0159] As used herein, the terms "at least one," "one or more," and "and / or" are open-ended terms that are both conjunctive and disjunctive in operation. For example, each of the terms "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.

[0160] As used herein, "or" refers to "and," "or," or "and / or," and may be used both exclusively and inclusively. For example, the term "A or B" can refer to "A or B," "A but not B," "B but not A," and "A and B." In some cases, the context may dictate a particular meaning.

[0161] Any systems, methods, software, and platforms described herein are modular, and thus terms such as "first" and "second" do not necessarily imply a priority, order of importance, or order of action.

[0162] The term "about" when referring to a number or numerical range means that the number or numerical range referred to is an estimate within experimental variability (or within statistical experimental error) and that the number or numerical range may vary, for example, by 1% to 15% of the stated number or numerical range. In the examples, the term "about" refers to ±10% of the stated number or value.

[0163] The terms "increased," "increasing," or "increase" are generally used herein to mean an increase of a statistically significant amount. In some embodiments, the term "increased" or "increase" means an increase of at least 10% compared to a reference level, e.g., an increase of at least about 10%, at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or up to 100%, or any increase between 10-100%, compared to a reference level, standard, or control. Other examples of "increase" include an increase of at least 2-fold, at least 5-fold, at least 10-fold, at least 20-fold, at least 50-fold, at least 100-fold, at least 1000-fold, or more, compared to a reference level.

[0164] "Decreased," "decreasing," or "decrease" are generally used herein to mean a statistically significant amount of decrease. In some embodiments, "decreased" or "decrease" means a decrease of at least 10% compared to a reference level, e.g., at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or up to a 100% decrease compared to a reference level (absent or undetectable levels compared to a reference level), or any decrease between 10-100%. In the context of a marker or condition, these terms mean a statistically significant decrease in such level. The decrease can be, for example, at least 10%, at least 20%, at least 30%, at least 40% or more, and is preferably decreased to a level recognized to be within the normal range for a given disease-free individual.

[0165] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the present invention be limited by the specific examples provided within the specification. Although the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the present invention. Furthermore, it will be understood that all aspects of the present invention are not limited to the specific depictions, configurations, or relative proportions described herein, which depend upon a variety of conditions and variables. It will be understood that various alternatives to the embodiments of the present invention described herein may be utilized in the practice of the present invention. It is therefore contemplated that the present invention shall cover any such alternatives, modifications, variations, or equivalents. The following claims define the scope of the present invention, and it is intended that methods and structures within the scope of the claims, and equivalents thereof, be covered thereby.

[0166] Splicing in neurodegenerative diseases Alzheimer's disease (AD) and other tauopathies represent neurodegenerative disorders. AD is characterized by the presence of amyloid-β plaques and hyperphosphorylated tau aggregates in neurofibrillary tangles, neuropil threads, and neuritic plaques in the brain. Progressive loss of white matter is further observed in areas exhibiting tau pathology (Kneynsberg et al., 2017). Furthermore, literature data indicates that AD is also characterized by depletion, accumulation, and aggregation of U1 snRNP nuclei in the cytoplasm along with splicing impairment (Bai et al., 2013, 2014, 2018; Zhu et al., 2020). Moreover, the basic-acidic dipeptide domain of U1-70K was demonstrated to interact with tau from AD brains, and both U1-70K and tau colocalize in neurofibrillary tangles in late-onset sporadic and familial cases of AD (Bishofet al., 2018).

[0167] In a study integrating data from human postmortem brain tissue and Drosophila melanogaster models, Hsieh and coworkers showed that AD tau neurofibrillary tangle pathology disrupts spliceosome activity, leading to transcriptome dysfunction and ultimately CNS dysfunction and neurodegeneration. The researchers hypothesize that tau is involved in spliceosomal cytoplasmic sequestration and disruption of snRNP assembly and / or stability. They further showed that several spliceosomal components (including U1-70K) physically associate with tau in human brains with AD pathology, and that genetic manipulation of these factors enhances tau neurotoxicity in Drosophila. They confirmed an increased latent splicing load in human postmortem brains with tau pathology (Hsieh et al., 2019).

[0168] References Bai, B., Chen, PC, Hales, CM, Wu, Z., Pagala, V., High, AA, Levey, AI, Lah, JJ, & Peng, J. (2014). Integrated Approaches for Analyzing U1-70K Cleavagein Alzheimer's Disease. Journal of Proteome Research, 13(11), 4526. https: / / doi.org / 10.1021 / PR5003593

[0169] Bai,B.,Hales,C.M.,Chen,P.C.,Gozal,Y.,Dammer,E.B.,Fritz,J.J.,Wang,X.,Xia,Q.,Duong,D.M.,Street,C.,Cantero,G.,Cheng,D.,Jones,D.R.,Wu,Z.,Li,Y.,Diner,I.,Heilman,C.J.,Rees,H.D.,Wu,H.,…Peng,J.(2013).U1 small nuclear ribonucleoprotein complex and RNA splicing alterations in Alzheimer’s disease.Proceedings of the National Academy of Sciences of the United States of America,110(41),16562-16567。https: / / doi.org / 10.1073 / pnas.1310249110

[0170] Bai,B.,Wang,S.,Chen,Y.,Jia,J.,Tian,X.,Liu,C.,Xia,Y.,& Xie,H.(2018).Effects of RNA Splicing Inhibitors on Amyloid PrecursorProtein Expression.ACS Omega,3(3),2798。https: / / doi.org / 10.1021 / ACSOMEGA.7B02073

[0171] Bishof,I.,Dammer,E.B.,Duong,D.M.,Kundinger,S.R.,Gearing,M.,Lah,J.J.,Levey,A.I.,& Seyfried,N.T.(2018).RNA-binding proteins with basic-acidic dipeptide (BAD) domains self-assemble and aggregate in Alzheimer’s disease.The Journal of Biological Chemistry,293(28),11047。https: / / doi.org / 10.1074 / JBC.RA118.001747

[0172] Hsieh,Y.C.,Guo,C.,Yalamanchili,H.K.,Abreha,M.,Al-Ouran,R.,Li,Y.,Dammer,E.B.,Lah,J.J.,Levey,A.I.,Bennett,D.A.,De Jager,P.L.,Seyfried,N.T.,Liu,Z.,& Shulman,J.M.(2019).Tau-Mediated Disruption of the Spliceosome Triggers Cryptic RNA Splicing and Neurodegeneration in Alzheimer’s Disease.Cell Reports,29(2),301-316.e10.。https: / / doi.org / 10.1016 / J.CELREP.2019.08.104

[0173] Kneynsberg,A.,Combs,B.,Christensen,K.,Morfini,G.,& Kanaan,N.M.(2017).Axonal degeneration in tauopathies: Disease relevance and underlying mechanisms.Frontiers in Neuroscience,11(OCT),1-14。https: / / doi.org / 10.3389 / fnins.2017.00572

[0174] Zhu, W., Wei, https: / / doi.org / 10.1021 / acsomega.0c03568 EXAMPLES

[0175] The following illustrative examples are representative of embodiments of the stimuli, systems and methods described herein and are not meant to be limiting in any way.

[0176] Example 1. Modulation of target gene expression using engineered polynucleotides The cells obtained from the cell-like (e.g., HEK293 cell line) are cultured and maintained in cell culture medium. The cells can then be contacted with the engineered polynucleotide or the vector encoding the engineered polynucleotide for delivery of the engineered polynucleotide or the vector encoding the engineered polynucleotide to the cells by any one of the delivery methods described herein. After the engineered polynucleotide is delivered to the cells, the cells can be cultured for a period of time to allow the engineered polynucleotide to regulate the expression or activity of the target gene. The cells can then be harvested and lysed for measurement of the expression or activity of the target gene. For example, the cells can be harvested, lysed, and examined for the abundance of pre-mRNA, mRNA, or protein of the target gene regulated by the engineered polynucleotide. In other cases, the cells can be fixed and prepared for microscopic examination. For example, the cells can be examined under a microscope for the presence or change in abundance of inclusions or amyloid plaques associated with any one of the target genes described herein (e.g., tau plaques encoded by the MAPT target gene).

[0177] Example 2. Treating Neurological Diseases with RNA Editing The subject is diagnosed with Alzheimer's disease resulting from abnormal splicing of tau protein encoded by the target gene MAPT. The subject is prescribed an administration regimen of a pharmaceutical composition comprising a chemically modified engineered polynucleotide disclosed herein to recruit and stabilize at least one regulatory moiety to the target MAPT pre-mRNA. Upon binding to MAPT pre-mRNA, the chemically modified engineered polynucleotide recruits and stabilizes at least one regulatory moiety for accurate splicing of MAPT pre-mRNA. In some embodiments, the chemically modified engineered polynucleotide increases the specificity or efficiency of recruiting and stabilizing at least one regulatory moiety RNA editing entity. Modulation of MAPT pre-mRNA by the engineered polynucleotide reduces the amount of tau plaques in the subject, thereby treating or reducing the symptoms of Alzheimer's disease in the subject.

[0178] Although the foregoing disclosure has been described in some detail for purposes of clarity and understanding, it will be apparent to those skilled in the art from reading this disclosure that various changes in form and detail may be made without departing from the true scope of the present disclosure. For example, all of the techniques and devices described above can be used in various combinations. All publications, patents, patent applications, and / or other documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, and / or other document was individually and separately indicated to be incorporated by reference for all purposes.

[0179] Example 3. Spliceosome regulation by engineered polynucleotides The effect of the chemically engineered polynucleotides described herein on splicing is determined by RNA-Seq.

[0180] The RNA-Seq protocol consists of culturing excitatory neurons derived from iPSCs (induced pluripotent stem cells) from healthy patients (HDC-healthy donor cells) and Alzheimer's disease patients (ADC-Alzheimer's disease donor cells) for 16 days. After 6 days of culture, HDC and ADC neurons are treated for 10 days with two different concentrations of engineered polynucleotides containing targeting and recruitment moieties (e.g., ASMO-1, ASMO-2). Negative controls for both HDC and ADC consist of 10 days of culture in medium without compound treatment. After 16 days of cell culture and treatment, RNA extraction, library preparation, and RNA sequencing are performed. The quantitative goal of the experiment is targeted to 100 million reads per condition. The experiment is performed with three replicates and only one repeat.

[0181] Bioinformatics analysis was performed using the RNA-seq generated raw data, consisting of the following steps: (i) quality control of the raw read data, (ii) mapping against the human reference genome, (iii) transcript quantification and differential expression analysis to determine differentially expressed genes, (iv) gene ontology enrichment analysis, (v) analysis of key pathways (such as pathways associated with TAU and Alzheimer's disease), and (vi) comparison of the differentially expressed genes from RNA-seq with in silico predicted potential targets of ASMO-1.

[0182] RNA-seq data analysis of HDC and ADC negative controls identifies gene expression differences and associated pathways between healthy and Alzheimer's disease cells. These differences observed in HDC and ADC controls are expected to highlight key features and biomarkers of Alzheimer's disease.

[0183] Furthermore, in the treatment conditions tested, the RNA-seq data demonstrates that ASMO-1 (for example) enhances splicing of predicted target candidates such as MAPT pre-mRNA, through differential gene expression analysis, evidence of restoration of expression levels of these candidates in AD-treated cells to healthy levels comparable to HDC controls. Genes abnormally upregulated in ADC controls associated with HDC are downregulated in AD-treated cells, and vice versa. Furthermore, these beneficial expression modulations by ASMO-1 in treated (for example, expected to be represented by TAU expression modulation) AD cells induce an indirect cascade of downstream effects that render the gene expression pattern as a whole more similar to that of HD-untreated cells and less similar to AD-untreated cells and their salient pathways (NFT accumulation, amyloid b cleavage, amyloid beta degradation, APOE-cholesterol pathway, etc.).

[0184] In the context of pharmaceutical safety, we expect that RNA-seq data analysis of HDCs treated with ASMO-1 will ensure that no adverse gene expression profiles are exhibited by the treatment at at least one of the concentrations evaluated.

Claims

1. An engineered polynucleotide comprising: (i) one or more targeting moieties configured to specifically bind to a messenger ribonucleic acid (pre-mRNA) at a target sequence therein; and (ii) a recruitment moiety configured to recruit a spliceosome moiety, wherein when the pre-mRNA associates with the engineered polynucleotide, the spliceosome moiety modifies the pre-mRNA within or proximal to the target sequence. The engineered polynucleotide.

2. The engineered polynucleotide according to claim 1, comprising a top loop, an upper stem, an internal loop, a lower stem, or a combination thereof.

3. An engineered polynucleotide comprising: (i) one or more targeting moieties configured to specifically bind to a messenger ribonucleic acid (pre-mRNA) at a target sequence therein; and (ii) a recruitment moiety configured to recruit a spliceosome moiety, the recruitment moiety comprising a top loop, an upper stem adjacent to the top loop, a lower stem, and an internal loop positioned between the upper stem and the lower stem. The engineered polynucleotide.

4. The engineered polynucleotide according to any one of claims 1 or 3, wherein the targeting moiety of the one or more targeting moieties is sufficiently identical or complementary to a consensus sequence in the target sequence of the target gene.

5. The engineered polynucleotide according to any one of claims 1 or 3, wherein the one or more targeting moieties comprise: (1) a first targeting moiety configured to specifically bind to a first target sequence in the target sequence of the pre-mRNA; and (2) a second targeting moiety configured to specifically bind to a second target sequence in the target sequence of the pre-mRNA. The engineered polynucleotide.

6. The engineered polynucleotide according to claim 5, wherein the first target sequence or the second target sequence comprises a consensus sequence in the target sequence.

7. The engineered polynucleotide according to claim 5, wherein the first target sequence and the second target sequence are separated by a spacer sequence of 5 nucleotides or less in the target sequence.

8. The engineered polynucleotide according to any one of claims 1 or 3, wherein the target sequence comprises an exon-intron boundary in the pre-mRNA. **Claim 9**: The manipulated polynucleotide according to claim 8, wherein both the first target sequence and the second target sequence are either 5' or 3' with respect to the exon-intron boundary, or one of the first target sequence and the second target sequence is 5' with respect to the exon-intron boundary and the other of the first target sequence and the second target sequence is 3' with respect to the exon-intron boundary. **Claim 10**: The manipulated polynucleotide according to any one of claims 1 or 3, wherein the target sequence contains a splice site in the pre-mRNA. **Claim 11**: The manipulated polynucleotide according to claim 5, wherein the first targeting moiety or the second targeting moiety comprises a sequence that is identical or complementary to the consensus sequence of an intron donor site or an exon donor site. **Claim 12**: The manipulated polynucleotide according to any one of claims 1 or 3, wherein the spliceosome moiety is selected from a spliceosome ribonucleoprotein complex, a spliceosome small nuclear ribonucleic acid (snRNA), a spliceosome protein, a functional variant thereof, or a functional fragment thereof. **Claim 13**: The manipulated polynucleotide according to claim 12, wherein the spliceosome moiety comprises U1 snRNA and a spliceosome protein. **Claim 14**: The manipulated polynucleotide according to claim 12, wherein the spliceosome snRNA is selected from U1, U2, U4, U5, U6, U11, U12, U14atac, U6atac, and combinations thereof, or the spliceosome protein is selected from Sm, U1-70k, U1A, U1C, and combinations thereof. **Claim 15**: The manipulated polynucleotide according to any one of claims 1 or 3, wherein the mobilizing moiety comprises a nucleotide sequence that is at least 70%, 80%, 85%, 90%, or 100% identical or complementary to any one of SEQ ID NOs: 1 to 4. **Claim 16**: The engineered polynucleotide according to claim 2 or 3, wherein the stem arrangement of the upper stem or the lower stem comprises a complementary stem arrangement containing about 5, 4, or 3 nucleotides or less, the internal loop comprises a nucleic acid sequence of 10, 9, or 8 nucleotides or less, and / or the apical loop comprises a nucleic acid sequence of 10, 9, 8, 7, 6, or 5 nucleotides or less. **Claim 17**: The engineered polynucleotide according to any one of claims 1 or 3, which does not contain any intramolecular disulfide bonds. **Claim 18**: The engineered polynucleotide according to any one of claims 1 or 3, wherein when the engineered polynucleotide is associated with the spliceosome moiety, the pre-mRNA substantially does not exhibit base pairing with the RNA binding domain (RBD) of U1 snRNA and / or substantially does not exhibit base-specific interaction with the U1-C protein. **Claim 19**: The engineered polynucleotide according to any one of claims 1 or 3, which is configured to specifically interact with the zinc finger of the U1-C protein. **Claim 20**: The engineered polynucleotide according to any one of claims 1 or 3, which contains a nucleotide sequence complementary to a partial sequence of stem-loop II (SL2) of U1 snRNA. **Claim 21**: The engineered polynucleotide according to claim 20, wherein the partial sequence contains a sequence corresponding to 5'-GGCCU-3' of SL2 of U1 snRNA. **Claim 22**: The engineered polynucleotide according to any one of claims 1 or 3, which substantially does not exhibit base pairing with the anchor sequence of SL2 of U1 snRNA and / or base pairing with the H helix of U1 snRNA. **Claim 23**: The engineered polynucleotide according to any one of claims 1 or 3, which contains at least one chemical modification. **Claim 24**: The engineered polynucleotide according to claim 23, which contains at least one 2'-modified nucleotide. **Claim 25**: The engineered polynucleotide according to claim 24, wherein the 2'-modified nucleotide contains 2'-methoxy nucleotide, 2'-methoxymethyl nucleotide, 2'-methoxyethyl nucleotide, 2'-fluoro nucleotide, or 2'-aminoethyl nucleotide. **Claim 26**: The engineered polynucleotide according to claim 24, wherein at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are chemically modified nucleotides. **Claim 27**: The engineered polynucleotide according to claim 24, wherein at least about 50%, 60%, 70%, 80%, or 90% of the nucleotides of the engineered polynucleotide are 2'-modified nucleotides. **Claim 28**: The engineered polynucleotide according to claim 24, comprising at least one phosphorothioate internucleotide linkage. **Claim 29**: The engineered polynucleotide according to claim 24, wherein one or more internucleotide linkages of the engineered polynucleotide are chemically modified. **Claim 30**: The engineered polynucleotide according to any one of claims 1 to 3, comprising nucleotides connected by internucleotide linkages, wherein (i) at least one of the internucleotide linkages comprises sulfur (S), selenium (Se), BR3 (wherein each R is independently selected from the group consisting of hydrogen, alkyl, or aryl), carbon (C), or NR2 (wherein each R is independently selected from the group consisting of hydrogen, alkyl, or aryl), or (ii) at least one of the internucleotide linkages comprises methylphosphonate, hydroxylamino, siloxane, carbonate, carboxymethyl, carbamate, amide, thioether, ethylene oxide linker, sulfonate, sulfonamide, thioformacetal, formacetal, oxime, methyleneimino, methylenemethylimino, methylenehydrazo, methylenedimethylhydrazo, or methyleneoxymethylimino. **Claim 31**: The engineered polynucleotide according to claim 24, wherein at least about 50%, 60%, 70%, 80%, or 90% of the internucleotide linkages are phosphorothioates. **Claim 32**: The engineered polynucleotide according to any one of claims 1 or 3, comprising from about 10 to about 40 nucleotides, from about 10 to about 35 nucleotides, from about 10 to about 30 nucleotides, or from about 10 to about 25 nucleotides.

33. The engineered polynucleotide according to any one of claims 1 or 3, wherein when the engineered polynucleotide associates with the pre-mRNA, the spliceosome moiety cleaves or splices the pre-mRNA at the target sequence.

34. The engineered polynucleotide according to any one of claims 1 or 3, wherein the recruitment moiety comprises a sequence complementary to at least 4 nucleotides of the stem-loop II (SL2) sequence of U1 snRNA and / or a sequence comprising phosphorothioate nucleotide linkages that bind to the zinc finger of the U1-C protein.

35. An engineered polynucleotide comprising a nucleotide sequence that is at least 70%, 80%, 85%, or 90% identical or complementary to any one of SEQ ID NOs: 1-8.

36. A method for modifying pre-messenger ribonucleic acid (pre-mRNA) in a cell, the method comprising contacting the cell with the engineered polynucleotide according to any one of claims 1 or 3, wherein the recruitment moiety recruits a post-transcriptional regulatory moiety (e.g., a spliceosome moiety) within the vicinity of the target sequence of the pre-mRNA to modify the pre-mRNA in the cell, thereby resulting in one or more modified pre-mRNAs.

37. The method according to claim 36, wherein the pre-mRNA is encoded by a target gene.

38. The method according to claim 37, wherein the target gene comprises microtubule-associated protein tau (MAPT).

39. The method according to claim 36, wherein the expression or activity of the target gene is modified.

40. The method according to claim 36, wherein prior to the contacting step, the cell exhibits an abnormal messenger ribonucleic acid (mRNA) or protein corresponding to the target gene.

41. A set of engineered polynucleotides, each independently comprising: (i) one or more targeting moieties configured to bind to pre-messenger ribonucleic acid (pre-mRNA) at a target sequence; and (ii) a mobilizing moiety configured to recruit a post-transcriptional regulatory moiety (e.g., a spliceosome moiety), wherein the set of engineered polynucleotides is configured to specifically bind to the pre-mRNA at a plurality of target sequences including the target sequence.

42. An engineered polynucleotide, (a) a first targeting moiety configured to specifically bind to pre-messenger ribonucleic acid (pre-mRNA) at a first target sequence therein, the first targeting moiety comprising a sequence identical or complementary to 5'-GTCCA-3'; (b) a mobilizing moiety comprising a sequence at least 90% similar or complementary to SEQ ID NO: 1 and configured to recruit a spliceosome moiety comprising U1 snRNA and U1-C protein; (c) a second targeting moiety configured to specifically bind to the pre-mRNA at a second target sequence therein, the second targeting moiety comprising a sequence identical or complementary to 5'-CG-3'; wherein the mobilizing moiety comprises a top loop, an upper stem adjacent to the top loop, a lower stem, and an internal loop located between the upper stem and the lower stem; An engineered polynucleotide.

43. Use of the engineered polynucleotide according to any one of claims 1, 3, or 39 in the manufacture of a medicament for treating a disease.

44. Use according to claim 40, wherein the disease is a neurodegenerative disorder.

45. A pharmaceutical composition comprising the engineered polynucleotide according to any one of claims 1, 3, or 39, the pharmaceutical composition comprising a formulation suitable for administration by oral administration, intraperitoneal injection, intravenous administration, subcutaneous injection, intramuscular injection, intradermal injection, transdermal injection, transdermal administration, intranasal administration, intralymphatic injection, rectal administration, or intragastric administration.

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