SYSTEM AND METHOD FOR GENOMEDITATION

Description

Technical field

[0001] The invention relates to the field of genetic engineering. In particular, the present invention relates to a genome editing system for site-directed modification of a target sequence in the genome of a cell, comprising at least one of the following i) to v): i) a Cpfl protein, and a guide RNA; ii) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and a guide RNA; iii) a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; iv) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; v) an expression construct comprising a nucleotide sequence encoding a Cpfl protein and a nucleotide sequence encoding a guide RNA; wherein the Cpfl protein comprises an amino acid sequence of SEQ ID NO: 4, 9 or 10, the guide RNA capable of targeting the Cpfl protein to a target sequence in the genome of the cell. The present invention further relates to said genome editing system for use in treating a disease in a subject in need thereof, wherein the genome editing system is for modifying a gene related with the disease, by introducing said system into a cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence. The present invention also relates to a method of modifying a target sequence in the genome of a plant cell, comprising introducing said genome editing system into the cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence. In addition, the invention relates to a pharmaceutical composition for use in treating a disease in a subject in need thereof, comprising said genome editing system and a pharmaceutically acceptable carrier, wherein the genome editing system is for modifying a gene related with the disease.Background

[0002] The CRISPR (Clustered regular interspaced short palindromic repeats) system is an immune system that is generated during the evolution of bacteria to protect against foreign gene invasion. Among them, the type II CRISPR-Cas9 system is a system for DNA cleavage by a Cas9 protein mediated by two small RNAs (crRNA and tracrRNA) or an artificially synthetized small RNA (sgRNA), and is the simplest one of the three first discovered (Type I, II, III) CRISPR systems. Due to its ease of operation, the system was successfully engineered in 2013 and successfully achieved eukaryotic genome editing. The CRISPR / Cas9 system quickly became the most popular technology in life sciences.

[0003] In 2015, Zhang et al. discovered a new gene editing system through sequence alignment and systematic analysis, the CRISPR-Cpfl system, which is different from the CRISPR-Cas9 system. The system requires only one small RNA (crRNA) to mediate genome editing. There are thousands of CRISPR systems in nature, but only a few can successfully implement eukaryotic genome editing.

[0004] There is still a need in the art for a CRISPR-Cpfl system that enables efficient eukaryotic genome editing.Summary of the Invention

[0005] The invention is defined by the features of the independent claims.

[0006] In one aspect, the present invention provides a genome editing system for site-directed modification of a target sequence in the genome of a cell, comprising at least one of the following i) to v): i) a Cpfl protein, and a guide RNA; ii) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and a guide RNA; iii) a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; iv) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; v) an expression construct comprising a nucleotide sequence encoding a Cpfl protein and a nucleotide sequence encoding a guide RNA; wherein the Cpfl protein comprises an amino acid sequence of SEQ ID NO: 4, 9 or 10, the guide RNA capable of targeting the Cpfl protein to a target sequence in the genome of the cell.

[0007] In a second aspect, the present invention provides a method of modifying a target sequence in the genome of a plant cell, comprising introducing the genome editing system of the invention into the cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in substitution, deletion and / or addition of one or more nucleotides in the target sequence.

[0008] In a third aspect, the invention provides said genome editing system for use in treating a disease in a subject in need thereof, wherein the genome editing system is for modifying a gene related with the disease, by introducing said system into a cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence.

[0009] In a fourth aspect, the invention provides a pharmaceutical composition for use in treating a disease in a subject in need thereof, comprising the genome editing system of the invention and a pharmaceutically acceptable carrier, wherein the genome editing system is for modifying a gene related with the disease.

[0010] In a fifth aspect, the invention provides a crRNA, which comprises a crRNA scaffold sequence corresponding to any one of SEQ ID NOs: 25-33 or the coding sequence of which comprises a sequence set forth in any one of SEQ ID NOs: 25-33.Description of the drawings

[0011] Figure 1. Alignment of direct repeat sequences (DR) from 25 new Cpfl family proteins. The stem duplexes of the 21 mature crRNAs with DR sequences are extremely conserved. Figure 2. Immunofluorescence showing that the Cpfl proteins were localized in the nucleus. Figure 3. shows the ability of the Cpfl proteins to edit human Dnmtl site 3. A: T7EI assay shows that 8 of the 9 selected Cpfl proteins were able to achieve insertion / deletion (indel) at human Dnmtl site 3 in 293T cells; B: sequencing results show representative indel in human Dnmt1 site 3. Figure 4. shows the ability of the Cpfl proteins to edit human Dnmtl site 1. A: The T7EI assay shows that four Cpfl proteins were clearly targeted to human Dnmtl site 1. B: Sequencing results show representative indels in human Dnmtl site 1, wherein 6 Cpfl proteins were capable of producing indels, although PsCpfl and SaCpfl had no significant bands in the enzyme digestion assay. Figure 5. shows the ability of the Cpfl proteins to edit human Dnmtl site 2. A: The T7EI assay shows that four Cpfl proteins were clearly targeted to human Dnmtl site 2. B: Sequencing results show representative indels in human Dnmtl site 2, wherein 5 Cpfl were capable of producing indels, although PsCpfl had no significant bands in the enzyme digestion assay. Figure 6. In vitro assay of PAM sequences of BsCpfl. A: E. coli expression and purification of BsCpfl protein. B-E: Targeting BsCpfl using 5'-TTN PAM. Figure 7. In vitro assay of PAM sequences of each Cpfl. "+" indicates in vitro digestion activity. Figure 8. shows the ability of HkCpfl to edit 8 sites of the human AAVS1 gene. A: The results of T7EI assay. B: Sequencing results show that HkCpfl was able to generate mutations at seven sites, and the PAM sequence is 5'-YYN, which is consistent with the results in Figure 7. Figures 9, 10 and 11 show that the four Cpfl proteins edited the mouse genome in EpiSC cells. Figure 12. Further validation of the editing ability of ArCpfl, BsCpfl, HkCpfl, LpCpfl, PrCpfl and PxCpfl for different targets in mice. Figures 13-14 illustrate the optimization of the crRNA scaffold sequence. Figure 15. shows the various vector maps as used. Detailed Description of the Invention 1. Definition

[0012] In the present invention, the scientific and technical terms used herein have the meaning as commonly understood by a person skilled in the art unless otherwise specified. Also, the protein and nucleic acid chemistry, molecular biology, cell and tissue culture, microbiology, immunology related terms, and laboratory procedures used herein are terms and routine steps that are widely used in the corresponding field. For example, standard recombinant DNA and molecular cloning techniques used in the present invention are well known to those skilled in the art and are more fully described in the following document: Sambrook, J., Fritsch, E.F. and Maniatis, T., Molecular Cloning: A Laboratory Manual; Cold Spring Harbor Laboratory Press: Cold Spring Harbor, 1989 (hereinafter referred to as "Sambrook"). In the meantime, in order to better understand the present invention, definitions and explanations of related terms are provided below.

[0013] "Cpfl nuclease", "Cpfl protein" and "Cpfl" are used interchangeably herein and refer to an RNA-directed nuclease comprising a Cpfl protein or a fragment thereof. Cpfl is a component of the CRISPR-Cpfl genome editing system that targets and cleaves DNA target sequences to form DNA double-strand breaks (DSBs) under the guidance of a guide RNA (crRNA). DSB can activate the intrinsic repair mechanism in the living cell, non-homologous end joining (NHEJ) and homologous recombination (HR), to repair DNA damage in the cell, during which site-directed editing is achieved to the specific DNA sequence.

[0014] "guide RNA" and "gRNA" can be used interchangeably herein. The guide RNA of the CRISPR-Cpfl genome editing system is typically composed only of crRNA molecules, wherein the crRNA comprises a sequence that is sufficiently identical to the target sequence to hybridize to the complement of the target sequence and direct the complex (Cpf1+crRNA) to sequence-specifically bind to the target sequence.

[0015] "Genome" as used herein encompasses not only chromosomal DNA present in the nucleus, but also organellar DNA present in the subcellular components (e.g., mitochondria, plastids) of the cell.

[0016] As used herein, "organism" includes any organism that is suitable for genomic editing, eukaryotes are preferred. Examples of organisms include, but are not limited to, mammals such as human, mouse, rat, monkey, dog, pig, sheep, cattle, cat; poultry such as chicken, duck, goose; plants including monocots and dicots such as rice, corn, wheat, sorghum, barley, soybean, peanut, arabidopsis and the like.

[0017] A "genetically modified organism" or "genetically modified cell" includes an organism or a cell which comprises within its genome an exogenous polynucleotide or a modified gene or expression regulatory sequence. For example, the exogenous polynucleotide is stably integrated within the genome of the organism or the cell such that the polynucleotide is passed on to successive generations. The exogenous polynucleotide may be integrated into the genome alone or as part of a recombinant DNA construct. The modified gene or expression regulatory sequence means that, in the organism genome or the cell genome, said sequence comprises one or more nucleotide substitution, deletion, or addition.

[0018] "Exogenous" in reference to a sequence means a sequence from a foreign species, or refers to a sequence in which significant changes in composition and / or locus occur from its native form through deliberate human intervention if from the same species.

[0019] "Polynucleotide", "nucleic acid sequence", "nucleotide sequence" or "nucleic acid fragment" are used interchangeably and are single-stranded or double-stranded RNA or DNA polymers, optionally containing synthetic, non-natural or altered nucleotide bases. Nucleotides are referred to by their single letter names as follows: "A" is adenosine or deoxyadenosine (corresponding to RNA or DNA, respectively), "C" means cytidine or deoxycytidine, "G" means guanosine or deoxyguanosine, "U" represents uridine, "T" means deoxythymidine, "R" means purine (A or G), "Y" means pyrimidine (C or T), "K" means G or T, "H" means A or C or T, "I" means inosine, and "N" means any nucleotide.

[0020] "Polypeptide," "peptide," and "protein" are used interchangeably in the present invention to refer to a polymer of amino acid residues. The terms apply to an amino acid polymer in which one or more amino acid residues is artificial chemical analogue of corresponding naturally occurring amino acid(s), as well as to a naturally occurring amino acid polymer. The terms "polypeptide," "peptide," "amino acid sequence," and "protein" may also include modified forms including, but not limited to, glycosylation, lipid ligation, sulfation, γ carboxylation of glutamic acid residues, and ADP-ribosylation.

[0021] Sequence "identity" has recognized meaning in the art, and the percentage of sequence identity between two nucleic acids or polypeptide molecules or regions can be calculated using the disclosed techniques. Sequence identity can be measured along the entire length of a polynucleotide or polypeptide or along a region of the molecule. (See, for example, Computational Molecular Biology, Lesk, A.M., ed., Oxford University Press, New York, 1988; Biocomputing: Informatics and Genome Projects, Smith, D.W., ed., Academic Press, New York, 1993; Computer Analysis of Sequence Data, Part I, Griffin, A.M., and Griffin, H.G., eds., Humana Press, New Jersey, 1994; Sequence Analysis in Molecular Biology, von Heinje, G., Academic Press, 1987; and Sequence Analysis Primer, Gribskov, M. and Devereux, J., eds., M Stockton Press, New York, 1991). Although there are many methods for measuring the identity between two polynucleotides or polypeptides, the term "identity" is well known to the skilled person (Carrillo, H. & Lipman, D., SIAM J Applied Math 48: 1073 (1988)).

[0022] Suitable conserved amino acid replacements in peptides or proteins are known to those skilled in the art and can generally be carried out without altering the biological activity of the resulting molecule. In general, one skilled in the art recognizes that a single amino acid replacement in a non-essential region of a polypeptide does not substantially alter biological activity (See, for example, Watson et al., Molecular Biology of the Gene, 4th Edition, 1987, The Benjamin / Cummings Pub. co., p.224).

[0023] As used in the present invention, "expression construct" refers to a vector such as a recombinant vector that is suitable for expression of a nucleotide sequence of interest in an organism. "Expression" refers to the production of a functional product. For example, expression of a nucleotide sequence may refer to the transcription of a nucleotide sequence (e.g., transcription to produce mRNA or functional RNA) and / or the translation of an RNA into a precursor or mature protein.

[0024] The "expression construct" of the present invention may be a linear nucleic acid fragment, a circular plasmid, a viral vector or, in some embodiments, an RNA that is capable of translation (such as mRNA).

[0025] The "expression construct" of the present invention may comprise regulatory sequences and nucleotide sequences of interest from different origins, or regulatory sequences and nucleotide sequences of interest from the same source but arranged in a manner different from that normally occurring in nature.

[0026] "Regulatory sequence" and "regulatory element" are used interchangeably to refer to a nucleotide sequence that is located upstream (5 'non-coding sequence), middle or downstream (3' non-coding sequence) of a coding sequence and affects the transcription, RNA processing or stability or translation of the relevant coding sequence. Regulatory sequences may include, but are not limited to, promoters, translation leaders, introns and polyadenylation recognition sequences.

[0027] "Promoter" refers to a nucleic acid fragment capable of controlling the transcription of another nucleic acid fragment. In some embodiments of the present invention, the promoter is a promoter capable of controlling the transcription of a gene in a cell, whether or not it is derived from the cell. The promoter may be a constitutive promoter or tissue-specific promoter or developmentally-regulated promoter or inducible promoter.

[0028] "Constitutive promoter" refers to a promoter that may in general cause the gene to be expressed in most cases in most cell types. "Tissue-specific promoter" and "tissue-preferred promoter" are used interchangeably and mean that they are expressed primarily but not necessarily exclusively in one tissue or organ, but also in a specific cell or cell type. "Developmentally-regulated promoter" refers to a promoter whose activity is dictated by developmental events. "Inducible promoter" selectively express operably linked DNA sequences in response to an endogenous or exogenous stimulus (environment, hormones, chemical signals, etc.).

[0029] As used herein, the term "operably linked" refers to the linkage of a regulatory element (e.g., but not limited to, a promoter sequence, a transcription termination sequence, etc.) to a nucleic acid sequence (e.g., a coding sequence or an open reading frame) such that transcription of the nucleotide sequence is controlled and regulated by the transcriptional regulatory element. Techniques for operably linking regulatory element regions to nucleic acid molecules are known in the art.

[0030] "Introduction" of a nucleic acid molecule (e.g., plasmid, linear nucleic acid fragment, RNA, etc.) or protein into an organism means that the nucleic acid or protein is used to transform an organism cell such that the nucleic acid or protein is capable of functioning in the cell. As used in the present invention, "transformation" includes both stable and transient transformations.

[0031] "Stable transformation" refers to the introduction of exogenous nucleotide sequences into the genome, resulting in the stable inheritance of foreign genes. Once stably transformed, the exogenous nucleic acid sequence is stably integrated into the genome of the organism and any of its successive generations.

[0032] "Transient transformation" refers to the introduction of a nucleic acid molecule or protein into a cell, performing a function without the stable inheritance of an exogenous gene. In transient transformation, the exogenous nucleic acid sequences are not integrated into the genome.2. Efficient genome editing system

[0033] Disclosed herein, but not part of the invention is the use of the Cpfl protein comprising amino acid sequences having at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, even 100% sequence identity to one of SEQ ID NOs: 1-12 in eukaryotic genome editing.

[0034] In one aspect, the present invention provides a genome editing system for site-directed modification of a target sequence in the genome of a cell, comprising at least one of the following i) to v): i) a Cpfl protein, and a guide RNA; ii) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and a guide RNA; iii) a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; iv) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; v) an expression construct comprising a nucleotide sequence encoding a Cpfl protein and a nucleotide sequence encoding a guide RNA; wherein the Cpfl protein comprises an amino acid sequence of SEQ ID NO: 4, 9 or 10, the guide RNA capable of targeting the Cpfl protein to a target sequence in the genome of the cell.

[0035] In some embodiments of the methods of the invention, the guide RNA is a crRNA. In some embodiments, the coding sequence of the crRNA comprises a crRNA scaffold sequence set forth in any one of SEQ ID NOs: 25-33. In some preferred embodiments, the crRNA scaffold sequence is SEQ ID NO:30. In some embodiments, the coding sequence of the cRNA further comprises a sequence that specifically hybridizes to the complement of the target sequence (i.e., a spacer sequence) at 3' of the cRNA scaffold sequence.

[0036] In some embodiments, the crRNA is encoded by a nucleotide sequence selected from the group consisting of: i) 5'-ATTTCTACtgttGTAGAT(SEQ ID NO:25)-N x -3'; ii) 5'- ATTTCTACtattGTAGAT(SEQ ID NO:26)-N x -3'; iii) 5'- ATTTCTACtactGTAGAT(SEQ ID NO:27)-N x -3'; iv) 5'- ATTTCTACtttgGTAGAT(SEQ ID NO:28)-N x -3'; v) 5'- ATTTCTACtagttGTAGAT(SEQ ID NO:29)-N x -3'; vi) 5'- ATTTCTACTATGGTAGAT(SEQ ID NO:30)-N x -3'; vii) 5'- ATTTCTACTGTCGTAGAT(SEQ ID NO:31)-N x -3'; viii) 5'- ATTTCTACTTGTGTAGAT(SEQ ID NO:32)-N x -3'; and ix) 5'- ATTTCTACTGTGGTAGAT(SEQ ID NO:33)-N x -3', wherein Nx represents nucleotide sequence that consists of x consecutive nucleotides, N is independently selected from A, G, C and T; x is an integer of 18 ≤ x ≤ 35, preferably, x=23. In some embodiments, the sequence Nx (spacer sequence) is capable of specifically hybridizing to the complement of the target sequence.

[0037] In some embodiments of the methods of the invention, the cell is a eukaryotic cell, preferably a mammalian cell.

[0038] Disclosed herein, but not part of the invention is the Cpfl protein comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97% of at least 98%, at least 99%, or even 100% sequence identity to one of SEQ ID NOs: 1-12. The Cpfl protein is capable of targeting and / or cleaving target sequences in the genome of the cell through a crRNA.

[0039] Disclosed herein, but not part of the invention is the Cpfl protein comprising an amino acid sequence having one or more amino acid residue substitution, deletion or addition relative to one of SEQ ID NOs: 1-12. For example, the Cpfl protein comprises an amino acid sequence having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 amino acid residues substitution, deletion or addition relative to one of SEQ ID NOs: 1-12. Disclosed herein, but not part of the invention is that the amino acid substitution is a conservative substitution. The Cpfl protein is capable of targeting and / or cleaving target sequences in the cell genome through a crRNA.

[0040] The Cpfl protein of the invention may be derived from a species selected from: Helcococcus kunzii, Proteocatella sphenisci, or Candidatus Dojkabacteria.

[0041] Disclosed herein, but not part of the invention is the Cpfl protein being derived from Agathobacter rectalis (ArCpfl), Butyrivibrio sp. (BsCpfl), Lachnospira pectinoschiza (LpCpfl), Pseudobutyrivibrio ruminis (PrCpfl) or Pseudobutyrivibrio xylanivorans (PxCpfl). As disclosed herein, the Cpfl protein comprises an amino acid sequence selected from SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 8, SEQ ID NO: 11, SEQ ID NO : 12.

[0042] Disclosed herein, but not part of the invention is that the Cpfl protein of the present invention further comprises a nuclear localization sequence (NLS). In general, one or more NLSs in the Cpfl protein should have sufficient strength to drive the Cpfl protein in the nucleus of the cell to accumulate to an amount for achieving genome editing. In general, the intensity of nuclear localization activity is determined by the number, location of the NLS, one or more specific NLSs used in the Cpfl protein, or a combination of these factors.

[0043] Disclosed herein, but not part of the invention is that the NLS of the Cpfl protein of the present invention may be located at the N-terminus and / or C-terminus. Disclosed herein, but not part of the invention is that the Cpfl protein comprises about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more NLSs. Disclosed herein, but not part of the invention is that the Cpfl protein comprises about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more NLS at or near the N-terminus. Disclosed herein, but not part of the invention is that the Cpfl protein comprises about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more NLSs at or near the C-terminus. Disclosed herein, but not part of the invention is that the Cpfl protein comprises a combination of these, such as comprises one or more NLSs at the N-terminus and one or more NLSs at the C-terminus. When there is more than one NLS, each can be selected to be independent of other NLSs. Disclosed herein, but not part of the invention is that the Cpfl protein comprises two NLSs, for example, the two NLSs are located at the N-terminus and the C-terminus, respectively.

[0044] In general, NLS consists of one or more short sequences of positively charged lysine or arginine exposed on the surface of the protein, but other types of NLS are also known. Non-limiting examples of NLS include: KKRKV (nucleotide sequence 5'-AAGAAGAGAAAGGTC-3'), PKKKRKV (nucleotide sequence 5'-CCCAAGAAGAAGAGGAAGGTG-3' or CCAAAGAAGAAGAGGAAGGTT), or SGGSPKKKRKV (nucleotide sequence 5'- TCGGGGGGGAGCCCAAAGAAGAAGCGGAAGGTG -3').

[0045] Furthermore, depending on the location of the DNA to be edited, the Cpfl proteins may also include other localization sequences, such as cytoplasm localization sequences, chloroplast localization sequences, mitochondrial localization sequences, and the like.

[0046] To obtain efficient expression in the target cells, the nucleotide sequence encoding the Cpfl protein may be codon optimized for the organism from which the cell to be genome edited is derived.

[0047] Codon optimization refers to the replacement of at least one codon (e.g., about or more than about 1, 2, 3, 4, 5, 10, 15, 20, 25, 50 or more codons) of a native sequence by a codon that is used more frequently or most frequently in the gene of the host cell, modifying the nucleic acid sequence while maintaining the native amino acid sequence to enhance expression in the host cell of interest. Different species show specific preferences for certain codons of a particular amino acid. Codon preference (difference in codon usage between organisms) is often associated with the efficiency of translation of messenger RNA (mRNA), which is believed to depend on the nature of the translated codon and the availability of specific transfer RNA (tRNA) molecules. The advantages of selected tRNAs within cells generally reflect the most frequently used codons for peptide synthesis. Therefore, genes can be customized to be best gene expressed in a given organism based on codon optimization. The codon usage table can be easily obtained, for example, in the Codon Usage Database available at www.kazusa.orjp / codon / , and these tables can be adjusted in different ways. See, Nakamura Y. et. al "Codon usage tabulated from the international DNA sequence databases: status for the year 2000 Nucl.Acids Res, 28: 292 (2000).

[0048] The organism from which the cell can be edited by the method of the present invention is derived preferably is eukaryote, including but not limited to mammals such as human, mouse, rat, monkey, dog, pig, sheep, cattle, cat; a poultry such as chicken, duck, goose; plants including monocots and dicots, such as rice, corn, wheat, sorghum, barley, soybean, peanut and arabidopsis thaliana and so on.

[0049] Disclosed herein, but not part of the invention is that the nucleotide sequence encoding the Cpfl protein may be codon optimized for human. Disclosed herein, but not part of the invention is that the codon-optimized nucleotide sequence encoding the Cpfl protein may be selected from SEQ ID NOs: 13-24.

[0050] In some embodiments of the present invention, the nucleotide sequence encoding the Cpfl protein and / or the nucleotide sequence encoding the guide RNA is operably linked to an expression regulatory element such as a promoter.

[0051] Examples of promoters that can be used in the present invention include, but are not limited to, the polymerase (pol) I, pol II or pol III promoters. Examples of the pol I promoter include the gallus RNA pol I promoter. Examples of the pol II promoters include, but are not limited to, the immediate-early cytomegalovirus (CMV) promoter, the Rous sarcoma virus long terminal repeat (RSV-LTR) promoter, and the immediate-early simian virus 40 (SV40) promoter. Examples of pol III promoters include the U6 and H1 promoters. An inducible promoter such as a metallothionein promoter can be used. Other examples of promoters include the T7 phage promoter, the T3 phage promoter, the β-galactosidase promoter, and the Sp6 phage promoter, and the like. Promoters that can be used in plants include, but are not limited to, cauliflower mosaic virus 35S promoter, maize Ubi-1 promoter, wheat U6 promoter, rice U3 promoter, maize U3 promoter, rice actin promoter.

[0052] In another aspect, the invention provides a crRNA, comprises a crRNA scaffold sequence corresponding to any one of SEQ ID NOs: 25-33. In some embodiments, the coding sequence of the crRNA comprises the crRNA scaffold sequence set forth in any one of SEQ ID NOs: 25-33. In some preferred embodiments, the crRNA scaffold sequence is SEQ ID NO:30. In some embodiments, the coding sequence of the cRNA further comprises a sequence that specifically hybridizes to the complement of the target sequence (i.e., a spacer sequence) at 3' of the cRNA scaffold sequence.

[0053] In some embodiments, the crRNA is encoded by a nucleotide sequence selected from the group consisting of: i) 5'-ATTTCTACtgttGTAGAT(SEQ ID NO:25)-N x -3'; ii) 5'- ATTTCTACtattGTAGAT(SEQ ID NO:26)-N x -3'; iii) 5'- ATTTCTACtactGTAGAT(SEQ ID NO:27)-N x -3'; iv) 5'- ATTTCTACtttgGTAGAT(SEQ ID NO:28)-N x -3'; v) 5'- ATTTCTACtagttGTAGAT(SEQ ID NO:29)-N x -3'; vi) 5'- ATTTCTACTATGGTAGAT(SEQ ID NO:30)-N x -3'; vii) 5'- ATTTCTACTGTCGTAGAT(SEQ ID NO:31)-N x -3'; viii) 5'- ATTTCTACTTGTGTAGAT(SEQ ID NO:32)-N x- 3'; and ix) 5'- ATTTCTACTGTGGTAGAT(SEQ ID NO:33)-N x -3', wherein Nx represents nucleotide sequence that consists of x consecutive nucleotides, N is independently selected from A, G, C and T; x is an integer of 18 ≤ x ≤ 35, preferably, x=23. In some embodiments, the sequence Nx (spacer sequence) is capable of specifically hybridizing to the complement of the target sequence.

[0054] In some embodiments, the crRNAs of the invention are particularly suitable for use in combination with the Cpfl protein of the invention for genome editing, particularly for genome editing in eukaryotic cells.3. Method for modifying a target sequence in the genome of a cell

[0055] In one aspect, the present invention provides a method of modifying a target sequence in the genome of a plant cell, comprising introducing the genome editing system of the present invention into the cell, whereby the guide RNA targets the Cpfl protein to a target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion and / or addition in the target sequence.

[0056] In another aspect, the present invention provides a method of producing a genetically modified plant cell, comprising introducing the genome editing system of the present invention into the cell, whereby the guide RNA targets the Cpfl protein to a target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion and / or addition in the target sequence.

[0057] Disclosed herein, but not part of the invention is that said method provides a genetically modified organism comprising a genetically modified cell produced by the method of the invention or a progeny cell thereof.

[0058] The design of target sequences or crRNA coding sequences that can be recognized and targeted by the Cpfl protein and guide RNA (i.e., crRNA) complex can be found, for example, in Zhang et al., Cell 163, 1-13, October 22, 2015. In general, the 5'-terminus of the target sequence targeted by the genome editing system of the present invention needs to include a protospacer adjacent motif (PAM) 5'-TTTN, 5'-TTN, 5'-CCN, 5'-TCCN, 5'-TCN or 5'-CTN, wherein N is independently selected from A, G, C and T.

[0059] For example, in some embodiments of the present invention, the target sequence has the following structure: 5'-TYYN-Nx-3' or 5'-YYN-Nx-3', wherein N is independently selected from A, G, C and T, Y is selected from C and T; x is an integer of 15 ≤ x ≤ 35; Nx represents x consecutive nucleotides.

[0060] In some embodiments, the coding sequence of the crRNA comprises a crRNA scaffold sequence set forth in any one of SEQ ID NOs: 25-33. In some preferred embodiments, the crRNA scaffold sequence is SEQ ID NO:30. In some embodiments, the coding sequence of the cRNA further comprises a sequence that specifically hybridizes to the complement of the target sequence (i.e., a spacer sequence) at 3' of the cRNA scaffold sequence.

[0061] In some embodiments, the crRNA is encoded by a nucleotide sequence selected from the group consisting of: i) 5'-ATTTCTACtgttGTAGAT(SEQ ID NO:25)-N x -3'; ii) 5'- ATTTCTACtattGTAGAT(SEQ ID NO:26)-N x -3'; iii) 5'- ATTTCTACtactGTAGAT(SEQ ID NO:27)-N x -3'; iv) 5'- ATTTCTACtttgGTAGAT(SEQ ID NO:28)-N x -3'; v) 5'-ATTTCTACtagttGTAGAT(SEQ ID NO:29)-N x -3'; vi) 5'- ATTTCTACTATGGTAGAT(SEQ ID NO:30)-N x -3'; vii) 5'- ATTTCTACTGTCGTAGAT(SEQ ID NO:31)-N x -3'; viii) 5'- ATTTCTACTTGTGTAGAT(SEQ ID NO:32)-N x -3'; and ix) 5'- ATTTCTACTGTGGTAGAT(SEQ ID NO:33)-N x -3', wherein Nx represents nucleotide sequence that consists of x consecutive nucleotides, N is independently selected from A, G, C and T; x is an integer of 18 ≤ x ≤ 35, preferably, x=23. In some embodiments, the sequence Nx (spacer sequence) is capable of specifically hybridizing to the complement of the target sequence.

[0062] In the present invention, the target sequence to be modified may be located at any location in the genome, for example, in a functional gene such as a protein-encoding gene, or may be, for example, located in a gene expression regulatory region such as a promoter region or an enhancer region, thereby modification of gene functional or modification of gene expression can be achieved.

[0063] The substitution, deletion and / or addition in the target sequence of the cell can be detected by T7EI, PCR / RE or sequencing methods.

[0064] In the method of the present invention, the genome editing system can be introduced into the cell by a variety of methods well known to those skilled in the art.

[0065] Methods that can be used to introduce the genome editing system of the present invention into a cell include, but are not limited to, calcium phosphate transfection, protoplast fusion, electroporation, lipofection, microinjection, viral infection (e.g., baculovirus, vaccinia virus, adenovirus, adeno-associated virus, lentivirus and other viruses), gene gun method, PEG-mediated protoplast transformation, Agrobacterium-mediated transformation.

[0066] A cell edited by said genome editing system for site-directed modification of a target sequence in the genome of a cell can be a cell of mammals such as human, mouse, rat, monkey, dog, pig, sheep, cattle, cat; a cell of poultry such as chicken, duck, goose; a cell of plants including monocots and dicots, such as rice, corn, wheat, sorghum, barley, soybean, peanut and Arabidopsis thaliana and so on.

[0067] In some embodiments, said genome editing system for site-directed modification of a target sequence in the genome of a cell may be employed for use in vitro. For example, the cell is an isolated cell. In some embodiments, the cell is a CAR-T cell. In some embodiments, the cell is an induced embryonic stem cell.

[0068] In other embodiments, said genome editing system for site-directed modification of a target sequence in the genome of a cell may be employed for use in vivo. For example, the cell is a cell within an organism, and the system of the present invention can be introduced into the cell in vivo. For example, the cell can be a tumor cell in a patient.4. Therapeutic applications

[0069] The invention also encompasses said genome editing system as described for use in treating a disease in a subject in need thereof, wherein the genome editing system is for modifying a gene related with the disease, by introducing said system into a cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence.

[0070] By modifying a disease-related gene by the genome editing system of the present invention, it is possible to achieve up-regulation, down-regulation, inactivation, activation, or mutation correction of the disease-related gene, thereby achieving disease prevention and / or treatment. For example, the target sequence may be located in a protein coding region of the disease-related gene, or may be, for example, located in a gene expression regulatory region such as a promoter region or an enhancer region, thereby enabling functional modification of the disease-related gene or expression modification of the disease-related gene.

[0071] A "disease-related" gene refers to any gene that produces a transcriptional or translational product at an abnormal level or in an abnormal form in a cell derived from a disease-affected tissue as compared to a non-disease control tissue or cell. When altered expression is related with the appearance and / or progression of a disease, it may be a gene that is expressed at an abnormally high level; or it may be a gene that is expressed at an abnormally low level. A disease-related gene also refers to a gene having one or more mutations or a genetic variation that is directly responsible for the disease or is genetic linkage with one or more genes responsible for the etiology of the disease. The transcribed or translated product may be known or unknown, and may be at normal or abnormal levels.

[0072] The invention also provides a pharmaceutical composition for use in treating a disease in a subject in need thereof, comprising the genome editing system of the invention and a pharmaceutically acceptable carrier, wherein the genome editing system is for modifying a gene related with the disease.

[0073] In some embodiments, the subject is a mammal, such as a human.

[0074] Examples of such diseases include, but are not limited to, tumors, inflammation, Parkinson's disease, cardiovascular disease, Alzheimer's disease, autism, drug addiction, age-related macular degeneration, schizophrenia, hereditary diseases, and the like.

[0075] Further examples of diseases and corresponding disease-related genes according to the invention can be found, for example, from Chinese patent application CN201480045703.4.5. Kit

[0076] Disclosed herein, but not part of the invention is a kit, comprising the genome editing system of the invention, and an instruction. The kit generally includes a label indicating the intended use and / or method for use of the contents of the kit. The term label includes any written or recorded material provided on or with the kit or otherwise provided with the kit.Example Material and Method Cell culture and transfection

[0077] HEK293T, HeLa cells were cultured in DMEM medium (Gibco) supplemented with 10% FBS (Gibco) and 100 U / ml penicillin and 100 ug / ml streptomycin, and mouse EpiSC cells were cultured in N2B27 medium supplemented with bFGF. 12 h before transfection, the cells were seeded in a 12-well plate at the density of 500,000 per well. After 12 h, the density of the cells was about 60%-70%, and then 1.5 ug (Cpfl: crRNA = 2:1) plasmid was transfected into the cells using Lipofectamine LTX and PLUS reagents (Invitrogen), and the medium was replaced with serum-free opti-MEM medium (Gibco) before transfection. After transfection, it was replaced with serum-added DMED medium at 8-12 h after transfection. 48 h after transfection, GFP positive cells were sorted by FACS for genotyping.Genotype analysis: T7EI analysis and DNA sequencing

[0078] GFP-positive cells were sorted by FACS, lysed with Buffer L+1 / 100V Protease K (Biotool) at 55 °C for 30 min, inactivated at 95 °C for 5 min, and directly used for PCR detection. Appropriate primers were designed near the Cpfl targeting site, and the amplified product was purified using DNA Clean & ConcentratorTM-5 kit (ZYMO Research). 200 ng of purified PCR product was added into 1 uL of NEBuffer2 (NEB) and diluted to 10 uL with ddH 2 O. Then, heterodimers were formed by re-annealing according to the previously reported method (Li, W., et al., Simultaneous generation and germline transmission of multiple gene mutations in rat using CRISPR-Cas systems. Nat Biotechnol, 2013. 31(8): p. 684-6). The reannealed product was added with 0.3 uL of T7EI endnucelease and 1 / 10 V NEBuffer2 (NEB), and digested at 37 °C for 1h 30min. Genotype analysis was performed by 3% TAE-Gel electrophoresis. Indels were calculated according to the method reported in the previous article (Cong, L., et al., Multiplex genome engineering using CRISPR / Cas systems. Science, 2013. 339(6121): p. 819-23).

[0079] The PCR product corresponding to the T7EI positive sample was ligated to the pEASY-T1 or pEASY-B (Transgen) vector, then transformed, plated, and incubated at 37 °C overnight. An appropriate amount of single colonies were picked for Sanger sequencing. Genotypes of mutants were determined by alignment with genotype of the wild-type.Immunofluorescence staining

[0080] The Cpfl eukaryotic expression vector was transfected into HeLa cells for 48 hours and then fixed with 4% PFA for 10 min at room temperature; washed three times with PBST (PBS + 0.3% Triton X100), blocked with 2% BSA (+ 0.3% Triton X100) for 15 min at room temperature, incubated with primary antibody Rat anti-HA (Roche, 1:1000) overnight, washed three times with PBST, and incubated with Cy3-labeled fluorescent secondary antibody (Jackson ImmunoResearch, 1:1000) for 2 h at room temperature. Nucleus were stained with DAPI (Sigma, 1: 1000) for 10 min, and washed three times with PBST. The slides were mounted with Aqueous Mounting Medium (Abeam) and fixed. Zeiss LSM780 was used for observation.Prokaryotic expression and purification of Cpfl protein

[0081] The Cpfl encoding gene was cloned into the prokaryotic expression vector BPK2103 / 2104. The 10xHis tag fused on C-terminal was used to purify the protein. The expression vector was transformed into BL21 (DE3) E. coli competent cells (Transgen). Clones in which IPTG induced high expression were selected and inoculated into 300 mL of CmR+ LB medium, cultured at 37 °C with shaking to OD600~0.4. IPTG was added at a final concentration of 1 mM to induce expression at 16 °C for 16 h. The culture was centrifuged at 8000 rpm at 4 °C for 10 min, and the bacterial pellet was collected. The bacteria were lysed in 40 mL NPI-10 (+1× EDTA-free Protease Inhibitor Cocktail, Roche; + 5% glycerol) on ice bath with ultrasonication crushing: total time 15 min, ultrasonication 2 s, pause 5s, at the power of 100W. After crushing, centrifugation was performed at 8000 rpm at 4 °C for 10 min, and the supernatant was collected. 2 mL of His60 Ni Superflow Resin (Takara) was added to the supernatant, shaked at 4 °C for 1 h, purified by Polypropylene Colums (Qiagen). Using gravity flow, the undesired proteins without the fused His10 tag was thoroughly washed away with 20 mL of NPI-20, 20 mL of NPI-40 and 10 mL of NPI-100, respectively. Finally, the Cpfl protein with fused His10 tag was eluted from the Ni column with 6 × 0.5 mL NPI-500. The eluted protein of interest was dialyzed overnight against a dialysate (50 mM Tris-HCl, 300 mM KCl, 1 mM DTT, 20% Glycerol). The protein solution after dialysis was concentrated with 100 kDa Amicon Ultra-4, PLHK Ultracel-PL ultrafiltration tube (Millipore). Protein concentration was determined using a Micro BCATM Protein Assay Kit (Thermo ScientificTM).RNA in vitro transcription

[0082] An in vitro transcriptional crRNA template with a T7 promoter was synthesized (BGI) and the crRNA was transcribed in vitro using the HiScribe ™< T7 Quick High Yield RNA Synthesis Kit (NEB) according to the protocol. After the transcription was completed, crRNA was purified by Oligo Clean & Concentrator ™< (ZYMO Research), and measured with NanoDrop (Thermo Scientific ™< ) for the concentration, and stored at -80 °C.In vitro digestion analysis

[0083] The target sequences with different 5'PAM sequences were synthesized and cloned into pUC19 or p11-LacY-wtx1 vector, amplified with primers and purified. 200 ng of purified PCR product was reacted with 400 ng of crRNA and 50 nM of Cpfl protein in NEBUffer3 (NEB) reaction system for 1 h at 37 °C, respectively. It was then analyzed by electrophoresis on a 12% Urea-TBE-PAGE gel or 2.5% agarose gel.Target sequence

[0084] The target sequences used in the experiment are shown in Table 1 below: Table 1TargetSequence(5'-3')5'PAM (5'-3')Human Dnmt1 Target site 1CCTCACTCCTGCTCGGTGAATTTTTTCHuman Dnmt1 Target site 2AGGAGTGTTCAGTCTCCGTGAACTTTGHuman Dnmt1 Target site 3CTGATGGTCCATGTCTGTTACTCTTTCMouse MeCP2 Target site 1CCTGCCTCTGCTGGCTCTGCAGATTTGMouse MeCP2 Target site 2TGATGTTTCTGCTTTGCCTGCCTTTTCMouse MeCP2 Target site 3GGGGAAGCCGAGGCTTCTGGCACTTTGMouse MeCP2 Target site 4GTGTCCAACCTTCAGGCAAGGTGTTTCMouse MeCP2 Target site 5GCCTGCCTCTGCTGGCTCTGCAGTTTMouse MeCP2 Target site 6CTGATGTTTCTGCTTTGCCTGCCTTTMouse MeCP2 Target site 7GGGGGAAGCCGAGGCTTCTGGCATTTMouse MeCP2 Target site 8CGTGTCCAACCTTCAGGCAAGGTTTTMouse Tet1 Target site 1TCGGGTCAGCATCACTGGCTCAGTTTCMouse Tet1 Target site 2CTGGGAGCAGCCTGAGAACCCTGTTTGMouse Tet1 Target site 3ACATCAGCTGAGCCAGTGATGCTTTTGMouse Tet1 Target site 4GATTCTTGCAGTAGGTGCACTCCTTTCMouse Tet1 Target site 5CTCTTCTTACAGATCTGGTGGCTTTTCMouse Tet1 Target site 6CTCGGGTCAGCATCACTGGCTCATTTMouse Tet1 Target site 7CACAGGCCAGTACCTCTTCTCCCTTAMouse Tet1 Target site 8CGATTCTTGCAGTAGGTGCACTCTTTHuman AAVS 1 Target site 1TGAGAATGGTGCGTCCTAGGTGTTTTGHuman AAVS 1 Target site 2GTGAGAATGGTGCGTCCTAGGTGTTTHuman AAVS 1 Target site 3ACCAGGTCGTGGCCGCCTCTACTTTCHuman AAVS 1 Target site 4TGTGGAAAACTCCCTTTGTGAGACCGHuman AAVS 1 Target site 5CTACTCCCTTTCTCTTTCTCCATCCTHuman AAVS 1 Target site 6TGTCCCCCTTCCTCGTCCACCATCCCHuman AAVS 1 Target site 7CCTTTGTGAGAATGGTGCGTCCTCTCHuman AAVS 1 Target site 8CTACAGGGGTTCCTGGCTCTGCTTCCMouse Apob Target site 12GTGGGCCCATGGCGGATGGATGGTTTCMouse Nrl Target site 1CCTCCCAGTCCCTTGGCTATGGATTTCMouse Nrl Target site 7GGCTCCACACCATACAGCTCGGTTTG Example 1. Identification of novel Cpfl proteins

[0085] CRISPR / Cpf1 (Clustered Regularly Interspaced Short Palindromic Repeats from Prevotella and Francisella 1) is an acquired immune mechanism found in Prevotella and Francisella and successfully engineered for DNA editing (Zetsche, B., et al., Cpfl is a single RNA-guided endonuclease of a class 2 CRISPR-Cas system. Cell, 2015. 163(3): p. 759-71.). Unlike CRISPR / Cas9, Cpfl requires only one crRNA as a guide, no tracrRNA is required, and the Cpfl protein uses a T-rich PAM sequence.

[0086] The present inventors performed a PSI-Blast search in the NCBI database using the already reported AsCpf1, LbCpf1 and FnCpf1, and selected 25 unreported Cpfl proteins, of which 21 Cpfl proteins possess a direct repeat (DR) sequence.

[0087] By sequence alignment, the sequences and the RNA secondary structures of the 21 DR from different Cpfl proteins were found to be quite conserved (Fig. 1). Based on the hypothesis that besides the conserved crRNA, the PAM sequences of all Cpfl proteins were also conserved (i.e., all using T-rich PAM sequences), 12 of the 25 Cpfl proteins were selected as candidates. The specific information of the selected 12 candidate Cpfl proteins is shown in Table 2 below: Table 2. Candidate Cpfl ProteinsNameBacteria SourceGenBank IDAmino Acid Sequence (SEQ ID NO)Codon optimization (human) nucleotide sequence (SEQ ID NO)ArCpf1Agathobacter rectalis strain 2789STDY5834884CZAJ0100000 1.1113LpCpf1Lachnospira pectinoschiza strain 2789STDY5834886CZAK010000 04.1214SaCpf1Sneathia amnii strain SN3CP011280.1315HkCpf1Helcococcus kunzii ATCC 51366JH601088.1 / AGEI0100002 2.1416AbCpf1Arcobacter butzleri L348JAIQ0100003 9.1517BoCpf1Bacteroidetes oral taxon 274NZ_GG774890.1618OsCpf1Oribacterium sp. NK2B42NZ_KE38419 0.1719BsCpflButyrivibrio sp. NC30NZ_AUKC01 000013.1820PsCpflProteocatella sphenisci DSM 23131NZ_KE38402 8.1921C6Cpf1Candidatus DojkabacteriaLBTH010000 07.11022PxCpflPseudobutyrivibrio xylanivorans strain DSM 10317FMWK01000 002.11123PrCpflPseudobutyrivibrio ruminisNZ_KE38412 1.11224 Example 2. Verification of the ability of the Cpfl proteins to edit human genome

[0088] Codon optimization was performed for expression in humans and 12 selected protein coding sequences were synthesized (BGI), cloned into eukaryotic expression vectors (pCAG-2AeGFP-SV40 and pCAG-2AeGFP-SV40_v4) and prokaryotic expression vectors (BPK2103-ccdB and BPK2014-ccdB).

[0089] Through HeLa cell transfection experiments, we can find that the selected Cpfl proteins can be clearly expressed in the nucleus (Fig. 2).

[0090] Next, by co-transfection with crRNA targeting human Dnmt1 gene into 293T cells and identification by PCR and T7EI digestion, 8 Cpfl proteins (Ab, Ar, Bo, Bs, Hk, Lp, Ps, Sa) were found to induce mutation at site 3 of the Dnmt1 gene in 293T cells (Fig. 3A). DNA sequencing further confirmed that the gene site did produce a genetic mutation (Fig. 3B).

[0091] To further demonstrate that the identified Cpfl proteins can induce mutations in the mammalian genome, the above experiments were repeated using sites 1 and 2 of the Dnmt1 gene. T7EI digestion results revealed that four proteins, ArCpfl, BsCpfl, HkCpfl and LpCpfl, produced significant indels at both sites (Figs. 4A and 5A). DNA sequencing results showed that besides the above four proteins, PsCpfl and SaCpfl also caused mutations in the gene (Figs. 4B and 5B).Example 3. Identification of PAM sequences

[0092] To determine the PAM sequence of the identified Cpfl proteins, first, the BsCpfl protein was selected for detailed study.

[0093] BsCpfl was expressed in E. coli and purified by His tag (Fig. 6A). The purified BsCpfl protein and the corresponding crRNA and dsDNA fragment (human Dnmt1 target site 2) were incubated at 37 °C for 1 h, and then subjected to TBE denaturing PAGE gel electrophoresis, which proved that the PAM sequence of BsCpfl was 5'(T)TTN- (Fig. 6B-E).

[0094] Then, the PAM sequences of the remaining Cpfl proteins were identified by a similar method, and the results are shown in Fig.7. The experimental results show that the selected Cpfl proteins all have in vitro enzymatic activity. The PAM sequence of 9 of the Cpfl proteins is 5'(T)TTN-. The PAM sequences of C6Cpf1, HkCpfl and PsCpfl are 5'(T)YYN-.

[0095] To confirm that the PAM sequence for in vivo editing of HkCpfl is 5'(T)YYN-, the HkCpfl vector was transfected into 293T cells with the targeted crRNA vector at 8 sites on the human AAVS1 gene, respectively. The experimental results show that (Fig. 8), HkCpfl can edit 7 of the sites and generate mutations, and the PAM sequence is 5'(T)YYN- (underlined portion of Fig. 8B).Example 4. Genome Editing in Mouse

[0096] To extend the applicability of these Cpfl proteins, a number of transfection experiments were performed in mouse EpiSC cell lines.

[0097] First, we transfected EpiSC cells with the BsCpfl vector and the crRNA vectors (pUC19-crRNA) targeting eight sites on the mouse Tet1 gene, respectively. It was confirmed by T7EI digestion and DNA sequencing that BsCpfl caused gene mutations at sites 2, 3 and 7 (Fig. 9A). The PAM sequence of site 7 was 5'TTA-, and the result was in agreement with the conclusion of Example 3. This indicates that the BsCpfl protein uses the 5' TTN-PAM sequence.

[0098] Next, the DNA editing ability of ArCpfl, BsCpfl, HkCpfl, and PxCpfl was repeatedly verified. Co-transfection was carried out with the crRNA vectors (pUC19-crRNA) targeting eight sites on the mouse MeCP2 gene. Using T7EI digestion and DNA sequencing, it was demonstrated that ArCpfl (Fig. 10 D, E), BsCpfl (Fig. 9B, C), HkCpfl (Fig. 10 F, G) and PxCpfl (Fig. 11 H, I) can target and edit the genome of mouse.

[0099] In addition, the editing ability of ArCpfl, BsCpfl, HkCpfl, LpCpfl, PrCpfl and PxCpfl was further verified by target site 12 of mouse Apob, target site 4 of mouse MeCP2, target site 1 of mouse Nrl and target site 7 of mouse Nrl. The results are shown in Figure 12, and all six proteins can edit the genome. The PAM sequence of site Nrl-7 is 5'TTG, indicating that the PAM sequence of BsCpfl and PrCpfl is 5'TTN-.

[0100] The above experimental results demonstrate that the 12 Cpfl proteins found in the present invention all have DNA editing ability, wherein ArCpfl (SEQ ID NO: 1), BsCpfl (SEQ ID NO: 8), HkCpfl (SEQ ID NO: 4), PxCpfl (SEQ ID NO: 11), LpCpfl (SEQ ID NO: 2) and PrCpfl (SEQ ID NO: 12) enable efficient mammalian genome editing.Example 5. Optimizing the crRNA scaffolds to improve editing efficiency

[0101] This example optimizes the cRNA scaffolds of the newly identified Cpfl proteins that can be used for mammalian genome editing so as to improve the genome editing efficiency of each Cpfl protein (Table 3).

[0102] The experimental results are shown in Fig. 13. Figure 13A shows that cells were transfected with each Cpfl proteins and different crRNA plasmids, and by PCR and T7EI analysis, it demonstrated that different crRNA scaffolds affect the editing efficiency of Cpfl proteins.

[0103] The inventors then established a library of crRNA mutants, transfected with BsCpfl or PrCpfl, respectively. Through PCR and T7EI analysis, crRNA mutants that enable Cpfl to efficiently edit mammalian genome were screened.

[0104] The editing efficiency of the crRNA31 mutant was significantly higher than that of the wild-type crRNA scaffold (crRNA2) derived from the genome of the strain. The cells were transfected with Cpfl, crRNA31, and crRNA2 plasmids, and it was confirmed by PCR and T7EI analysis that crRNA31 can increase the editing efficiency of five Cpfls of ArCpfl, BsCpfl, HkCpfl, PrCpfl, and PxCpfl at the site MeCP2-4 by two folds(Fig. 13B).

[0105] Figures 14A and B show that analysis of different target sites by T7EI confirms that the screened cRNA scaffolds can improve the editing efficiency of BsCpfl and PrCpfl. For PrCpfl, in addition to crRNA31 scaffold, crRNA77, crRNA129 and crRNA159 scaffolds can also significantly improve the editing efficiency at the site Nrl-1.

[0106] Figure 14C shows analysis of intracellular GFP editing efficiency by flow cytometry. crRNA31 scaffold can improve the editing efficiency of BsCpfl and PrCpfl, and crRNA77 and crRNA159 can also significantly improve the editing efficiency of PrCpfl. Table 3. Identified cRNA ScaffoldcRNA ScafflodcrRNA Scafflod Sequence(5' - 3')SEQ ID NOcrRNA 1ATTTCTACtgttGTAGAT25crRNA2ATTTCTACtattGTAGAT26crRNA3ATTTCTACtactGTAGAT27crRNA4ATTTCTACtttgGTAGAT28crRNA5ATTTCTACtagttGTAGAT29crRNA31ATTTCTACTATGGTAGAT30crRNA77ATTTCTACTGTCGTAGAT31crRNA 129ATTTCTACTTGTGTAGAT32crRNA159ATTTCTACTGTGGTAGAT33 Sequence Information

[0107] >SEQ ID NO:1 ArCpf1 >SEQ ID NO:2 LpCpf1 >SEQ ID NO:3 SaCpf1 >SEQ ID NO:4 HkCpfl >SEQ ID NO:5 AbCpf1 >SEQ ID NO:6 BoCpf1 >SEQ ID NO:7 OsCpf1 >SEQ ID N0:8 BsCpf1 >SEQ ID NO:9 PsCpfl >SEQ ID NO:10 C6Cpf1 >SEQ ID NO:11 PxCpf1 >SEQ ID NO:12 PrCpf1 >SEQ ID NO:13 ArCpfl nucleotide sequence >SEQ ID NO:14 LpCpf1 nucleotide sequence >SEQ ID NO:15 SaCpfl nucleotide sequence >SEQ ID NO:16 HkCpf1 nucleotide sequence >SEQ ID NO:17 AbCpf1 nucleotide sequence >SEQ ID NO:18 BoCpf1 nucleotide sequence >SEQ ID NO:19 OsCpf1 nucleotide sequence >SEQ ID NO:20 BsCpfl nucleotide sequence >SEQ ID NO:21 PsCpf1 nucleotide sequence >SEQ ID NO:22 C6Cpf1 nucleotide sequence >SEQ ID NO:23 PxCpf1 nucleotide sequence >SEQ ID NO:24 PrCpf1 nucleotide sequence >SEQ ID NO:25 crRNA1 scaffold sequence ATTTCTACtgttGTAGAT >SEQ ID NO:26 crRNA2 scaffold sequence ATTTCTACtattGTAGAT >SEQ ID NO:27 crRNA3 scaffold sequence ATTTCTACtactGTAGAT >SEQ ID NO:28 crRNA4 scaffold sequence ATTTCTACtttgGTAGAT >SEQ ID NO:29 crRNA5 scaffold sequence ATTTCTACtagttGTAGAT >SEQ ID NO:30 crRNA31 scaffold sequence ATTTCTACTATGGTAGAT >SEQ ID NO:31 crRNA77 scaffold sequence ATTTCTACTGTCGTAGAT >SEQ ID NO:32 crRNA129 scaffold sequence ATTTCTACTTGTGTAGAT >SEQ ID NO:33 crRNA159 scaffold sequence ATTTCTACTGTGGTAGAT

Claims

1. A genome editing system for site-directed modification of a target sequence in the genome of a cell, comprising at least one of the following i) to v): i) a Cpfl protein, and a guide RNA; ii) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and a guide RNA; iii) a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; iv) an expression construct comprising a nucleotide sequence encoding a Cpfl protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA; v) an expression construct comprising a nucleotide sequence encoding a Cpfl protein and a nucleotide sequence encoding a guide RNA; wherein the Cpfl protein comprises an amino acid sequence of SEQ ID NO: 4, 9 or 10, the guide RNA capable of targeting the Cpfl protein to a target sequence in the genome of the cell.

2. The system of claim 1, wherein the Cpfl protein is derived from Helcococcus kunzii, Proteocatella sphenisci, or Candidatus Dojkabacteria.

3. The system of claim 1, wherein the guide RNA is a crRNA.

4. The system of claim 3, wherein the coding sequence of the crRNA comprises a crRNA scaffold sequence set forth in any one of SEQ ID NOs: 25-33, preferably comprises a crRNA scaffold sequence set forth in SEQ ID NO:30.

5. The system of claim 1, wherein the target sequence has the following structure: 5'-TYYN-Nx-3' or 5'-YYN-Nx-3', wherein N is independently selected from A, G, C and T, Y is selected from C and T; x is an integer of 15 ≤ x ≤ 35; Nx represents x consecutive nucleotides.

6. The genome editing system of any one of claims 1-5 for use in treating a disease in a subject in need thereof, wherein the genome editing system is for modifying a gene related with the disease, by introducing said system into a cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence.

7. The system of claim 6, wherein the cell is from a mammal such as human, mouse, rat, monkey, dog, pig, sheep, cattle, cat; a poultry such as chicken, duck, and goose.

8. The system of any one of claims 6-7, wherein the system is introduced into the cell by the following methods: calcium phosphate transfection, protoplast fusion, electroporation, lipofection, microinjection, viral infection (e.g., baculovirus, vaccinia virus, adenovirus, adeno-associated virus, lentivirus and other viruses), gene gun method, PEG-mediated protoplast transformation, Agrobacterium-mediated transformation.

9. A method of modifying a target sequence in the genome of a plant cell, comprising introducing the genome editing system of any one of claims 1-5 into the cell, whereby the guide RNA targets the Cpfl protein to the target sequence in the genome of the cell, resulting in one or more nucleotide substitution, deletion or addition in the target sequence.

10. The method of claim 9, wherein the plant cell is selected from the group consisting of monocots and dicots, rice, corn, wheat, sorghum, barley, soybean, peanut and Arabidopsis thaliana.

11. A pharmaceutical composition for use in treating a disease in a subject in need thereof, comprising the genome editing system of any one of claims 1-5 and a pharmaceutically acceptable carrier, wherein the genome editing system is for modifying a gene related with the disease.

12. The composition of claim 11, wherein the subject is a mammal such as a human.

13. The composition of claim 11, wherein the disease is selected from tumors, inflammation, Parkinson's disease, cardiovascular disease, Alzheimer's disease, autism, drug addiction, age-related macular degeneration, schizophrenia, hereditary diseases.

14. A crRNA, which comprises a crRNA scaffold sequence corresponding to any one of SEQ ID NOs: 25-33, or the coding sequence of which comprises a sequence set forth in any one of SEQ ID NOs: 25-33.

15. The crRNA of claim 14, wherein the crRNA is encoded by a nucleotide sequence selected from: i) 5'-ATTTCTACtgttGTAGAT(SEQ ID NO:25)-Nx-3'; ii) 5'- ATTTCTACtattGTAGAT(SEQ ID NO:26)-Nx-3'; iii) 5'- ATTTCTACtactGTAGAT(SEQ ID NO:27)-Nx-3'; iv) 5'-ATTTCTACtttgGTAGAT(SEQ ID NO:28)-Nx-3'; v) 5'- ATTTCTACtagttGTAGAT(SEQ ID NO:29)-Nx-3'; vi) 5'-ATTTCTACTATGGTAGAT(SEQ ID NO:30)-Nx-3'; vii) 5'- ATTTCTACTGTCGTAGAT(SEQ ID NO:31)-Nx-3'; viii) 5'- ATTTCTACTTGTGTAGAT(SEQ ID NO:32)-Nx-3'; and ix) 5'- ATTTCTACTGTGGTAGAT(SEQ ID NO:33)-Nx-3', wherein Nx represents nucleotide sequence that consists of x consecutive nucleotides, N is independently selected from A, G, C and T; x is an integer of 18 ≤ x ≤ 35, preferably, x=23.