CN116790559B

CN116790559B - HNH domain-fused V-type Cas enzyme and application thereof

Info

Publication number: CN116790559B
Application number: CN202311039065.2A
Authority: CN
Inventors: 段志强; 陈莹; 韩凤鸣
Original assignee: Shandong Shunfeng Biotechnology Co Ltd
Current assignee: Shandong Shunfeng Biotechnology Co Ltd
Priority date: 2023-07-07
Filing date: 2023-08-17
Publication date: 2023-11-28
Anticipated expiration: 2043-08-17
Also published as: CN116790559A

Abstract

The invention belongs to the field of nucleic acid editing, in particular to the technical field of regular clustered interval short palindromic repeat (CRISPR), relates to a V-type Cas enzyme fused with an HNH (human immunodeficiency Virus) structural domain and application thereof, and particularly provides a V-type Cas protein fused with the HNH structural domain and application thereof.

Description

HNH domain-fused V-type Cas enzyme and application thereof

Technical Field

The invention relates to the field of gene editing, in particular to the technical field of regular clustered interval short palindromic repeat (CRISPR). In particular, the invention relates to a V-type Cas protein fusing HNH structural domains and application thereof.

Background

CRISPR/Cas technology is a widely used gene editing technology that uses RNA-guided specific binding of target sequences on the genome and cleavage of DNA to create double strand breaks, site-directed gene editing using biological non-homologous end joining or homologous recombination.

Type II CRISPR endonuclease, such as Cas9, comprising two nuclease domains, HNH domain and RuvC domain. Unlike type II CRISPR endonucleases, type V CRISPR endonucleases, such as Cas12a (alternatively referred to as cpf 1), have only RuvC domain and lack HNH domain; as described in chinese patent CN109207477B, cpf1 lacks the HNH nuclease domain present in Cas9 protein.

The application provides an engineered V-type Cas enzyme, which fuses HNH structural domains in the V-type Cas enzyme, improves editing activity of the V-type Cas enzyme to a certain extent, and has wide application prospect.

Disclosure of Invention

The inventor fuses HNH structural domain in the V-type Cas enzyme, so that the editing activity of the V-type Cas enzyme is improved, and the application range of the V-type Cas enzyme is expanded.

Engineered V-type Cas proteins

In one aspect, the application provides a V-type Cas protein, also referred to as an engineered V-type Cas protein, comprising a parent V-type Cas protein and a HNH domain interposed between two consecutive or non-consecutive amino acids of the parent V-type Cas protein.

The term "the HNH domain is placed between two consecutive or non-consecutive amino acids of the parent V-type Cas protein" is also understood as fusion of the HNH domain between two consecutive or non-consecutive amino acids of the parent V-type Cas protein, or linking of the HNH domain to between two consecutive or non-consecutive amino acids of the parent V-type Cas protein. For example, two consecutive or non-consecutive amino acids of the parent V-type Cas protein are a first amino acid and a second amino acid, one end of the HNH domain is linked to the first amino acid and the other end of the HNH domain is linked to the second amino acid; the connection may be direct connection or through a joint.

The term "linker" as it relates to polypeptide attachment is well known in the art and refers to a chemical group, or a molecule that attaches two molecules or moieties. The linker may consist of a single linker molecule (e.g., a single amino acid), or may include more than one linker molecule. In some embodiments, the linker may be an organic molecule, a group, a polymer, or a chemical moiety, such as a divalent organic moiety. In some embodiments, the linker may be an amino acid or a peptide.

Such linkers are well known in the art and include, but are not limited to, linkers comprising one or more (e.g., 1,2,3,4, or 5) amino acids (e.g., glu or Ser) or amino acid derivatives (e.g., ahx, beta-Ala, GABA, or Ava), or PEG, etc.

In some embodiments, the linker may be a GS linker. In some embodiments, the linker may comprise the amino acid sequence (GGS) n, GS, SG, GSSG (SEQ ID No. 3) or (GGGGS) n (SEQ ID No. 4), wherein n is an integer from 1 to 20 (e.g., 1,2,3,4,5,6,7,8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). In some embodiments, the linker may comprise the amino acid sequence: SGGSGGSGGS (SEQ ID No. 5). In some embodiments, the linker may comprise the amino acid sequence: SGSETPGTSESATPES (SEQ ID No. 6), also known as the XTEN linker. In some embodiments, the linker may comprise the amino acid sequence: SGGSSGGSSGSETPGTSESATPESSGGSSGGS (SEQ ID No. 7), also known as GS-XTEN-GS linker.

In one embodiment, the two consecutive or non-consecutive amino acids of the parent V-type Cas protein are a first amino acid and a second amino acid, with the HNH domain interposed between the first amino acid and the second amino acid. In one embodiment, the first amino acid and the second amino acid are two consecutive amino acids; in other embodiments, the first amino acid and the second amino acid are two discrete amino acids.

In the present invention, HNH domain is a domain having nuclease cleavage activity; it may be HNH domain derived from Cas9, or HNH domain derived from other species; the HNH domain having nuclease cleavage activity can be obtained by a person skilled in the art by conventional technical means, for example, by bioinformatic analysis.

In one embodiment, the HNH domain is a HNH domain derived from Cas 9; in one embodiment, the amino acid sequence of the HNH domain derived from Cas9 has at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.1%, at least 99.2%, at least 99.3%, at least 99.4%, at least 99.5%, at least 99.6%, at least 99.7%, at least 99.8%, or at least 99.9% sequence identity as compared to SEQ ID No.1, and has the biological function of the HNH domain; in one embodiment, the amino acid sequence of the HNH domain derived from Cas9 has a substitution, deletion, or addition of one or more amino acids compared to SEQ ID No.1, e.g., a substitution, deletion, or addition of 1-20 amino acids, as well as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acids, and has the biological function of the HNH domain; preferably, the amino acid sequence of the HNH domain derived from Cas9 is shown in SEQ ID No. 1.

SEQ ID No.1：Cas9

liekiklhdmqegkclysleaipledllnnpfnyevdhiiprsvsfdnsfnnkvlvkqeenskkgnrtpfqylsssdskisyetfkkhilnlakgkgrisktkkeylle。

The term "biological function having an HNH domain" as used herein means that the nucleic acid has a nuclease cleavage activity represented by the HNH domain.

In one embodiment, the parent V-type Cas protein is selected from one or any of Cas12i, cas12j, cas12a, cas12b, cas12d, cas12e, cas12f, cas12g, cas12 h.

In one embodiment, the parent V-type Cas protein is a Cas protein of the Cas12i family, such as Cas12i1, cas12i2, cas12i3, or Cas12i12.

In some embodiments, the parent V-type Cas protein is a native wild-type Cas protein; in other embodiments, the parent V-type Cas protein is an engineered Cas protein, e.g., a Cas protein obtained by site-directed amino acid mutation.

In a preferred embodiment, the parent V-type Cas protein is Cas12i3, and the amino acid sequence of wild-type Cas12i3 (Cas 12f.4 in CN111757889B, herein referred to as Cas12i 3) is shown in SEQ ID No. 2.

SEQ ID No.2：Cas12i3

mkkvevsrpyqslllpnhrkfkyldetwnayksvksllhrflvcaygavpfnkfvevvekvdndqlvlafavrlfrlvpvestsfakvdkanlakslanhlpvgtaipanvqsyfdsnfdpkkymwidcaweadrlaremglsasqfseyattmlwedwlplnkddvngwgsvsglfgegkkedrqqkvkmlnnllngikknppkdytqylkillnafdakshkeavknykgdstgrtasylseksgeitelmleqlmsniqrdigdkqkeislpkkdvvkkylesesgvpydqnlwsqayrnaassikktdtrnfnstlekfknevelrgllsegddveilrskffssefhktpdkfvikpehigfnnkynvvaelyklkaeatdfesafatvkdefeekgikhpiknileyiwnnevpvekwgrvarfnqseekllrikanptvecnqgmtfgnsamvgevlrsnyvskkgalvsgehggrligqnnmiwlemrllnkgkwethhvpthnmkffeevhaynpsladsvnvrnrlyrsedytqlpssitdglkgnpkakllkrqhcalnnmtanvlnpklsftinkknddytviivhsvevskprrevlvgdylvgmdqnqtasntyavmqvvkpkstdaipfrnmwvrfvesgsiesrtlnsrgeyvdqlnhdgvdlfeigdtewvdsarkffnklgvkhkdgtlvdlstaprkayafnnfyfktmlnhlrsnevdltllrneilrvangrfspmrlgslswttlkalgsfkslvlsyfdrlgakemvdkeakdkslfdllvainnkrsnkreertsriasslmtvaqkykvdnavvhvvvegnlsstdrsaskahnrntmdwcsravvkkledmcnlygfnikgvpafytshqdplvhradyddpkpalrcryssysradfskwgqnalaavvrwasnkksntcykvgaveflkqhglfadkkltveqflskvkdeeiliprrggrvfltthrllaestfvylngvkyhscnadevaavniclndwvipckkkmkeessasg。

In one embodiment, the amino acid sequence of the parent V-type Cas protein has at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.1%, at least 99.2%, at least 99.3%, at least 99.4%, at least 99.5%, at least 99.6%, at least 99.7%, at least 99.8%, or at least 99.9% sequence identity as compared to SEQ ID No. 2.

In one embodiment, the amino acid sequence of the parent V-type Cas protein has one or more amino acid substitutions, deletions or additions, e.g., 1-20 amino acid substitutions, deletions or additions, as compared to SEQ ID No.2, as well as1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 amino acid substitutions, deletions or additions.

The mutated Cas12i3 obtained by site-directed amino acid mutation of Cas12i3 can also be used as the parent V-type Cas protein of the present invention, for example, cas12i3 obtained by amino acid mutation described in chinese patent applications No. 2022103148077, 2022102697541, 2022106036073, 2022109432359, 2023100884374, 2023100667809, 2023104503761.

In one embodiment, the mutated Cas12i3 has a mutation at any one or any several of the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: 7 th, 233 th, 267 th, 369 th, 433 th, 165 th, 166 th, 854 th, 266 th, 235 th, 328 th, 599 th; preferably, the amino acids at positions 7, 233, 267, 369, 433, 165, 166, 854, 266, 235, 328 or 599 are all mutated to R.

In one embodiment, the mutated Cas12i3 has a mutation at the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: bit 7.

In one embodiment, the mutated Cas12i3 has a mutation at the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: bit 7, 233, 267, 369 and 433.

In one embodiment, the mutated Cas12i3 has a mutation at the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: 165, 166, 267 and 854.

In one embodiment, the mutated Cas12i3 has a mutation at the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: 266 th, 235 th, 328 th and 599 th.

In a preferred embodiment, the above-described mutated Cas12i3 is mutated to R at amino acids 7, 233, 267, 369, 433, 165, 166, 854, 266, 235, 328 or 599 of the amino acid sequence shown in SEQ ID No. 2.

In one embodiment, the mutated Cas12i3 has a mutation at any one or any several of the following amino acid positions of the amino acid sequence shown in SEQ ID No. 2: 619 th bit, 844 th bit; preferably, amino acid 619 or 844 is mutated to A.

In one embodiment, the parent V-type Cas protein is the wild-type Cas12i3 described above or the mutated Cas12i3 described above.

In one embodiment, the two consecutive or non-consecutive amino acids of the parent V-type Cas protein are a first amino acid and a second amino acid, with the HNH domain interposed between the first amino acid and the second amino acid.

In one embodiment, the first amino acid and the second amino acid are two consecutive amino acids; the first amino acid and the second amino acid are the following amino acid positions corresponding to the amino acid sequence shown in SEQ ID No. 2: 794 amino acids and 795 amino acids.

In one embodiment, the first amino acid and the second amino acid are an amino acid position 794 and an amino acid position 795 corresponding to the amino acid sequence shown in SEQ ID No. 2; in this embodiment, the HNH domain is disposed between the parent V-type Cas protein and the amino acid positions corresponding to amino acid positions 794 and 795 of SEQ ID No. 2.

The amino acid site in the present invention refers to the site from the N-terminus of the amino acid sequence; for example, the 794 th amino acid of the amino acid sequence shown in SEQ ID No.2 refers to the 794 th amino acid position from the N-terminus of SEQ ID No. 2.

In one embodiment, the engineered V-type Cas protein of the invention is selected from any one of the following groups I-III:

I. the engineered V-type Cas protein includes a parent V-type Cas protein and a HNH domain interposed between two consecutive first and second amino acids of the parent V-type Cas protein;

the amino acid sequence of the parent V-type Cas protein is shown as SEQ ID No.2, or the amino acid sequence of the parent V-type Cas protein has at least 80% sequence identity with SEQ ID No.2, or the amino acid sequence of the parent V-type Cas protein has one or more amino acid substitutions, deletions or additions compared with SEQ ID No.2, or the parent V-type Cas protein has mutation at any one or any several amino acid sites of the amino acid sequence shown as SEQ ID No. 2: 7 th, 233 th, 267 th, 369 th, 433 th, 165 th, 166 th, 854 th, 266 th, 235 th, 328 th, 599 th, wherein amino acids at 7 th, 233 th, 267 th, 369 th, 433 th, 165 th, 166 th, 854 th, 266 th, 235 th, 328 th, or 599 th are all mutated to R;

The HNH domain is a HNH domain derived from Cas 9;

the first amino acid and the second amino acid are selected from the following amino acid positions corresponding to the amino acid sequence shown in SEQ ID No. 2: 794 amino acids and 795 amino acids;

II. At least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the engineered V-type Cas protein of I, and substantially retains the biological function of the engineered V-type Cas protein of I;

III, a substitution, deletion, or addition of one or more amino acids compared to the engineered V-type Cas protein of I, e.g., a substitution, deletion, or addition of 1-20 amino acids, and as another example, a substitution, deletion, or addition of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acids; and, the biological function of the engineered V-type Cas protein described in I is substantially preserved.

The biological function of the engineered V-type Cas protein includes the biological function of the parent V-type Cas protein, e.g., activity that binds to a guide RNA, endonuclease activity, or activity that binds to and cleaves at a specific site of a target sequence under the guidance of a guide RNA (including, but not limited to, cis cleavage activity and Trans cleavage activity); the biological function of the engineered V-type Cas protein also includes additional nuclease cleavage activity following fusion of the HNH domain.

It will be apparent to those skilled in the art that the structure of a protein may be altered without adversely affecting its activity and functionality, for example, one or more conservative amino acid substitutions may be introduced into the amino acid sequence of the protein without adversely affecting the activity and/or three-dimensional structure of the protein molecule. Examples and embodiments of conservative amino acid substitutions are apparent to those skilled in the art. In particular, the amino acid residue may be substituted with another amino acid residue belonging to the same group as the site to be substituted, i.e., with a nonpolar amino acid residue, with a polar uncharged amino acid residue, with a basic amino acid residue, with an acidic amino acid residue. Such substituted amino acid residues may or may not be encoded by the genetic code. Conservative substitutions of one amino acid by another belonging to the same group are within the scope of the invention as long as the substitution does not result in inactivation of the biological activity of the protein. Thus, the engineered V-type Cas proteins of the invention may comprise one or more conservative substitutions in the amino acid sequence, which are preferably made according to table 1. In addition, proteins that also contain one or more other non-conservative substitutions are also contemplated by the present invention, provided that the non-conservative substitutions do not significantly affect the desired function and biological activity of the proteins of the present invention.

Conservative amino acid substitutions may be made at one or more predicted nonessential amino acid residues. "nonessential" amino acid residues are amino acid residues that can be altered (deleted, substituted or substituted) without altering the biological activity, whereas "essential" amino acid residues are required for the biological activity. A "conservative amino acid substitution" is a substitution in which an amino acid residue is replaced with an amino acid residue having a similar side chain. Amino acid substitutions may be made in non-conserved regions of the engineered V-type Cas proteins described above. In general, such substitutions are not made to conserved amino acid residues, or amino acid residues that are within a conserved motif, where such residues are required for protein activity. However, it will be appreciated by those skilled in the art that functional variants may have fewer conservative or non-conservative changes in the conserved regions.

TABLE 1

It is well known in the art that one or more amino acid residues may be altered (substituted, deleted, truncated or inserted) from the N-and/or C-terminus of a protein while still retaining its functional activity. Thus, proteins that have one or more amino acid residues altered from the N and/or C terminus of the Cas protein while retaining their desired functional activity are also within the scope of the invention. These changes may include changes introduced by modern molecular methods such as PCR, including PCR amplification that alters or extends the protein coding sequence by including an amino acid coding sequence in the oligonucleotides used in the PCR amplification.

It will be appreciated that proteins may be altered in a variety of ways, including amino acid substitutions, deletions, truncations and insertions, and that methods for such manipulation are generally known in the art. For example, amino acid sequence variants of the above proteins can be prepared by mutation of DNA. Single or multiple amino acid substitutions, deletions and/or insertions may also be made by other forms of mutagenesis and/or by directed evolution, for example, using known mutagenesis, recombination and/or shuffling (shuffleling) methods, in combination with associated screening methods.

Those skilled in the art will appreciate that these minor amino acid changes in the Cas proteins of the invention may occur (e.g., naturally occurring mutations) or be generated (e.g., using r-DNA technology) without loss of protein function or activity. If these mutations occur in the catalytic domain, active site or other functional domain of the protein, the nature of the polypeptide may be altered, but the polypeptide may retain its activity. Smaller effects can be expected if mutations are present that are not close to the catalytic domain, active site or other functional domain.

The skilled artisan can identify the essential amino acids of the engineered V-type Cas proteins of the invention according to methods known in the art, such as site-directed mutagenesis or protein evolution or analysis of bioinformatics. The catalytic, active or other functional domains of a protein can also be determined by physical analysis of the structure, such as by the following techniques: such as nuclear magnetic resonance, crystallography, electron diffraction, or photoaffinity labeling, in combination with mutations in the amino acids at putative key sites.

In the present invention, amino acid residues may be represented by single letters or by three letters, for example: alanine (Ala, A), valine (Val, V), glycine (Gly, G), leucine (Leu, L), glutamine (Gln, Q), phenylalanine (Phe, F), tryptophan (Trp, W), tyrosine (Tyr, Y), aspartic acid (Asp, D), asparagine (Asn, N), glutamic acid (Glu, E), lysine (Lys, K), methionine (Met, M), serine (Ser, S), threonine (Thr, T), cysteine (Cys, C), proline (Pro, P), isoleucine (Ile, I), histidine (His, H), arginine (Arg, R).

The term "AxxB" means that amino acid a in position xx is changed to amino acid B, e.g. E5R means that E in position 5 is mutated to R. When multiple amino acid sites are mutated simultaneously, it can be expressed in terms of E5R-V4R similarity, e.g., E5R-V4R represents the mutation of E at position 5 to R and V at position 4 to R.

The specific amino acid positions (numbering) within the proteins of the invention are determined by aligning the amino acid sequence of the protein of interest with a reference amino acid sequence (e.g., SEQ ID No. 2) using standard sequence alignment tools, such as by aligning the two sequences using the Smith-Waterman algorithm or using the CLUSTALW2 algorithm, wherein the sequences are considered aligned when the alignment is highest. The alignment score can be calculated as described in Wilbur, W.J. and Lipman, D.J. (1983) Rapid similarity searches ofnucleic acid and protein data banks. Proc. Natl. Acad. Sci. USA, 80:726-730. Default parameters are preferably used in the ClustalW2 (1.82) algorithm: protein gap opening penalty = 10.0; protein gap extension penalty = 0.2; protein matrix = Gonnet; protein/DNA endplay= -1; protein/DNAGAPDIST =4. The position of a specific amino acid within a protein according to the invention is preferably determined by aligning the amino acid sequence of the protein with SEQ ID No.2 using the AlignX program (part of the vectorNTI group) with default parameters (gap opening penalty: 10.0 gap extension penalty 0.05) suitable for multiple alignments.

The invention also provides a fusion protein comprising an engineered V-type Cas protein as described above and other modifications.

In one embodiment, the modifying moiety is selected from the group consisting of an additional protein or polypeptide, a detectable label, or any combination thereof.

In one embodiment, the modifying moiety is selected from the group consisting of an epitope tag, a reporter gene sequence, a Nuclear Localization Signal (NLS) sequence, a targeting moiety, a transcriptional activation domain (e.g., VP 64), a transcriptional repression domain (e.g., KRAB domain or SID domain), a nuclease domain (e.g., fok 1), and a domain having an activity selected from the group consisting of: nucleotide deaminase (e.g., adenosine deaminase or cytidine deaminase), methylase activity, demethylase, transcriptional activation activity, transcriptional repression activity, transcriptional release factor activity, histone modification activity, nuclease activity, single-stranded RNA cleavage activity, double-stranded RNA cleavage activity, single-stranded DNA cleavage activity, double-stranded DNA cleavage activity, and nucleic acid binding activity; and any combination thereof. The NLS sequences are well known to those skilled in the art, examples of which include, but are not limited to, the SV40 large T antigen, EGL-13, c-Myc, and TUS proteins.

In one embodiment, the NLS sequence is located at, near, or near the terminus (e.g., N-terminus, C-terminus, or both) of the Cas protein of the invention.

Such epitope tags (tags) are well known to those skilled in the art, including but not limited to His, V5, FLAG, HA, myc, VSV-G, trx, etc., and other suitable epitope tags (e.g., purification, detection, or labeling) may be selected by those skilled in the art.

Such reporter sequences are well known to those skilled in the art, examples of which include, but are not limited to GST, HRP, CAT, GFP, hcRed, dsRed, CFP, YFP, BFP, etc.

In one embodiment, the fusion proteins of the invention comprise a domain capable of binding to a DNA molecule or an intracellular molecule, such as Maltose Binding Protein (MBP), the DNA binding domain of Lex a (DBD), the DBD of GAL4, and the like.

In one embodiment, the fusion proteins of the invention comprise a detectable label, such as a fluorescent dye, e.g., FITC or DAPI.

In one embodiment, the engineered V-type Cas protein of the invention is coupled, conjugated or fused to the modifying moiety, optionally through a linker.

In one embodiment, the modification is directly linked to the N-terminus or C-terminus of the engineered V-type Cas protein of the invention.

In one embodiment, the modification is linked to the N-terminus or C-terminus of the engineered V-type Cas protein of the invention by a linker. Such linkers are well known in the art, examples of which include, but are not limited to, linkers comprising one or more (e.g., 1, 2, 3, 4, or 5) amino acids (e.g., glu or Ser) or amino acid derivatives (e.g., ahx, β -Ala, GABA, or Ava), or PEG, etc.

The engineered V-type Cas protein, protein derivative or fusion protein of the present invention is not limited by the manner in which it is produced, for example, by genetic engineering methods (recombinant techniques) or by chemical synthesis methods.

Nucleic acids for engineered V-type Cas proteins

In another aspect, the invention provides an isolated polynucleotide comprising:

(a) A polynucleotide sequence encoding an engineered V-type Cas protein or fusion protein of the invention;

alternatively, a polynucleotide complementary to the polynucleotide of (a).

In one embodiment, the nucleotide sequence is codon optimized for expression in a prokaryotic cell. In one embodiment, the nucleotide sequence is codon optimized for expression in eukaryotic cells.

In one embodiment, the cell is an animal cell, e.g., a mammalian cell.

In one embodiment, the cell is a human cell.

In one embodiment, the cell is a plant cell, such as a cell of a cultivated plant (e.g., cassava, maize, sorghum, wheat, or rice), algae, tree, or vegetable.

In one embodiment, the polynucleotide is preferably single-stranded or double-stranded.

Guide RNA (gRNA)

In another aspect, the invention provides a gRNA comprising a first segment and a second segment; the first segment is also known as a "framework region", "protein binding segment", "protein binding sequence", or "Direct Repeat (Direct Repeat) sequence"; the second segment is also referred to as a "targeting sequence of a targeting nucleic acid" or a "targeting segment of a targeting nucleic acid", or a "targeting sequence of a targeting nucleic acid".

The first segment of the gRNA is capable of interacting with the Cas protein of the invention, thereby forming a complex of Cas protein and gRNA.

In a preferred embodiment, the first segment is a homeotropic repeat as described above.

The targeting sequence of the targeting nucleic acid or targeting segment of the targeting nucleic acid of the invention comprises a nucleotide sequence complementary to a sequence in the target nucleic acid. In other words, the targeting sequence of the targeting nucleic acid or targeting segment of the targeting nucleic acid of the invention interacts with the target nucleic acid in a sequence-specific manner via hybridization (i.e., base pairing). Thus, the targeting sequence of the targeting nucleic acid or targeting segment of the targeting nucleic acid may be altered, or may be modified to hybridize to any desired sequence within the target nucleic acid. The nucleic acid is selected from DNA or RNA.

The targeting sequence of the targeting nucleic acid or the percentage of complementarity between the targeting segment of the targeting nucleic acid and the target sequence of the target nucleic acid can be at least 60% (e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99%, or 100%).

The "framework region", "protein binding segment", "protein binding sequence", or "cognate repeat" of the gRNA of the invention can interact with a CRISPR protein (or Cas protein). The gRNA of the invention directs its interacting Cas protein to a specific nucleotide sequence within the target nucleic acid through the action of the targeting sequence of the targeting nucleic acid.

Preferably, the guide RNA comprises a first segment and a second segment in the 5 'to 3' direction.

In the context of the present invention, the second segment is also understood as a guide sequence which hybridizes to the target sequence.

The gRNA of the invention is capable of forming a complex with the Cas protein.

Carrier body

The present invention also provides a vector comprising an engineered V-type Cas protein, an isolated nucleic acid molecule, or a polynucleotide as described above; preferably, it further comprises a regulatory element operably linked thereto.

In one embodiment, the regulatory element is selected from one or more of the following group: enhancers, transposons, promoters, terminators, leader sequences, polyadenylation sequences, and marker genes.

In one embodiment, the vector comprises a cloning vector, an expression vector, a shuttle vector, an integration vector.

In some embodiments, the vectors included in the system are viral vectors (e.g., retroviral vectors, lentiviral vectors, adenoviral vectors, adeno-associated vectors, and herpes simplex vectors), but may also be of the plasmid, viral, cosmid, phage, etc. type, which are well known to those skilled in the art.

CRISPR system

The present invention provides an engineered non-naturally occurring vector system, or CRISPR-Cas system, comprising an engineered V-type Cas protein or a nucleic acid sequence encoding the engineered V-type Cas protein and a nucleic acid encoding one or more guide RNAs.

In one embodiment, the nucleic acid sequence encoding the engineered V-type Cas protein and the nucleic acid encoding one or more guide RNAs are synthetic.

In one embodiment, the nucleic acid sequence encoding the engineered V-type Cas protein and the nucleic acid encoding one or more guide RNAs do not co-occur naturally.

The one or more guide RNAs target one or more target sequences in the cell. The one or more target sequences hybridize to a genomic locus of a DNA molecule encoding one or more gene products and the Cas protein is directed to the genomic locus of the DNA molecule of the one or more gene products, and the Cas protein, upon reaching the target sequence position, modifies, edits or cleaves the target sequence, whereby expression of the one or more gene products is altered or modified.

The cells of the invention include one or more of animals, plants or microorganisms.

In some embodiments, the Cas protein is codon optimized for expression in a cell.

In some embodiments, the Cas protein directs cleavage of one or both strands at the target sequence position.

The invention also provides an engineered non-naturally occurring carrier system that can include one or more carriers comprising:

a) A first regulatory element operably linked to the gRNA,

b) A second regulatory element operably linked to the Cas protein;

wherein components (a) and (b) are on the same or different supports of the system.

The first and second regulatory elements include promoters (e.g., constitutive promoters or inducible promoters), enhancers (e.g., 35S promoter or 35S enhanced promoter), internal Ribosome Entry Sites (IRES), and other expression control elements (e.g., transcriptional termination signals, such as polyadenylation signals and poly U sequences).

In some embodiments, the vectors in the system are viral vectors (e.g., retroviral vectors, lentiviral vectors, adenoviral vectors, adeno-associated vectors, and herpes simplex vectors), but may also be of the plasmid, viral, cosmid, phage, etc. type, which are well known to those skilled in the art.

In some embodiments, the systems provided herein are in a delivery system. In some embodiments, the delivery system is a nanoparticle, liposome, exosome, microvesicle, or gene gun.

In one embodiment, the target sequence is a DNA or RNA sequence from a prokaryotic or eukaryotic cell. In one embodiment, the target sequence is a non-naturally occurring DNA or RNA sequence.

In one embodiment, the target sequence is present in a cell. In one embodiment, the target sequence is present in the nucleus or in the cytoplasm (e.g., organelle). In one embodiment, the cell is a eukaryotic cell. In other embodiments, the cell is a prokaryotic cell.

In one embodiment, the Cas protein has one or more NLS sequences attached. In one embodiment, the fusion protein comprises one or more NLS sequences. In one embodiment, the NLS sequence is linked to the N-terminus or C-terminus of the protein. In one embodiment, the NLS sequence is fused to the N-terminus or C-terminus of the protein.

In another aspect, the invention relates to an engineered CRISPR system comprising the Cas protein described above and one or more guide RNAs, wherein the guide RNAs comprise a homodromous repeat sequence and a spacer sequence capable of hybridizing to a target nucleic acid, the Cas protein is capable of binding to the guide RNAs and targeting a target nucleic acid sequence complementary to the spacer sequence.

Protein-nucleic acid complexes/combinationsArticle (B)

In another aspect, the invention provides a complex or composition comprising:

(i) A protein component selected from the group consisting of: the engineered V-type Cas protein, the derivatized protein, or the fusion protein described above, and any combination thereof; and

(ii) A nucleic acid component comprising (a) a guide sequence capable of hybridizing to a target sequence; and (b) a homeotropic repeat capable of binding to the engineered V-type Cas protein of the invention.

The protein component and the nucleic acid component are bound to each other to form a complex.

In one embodiment, the nucleic acid component is a guide RNA in a CRISPR-Cas system.

In one embodiment, the complex or composition is non-naturally occurring or modified. In one embodiment, at least one component of the complex or composition is non-naturally occurring or modified. In one embodiment, the first component is non-naturally occurring or modified; and/or, the second component is non-naturally occurring or modified.

Activated CRISPR complexes

In another aspect, the present invention also provides an activated CRISPR complex comprising: (1) a protein component selected from the group consisting of: the engineered V-type Cas proteins, derivatized proteins, or fusion proteins of the invention, and any combinations thereof; (2) A gRNA comprising (a) a guide sequence capable of hybridizing to a target sequence; and (b) a homeotropic repeat capable of binding to the Cas protein of the invention; and (3) a target sequence that binds to the gRNA. Preferably, the binding is binding to the target nucleic acid through a targeting sequence of the targeting nucleic acid on the gRNA.

The term "activated CRISPR complex", "activated complex" or "ternary complex" as used herein refers to a complex in a CRISPR system where Cas protein, gRNA bind to or are modified with a target nucleic acid.

The Cas proteins and grnas of the invention can form binary complexes that are activated upon binding to a nucleic acid substrate that is complementary to a spacer sequence in the gRNA (or, referred to as, a guide sequence that hybridizes to a target nucleic acid) to form an activated CRISPR complex. In some embodiments, the spacer sequence of the gRNA is perfectly matched to the target substrate. In other embodiments, the spacer sequence of the gRNA matches a portion (continuous or discontinuous) of the target substrate.

In preferred embodiments, the activated CRISPR complex may exhibit a sidebranch nuclease cleavage activity, which refers to the nonspecific cleavage activity or the nicking activity of the activated CRISPR complex on single stranded nucleic acids, also known in the art as trans cleavage activity.

Delivery and delivery compositions

The engineered V-type Cas proteins, grnas, fusion proteins, nucleic acid molecules, vectors, systems, complexes, and compositions of the invention may be delivered by any method known in the art. Such methods include, but are not limited to, electroporation, lipofection, nuclear transfection, microinjection, sonoporation, gene gun, calcium phosphate mediated transfection, cationic transfection, lipofection, dendritic transfection, heat shock transfection, nuclear transfection, magnetic transfection, lipofection, puncture transfection, optical transfection, reagent enhanced nucleic acid uptake, and delivery via liposomes, immunoliposomes, virosomes, artificial virosomes, and the like.

Accordingly, in another aspect, the present invention provides a delivery composition comprising a delivery vehicle, and one or more selected from any of the following: the engineered V-type Cas proteins, fusion proteins, nucleic acid molecules, vectors, systems, complexes, and compositions of the invention.

In one embodiment, the delivery vehicle is a particle.

In one embodiment, the delivery vehicle is selected from the group consisting of a lipid particle, a sugar particle, a metal particle, a protein particle, a liposome, an exosome, a microbubble, a gene gun, or a viral vector (e.g., replication defective retrovirus, lentivirus, adenovirus, or adeno-associated virus).

Host cells

The invention also relates to an in vitro, ex vivo or in vivo cell or cell line or their progeny comprising: the engineered V-type Cas proteins, fusion proteins, nucleic acid molecules, protein-nucleic acid complexes, activated CRISPR complexes, vectors, delivery compositions of the invention are described herein.

In certain embodiments, the cell is a prokaryotic cell.

In certain embodiments, the cell is a eukaryotic cell. In certain embodiments, the cell is a mammalian cell. In certain embodiments, the cell is a human cell. In certain embodiments, the cell is a non-human mammalian cell, e.g., a non-human primate, bovine, ovine, porcine, canine, simian, rabbit, rodent (e.g., rat or mouse) cell. In certain embodiments, the cells are non-mammalian eukaryotic cells, such as cells of poultry birds (e.g., chickens), fish, or crustaceans (e.g., clams, shrimps). In certain embodiments, the cell is a plant cell, e.g., a cell of a monocot or dicot or a cell of a cultivated plant or a food crop such as tapioca, corn, sorghum, soybean, wheat, oat, or rice, e.g., an algae, tree, or production plant, fruit, or vegetable (e.g., a tree such as citrus, nut, eggplant, cotton, tobacco, tomato, grape, coffee, cocoa, etc.).

In certain embodiments, the cell is a stem cell or stem cell line.

In certain instances, a host cell of the invention comprises a modification of a gene or genome that is not present in its wild type.

Gene editing method and application

The engineered type V Cas protein, nucleic acid, the above composition, the above CIRSPR/Cas system, the above vector system, the above delivery composition or the above activated CRISPR complex or the above host cell of the invention can be used for any one or any several of the following uses: targeting and/or editing a target nucleic acid; cleaving double-stranded DNA, single-stranded DNA, or single-stranded RNA; nonspecific cleavage and/or degradation of collateral nucleic acids; nonspecifically cleaving the single-stranded nucleic acid; detecting nucleic acid; detecting nucleic acid in a target sample; editing the double-stranded nucleic acid specifically; base editing double-stranded nucleic acid; base editing single stranded nucleic acids. In other embodiments, it may also be used to prepare reagents or kits for any one or any of several of the uses described above.

The invention also provides the use of the engineered V-type Cas protein, nucleic acid, composition, CIRSPR/Cas system, vector system, delivery composition or activated CRISPR complex described above in gene editing, gene targeting or gene cleavage; alternatively, use in the preparation of a reagent or kit for gene editing, gene targeting or gene cleavage.

In one embodiment, the gene editing, gene targeting or gene cleaving is performed intracellularly and/or extracellularly.

The invention also provides a method of editing, targeting, or cleaving a target nucleic acid comprising contacting the target nucleic acid with the engineered V-type Cas protein, nucleic acid, composition, CIRSPR/Cas system, vector system, delivery composition, or activated CRISPR complex described above. In one embodiment, the method is editing, targeting, or cleaving a target nucleic acid inside or outside a cell.

The gene editing or editing target nucleic acids include modifying genes, knocking out genes, altering expression of gene products, repairing mutations, and/or inserting polynucleotides, gene mutations.

The editing may be performed in prokaryotic and/or eukaryotic cells.

In another aspect, the invention also provides the use of the engineered type V Cas protein, the nucleic acid, the composition, the CIRSPR/Cas system, the vector system, the delivery composition, or the activated CRISPR complex described above in nucleic acid detection, or in the preparation of a reagent or kit for nucleic acid detection.

In another aspect, the invention also provides a method of cleaving a single-stranded nucleic acid, the method comprising contacting a nucleic acid population with the engineered V-type Cas protein and the gRNA described above, wherein the nucleic acid population comprises a target nucleic acid and a plurality of non-target single-stranded nucleic acids, the engineered V-type Cas protein cleaving the plurality of non-target single-stranded nucleic acids.

The gRNA is capable of binding to the Cas protein.

The gRNA is capable of targeting the target nucleic acid.

The contacting may be inside a cell in vitro, ex vivo or in vivo.

Preferably, the cleavage of single-stranded nucleic acid is a nonspecific cleavage.

In another aspect, the invention also provides the use of the engineered type V Cas protein, nucleic acid, composition, CIRSPR/Cas system, vector system, delivery composition or activated CRISPR complex described above for non-specific cleavage of single stranded nucleic acid or for the preparation of a reagent or kit for non-specific cleavage of single stranded nucleic acid.

In another aspect, the invention also provides a kit for gene editing, gene targeting or gene cleavage comprising the engineered type V Cas protein, gRNA, nucleic acid, the composition, the CIRSPR/Cas system, the vector system, the delivery composition, the activated CRISPR complex or the host cell described above.

In another aspect, the invention also provides a kit for detecting a target nucleic acid in a sample, the kit comprising: (a) An engineered V-type Cas protein, or a nucleic acid encoding the Cas protein; (b) A guide RNA, or a nucleic acid encoding the guide RNA, or a precursor RNA comprising the guide RNA, or a nucleic acid encoding the precursor RNA; and (c) a single stranded nucleic acid detector that is single stranded and does not hybridize to the guide RNA.

It is known in the art that precursor RNAs can be cleaved or processed into the mature guide RNAs described above.

In another aspect, the invention provides the use of the engineered type V Cas protein, the nucleic acid, the composition, the CIRSPR/Cas system, the vector system, the delivery composition, the activated CRISPR complex, or the host cell described above in the preparation of a formulation or kit for:

(i) Gene or genome editing;

(ii) Target nucleic acid detection and/or diagnosis;

(iii) Editing a target sequence in a target locus to modify an organism or a non-human organism;

(iv) Treatment of disease;

(iv) Targeting the target gene.

Preferably, the gene or genome editing is performed in or out of a cell.

Preferably, the target nucleic acid detection and/or diagnosis is performed in vitro.

Preferably, the treatment of the disease is treatment of a condition caused by a defect in the target sequence in the target locus.

In another aspect, the invention provides a method of detecting a target nucleic acid in a sample, the method comprising contacting the sample with the engineered type V Cas protein, a gRNA (guide RNA) comprising a region that binds to the Cas protein and a guide sequence that hybridizes to the target nucleic acid, and a single stranded nucleic acid detector; detecting a detectable signal generated by the Cas protein cleaving single-stranded nucleic acid detector, thereby detecting a target nucleic acid; the single stranded nucleic acid detector does not hybridize to the gRNA.

Method for specifically modifying target nucleic acid

In another aspect, the invention also provides a method of specifically modifying a target nucleic acid, the method comprising: contacting a target nucleic acid with the engineered V-type Cas protein, nucleic acid, composition, CIRSPR/Cas system, vector system, delivery composition, or activated CRISPR complex.

The specific modification may occur in vivo or in vitro.

The specific modification may occur either intracellularly or extracellularly.

In some cases, the cell is selected from a prokaryotic cell or a eukaryotic cell, e.g., an animal cell, a plant cell, or a microbial cell.

In one embodiment, the modification refers to cleavage of the target sequence, e.g., single/double strand cleavage of DNA, or single strand cleavage of RNA.

In some cases, the method further comprises contacting the target nucleic acid with a donor polynucleotide, wherein the donor polynucleotide, a portion of the donor polynucleotide, a copy of the donor polynucleotide, or a portion of a copy of the donor polynucleotide is integrated into the target nucleic acid.

In one embodiment, the modification further comprises inserting an editing template (e.g., an exogenous nucleic acid) into the break.

In one embodiment, the method further comprises: contacting an editing template with the target nucleic acid, or delivering into a cell comprising the target nucleic acid. In this embodiment, the method repairs the disrupted target gene by homologous recombination with an exogenous template polynucleotide; in some embodiments, the repair results in a mutation, including an insertion, deletion, or substitution of one or more nucleotides of the target gene, in other embodiments, the mutation results in one or more amino acid changes in a protein expressed from a gene comprising the target sequence.

Detection (non-specific cleavage)

In another aspect, the invention provides a method of detecting a target nucleic acid in a sample, the method comprising contacting the sample with the engineered type V Cas protein, the nucleic acid, the composition, the CIRSPR/Cas system, the vector system, the delivery composition, or the activated CRISPR complex and a single stranded nucleic acid detector; detecting a detectable signal generated by the Cas protein cleaving single stranded nucleic acid detector, thereby detecting a target nucleic acid.

In the present invention, the target nucleic acid comprises ribonucleotides or deoxyribonucleotides; including single-stranded nucleic acids, double-stranded nucleic acids, e.g., single-stranded DNA, double-stranded DNA, single-stranded RNA, double-stranded RNA.

In one embodiment, the target nucleic acid is derived from a sample of a virus, bacterium, microorganism, soil, water source, human, animal, plant, or the like. Preferably, the target nucleic acid is a product of enrichment or amplification by methods such as PCR, NASBA, RPA, SDA, LAMP, HAD, NEAR, MDA, RCA, LCR, RAM.

In one embodiment, the target nucleic acid is a viral nucleic acid, a bacterial nucleic acid, a specific nucleic acid associated with a disease, such as a specific mutation site or SNP site, or a nucleic acid that differs from a control; preferably, the virus is a plant virus or an animal virus, for example, papilloma virus, hepadnavirus, herpes virus, adenovirus, poxvirus, parvovirus, coronavirus; preferably, the virus is a coronavirus, preferably SARS, SARS-CoV2 (COVID-19), HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, mers-CoV.

In the present invention, the gRNA has a degree of match of at least 50%, preferably at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 90% with the target sequence on the target nucleic acid.

In one embodiment, when the target sequence contains one or more characteristic sites (e.g., specific mutation sites or SNPs), the characteristic sites are perfectly matched to the gRNA.

In one embodiment, the detection method may comprise one or more grnas with different targeting sequences to different target sequences.

In the present invention, the single-stranded nucleic acid detector includes, but is not limited to, single-stranded DNA, single-stranded RNA, DNA-RNA hybrids, nucleic acid analogs, base modifications, single-stranded nucleic acid detectors containing abasic spacers, and the like; "nucleic acid analogs" include, but are not limited to: locked nucleic acids, bridged nucleic acids, morpholino nucleic acids, ethylene glycol nucleic acids, hexitol nucleic acids, threose nucleic acids, arabinose nucleic acids, 2' oxymethyl RNAs, 2' methoxyacetyl RNAs, 2' fluoro RNAs, 2' amino RNAs, 4' thio RNAs, and combinations thereof, including optional ribonucleotide or deoxyribonucleotide residues.

In the present invention, the detectable signal is realized by: visual-based detection, sensor-based detection, color detection, fluorescent signal-based detection, gold nanoparticle-based detection, fluorescence polarization, colloidal phase change/dispersion, electrochemical detection, and semiconductor-based detection.

In the present invention, it is preferable that both ends of the single-stranded nucleic acid detector are provided with a fluorescent group and a quenching group, respectively, and that the single-stranded nucleic acid detector may exhibit a detectable fluorescent signal when cleaved. The fluorescent group is selected from one or more of FAM, FITC, VIC, JOE, TET, CY, CY5, ROX, texas Red or LC RED 460; the quenching group is selected from one or more of BHQ1, BHQ2, BHQ3, dabcy1 or Tamra.

In other embodiments, the 5 'end and the 3' end of the single-stranded nucleic acid detector are respectively provided with different labeling molecules, and colloidal gold test results before the single-stranded nucleic acid detector is cleaved by the Cas protein and after the single-stranded nucleic acid detector is cleaved by the Cas protein are detected by a colloidal gold detection mode; the single-stranded nucleic acid detector will exhibit different color development results on the detection line and the quality control line of colloidal gold before being cleaved by Cas protein and after being cleaved by Cas protein.

In some embodiments, the method of detecting a target nucleic acid may further comprise comparing the level of the detectable signal to a reference signal level, and determining the amount of the target nucleic acid in the sample based on the level of the detectable signal.

In some embodiments, the method of detecting a target nucleic acid may further comprise using RNA reporter nucleic acid and DNA reporter nucleic acid (e.g., fluorescent colors) on different channels, and sampling based on combining (e.g., using a minimum or product) the levels of the detectable signals by measuring the signal levels of the RNA and DNA reporter molecules, and determining the levels of the detectable signals by measuring the amounts of target nucleic acid in the RNA and DNA reporter molecules.

In one embodiment, the target gene is present in a cell.

In one embodiment, the cell is a prokaryotic cell.

In one embodiment, the cell is a eukaryotic cell.

In one embodiment, the cell is an animal cell.

In one embodiment, the cell is a human cell.

In one embodiment, the target gene is present in an in vitro nucleic acid molecule (e.g., a plasmid).

In one embodiment, the target gene is present in a plasmid.

HNH domain and application thereof

In another aspect, the invention also provides an HNH domain.

The invention also provides application of the HNH structural domain in improving the editing efficiency of the Cas protein.

The invention also provides application of the HNH structural domain in preparing Cas protein with improved editing efficiency.

In one embodiment, the Cas protein is a V-type Cas protein; preferably, the V-type Cas protein is selected from one or any several of Cas12i, cas12j, cas12a, cas12b, cas12d, cas12e, cas12f, cas12g, and Cas12 h; more preferably, the V-type Cas protein is a Cas protein of the Cas12i family, such as Cas12i1, cas12i2, cas12i3 or Cas12i12.

In one embodiment, the HNH domain described above is placed between two consecutive or non-consecutive amino acids of a Cas protein, thereby enabling an increase in the editing efficiency of the Cas protein.

In one embodiment, the amino acid sequence of the Cas protein has at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.1%, at least 99.2%, at least 99.3%, at least 99.4%, at least 99.5%, at least 99.6%, at least 99.7%, at least 99.8%, or at least 99.9% sequence identity compared to SEQ ID No. 2.

In one embodiment, the amino acid sequence of the Cas protein has one or more amino acid substitutions, deletions, or additions, e.g., 1-20 amino acid substitutions, deletions, or additions, as compared to SEQ ID No.2, as well as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid substitutions, deletions, or additions.

In one embodiment, the two consecutive or non-consecutive amino acids of the Cas protein are a first amino acid and a second amino acid, and the HNH domain is disposed between the first amino acid and the second amino acid.

In one embodiment, the first amino acid and the second amino acid are selected from the following amino acid positions corresponding to the amino acid sequence shown in SEQ ID No. 2: 794 amino acids and 795 amino acids.

Definition of terms

In the present invention, unless otherwise indicated, scientific and technical terms used herein have the meanings commonly understood by one of ordinary skill in the art. Further, the procedures of molecular genetics, nucleic acid chemistry, molecular biology, biochemistry, cell culture, microbiology, cell biology, genomics and recombinant DNA, etc., as used herein, are all conventional procedures widely used in the corresponding field. Meanwhile, in order to better understand the present invention, definitions and explanations of related terms are provided below.

Nucleic acid cleavage or cleavage nucleic acids herein include DNA or RNA cleavage (Cis cleavage), cleavage of DNA or RNA in a side branch nucleic acid substrate (single-stranded nucleic acid substrate) in a target nucleic acid produced by an engineered V-type Cas protein described herein (i.e., non-specific or non-targeted, trans cleavage). In some embodiments, the cleavage is a double-stranded DNA break. In some embodiments, the cleavage is a single-stranded DNA cleavage or a single-stranded RNA cleavage.

CRISPR system

As used herein, the term "regularly clustered, spaced short palindromic repeats (CRISPR) -CRISPR-associated (Cas) (CRISPR-Cas) system" or "CRISPR system" is used interchangeably and has the meaning commonly understood by those skilled in the art, which generally comprises transcripts or other elements related to the expression of a CRISPR-associated ("Cas") gene, or transcripts or other elements capable of directing the activity of the Cas gene.

CRISPR/Cas complexes

As used herein, the term "CRISPR/Cas complex" refers to a complex formed by directing RNA (guide RNA) or mature crRNA to bind to a Cas protein, comprising a direct repeat sequence that hybridizes to a target sequence and binds to a Cas protein, which complex is capable of recognizing and cleaving a polynucleotide that hybridizes to the guide RNA or mature crRNA.

Guide RNA (guide RNA, gRNA)

As used herein, the terms "guide RNA", "mature crRNA", "guide sequence" are used interchangeably and have the meaning commonly understood by those skilled in the art. In general, the guide RNA can comprise, consist essentially of, or consist of a direct repeat (direct repeat) and a guide sequence.

In certain instances, the guide sequence is any polynucleotide sequence that has sufficient complementarity to a target sequence to hybridize to the target sequence and direct specific binding of the CRISPR/Cas complex to the target sequence. In one embodiment, the degree of complementarity between a guide sequence and its corresponding target sequence is at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99% when optimally aligned. It is within the ability of one of ordinary skill in the art to determine the optimal alignment. For example, there are published and commercially available alignment algorithms and programs such as, but not limited to, the Smith-Waterman algorithm (Smith-Waterman), bowtie, geneious, biopython, and SeqMan in ClustalW, matlab.

Target sequence

"target sequence" refers to a polynucleotide targeted by a guide sequence in a gRNA, e.g., a sequence that has complementarity to the guide sequence, wherein hybridization between the target sequence and the guide sequence will promote the formation of a CRISPR/Cas complex (including Cas proteins and grnas). Complete complementarity is not necessary so long as sufficient complementarity exists to cause hybridization and promote the formation of a CRISPR/Cas complex.

The target sequence may comprise any polynucleotide, such as DNA or RNA. In some cases, the target sequence is located either inside or outside the cell. In some cases, the target sequence is located in the nucleus or cytoplasm of the cell. In some cases, the target sequence may be located within an organelle of a eukaryotic cell, such as a mitochondria or chloroplast. Sequences or templates that can be used for recombination into a target locus comprising the target sequence are referred to as "editing templates" or "editing polynucleotides" or "editing sequences". In one embodiment, the editing template is an exogenous nucleic acid. In one embodiment, the recombination is homologous recombination.

In the present invention, a "target sequence" or "target polynucleotide" or "target nucleic acid" may be any polynucleotide that is endogenous or exogenous to a cell (e.g., a eukaryotic cell). For example, the target polynucleotide may be a polynucleotide that is present in the nucleus of a eukaryotic cell. The target polynucleotide may be a sequence encoding a gene product (e.g., a protein) or a non-coding sequence (e.g., a regulatory polynucleotide or unwanted DNA). In some cases, the target sequence should be related to the Protospacer Adjacent Motif (PAM).

Single-stranded nucleic acid detector

The single-stranded nucleic acid detector according to the present invention means a detector comprising a sequence of 2 to 200 nucleotides, preferably 2 to 150 nucleotides, preferably 3 to 100 nucleotides, preferably 3 to 30 nucleotides, preferably 4 to 20 nucleotides, more preferably 5 to 15 nucleotides. Preferably a single-stranded DNA molecule, a single-stranded RNA molecule or a single-stranded DNA-RNA hybrid.

The single-stranded nucleic acid detector comprises different reporter groups or marker molecules at both ends, which do not exhibit a reporter signal when in an initial state (i.e., not cleaved), and which exhibit a detectable signal when cleaved, i.e., a detectable distinction between cleaved and pre-cleaved.

In one embodiment, the reporter or marker molecule comprises a fluorophore and a quencher, wherein the fluorophore is selected from one or more of FAM, FITC, VIC, JOE, TET, CY, CY5, ROX, texas Red or LC RED 460; the quenching group is selected from one or more of BHQ1, BHQ2, BHQ3, dabcy1 or Tamra.

In one embodiment, the single stranded nucleic acid detector has a first molecule (e.g., FAM or FITC) attached to the 5 'end and a second molecule (e.g., biotin) attached to the 3' end. The reaction system containing the single-stranded nucleic acid detector is matched with a flow strip to detect target nucleic acid (preferably, a colloidal gold detection mode). The flow strip is designed with two capture lines, with an antibody binding to a first molecule (i.e., a first molecular antibody) at the sample contact end (colloidal gold), an antibody binding to the first molecular antibody at the first line (control line), and an antibody binding to a second molecule (i.e., a second molecular antibody, such as avidin) at the second line (test line). When the reaction flows along the strip, the first molecular antibody binds to the first molecule carrying the cleaved or uncleaved oligonucleotide to the capture line, the cleaved reporter will bind to the antibody of the first molecular antibody at the first capture line, and the uncleaved reporter will bind to the second molecular antibody at the second capture line. Binding of the reporter group at each line will result in a strong readout/signal (e.g., color). As more reporter is cut, more signal will accumulate at the first capture line and less signal will appear at the second line. In certain aspects, the invention relates to the use of a flow strip as described herein for detecting nucleic acids. In certain aspects, the invention relates to a method of detecting nucleic acids using a flow strip as defined herein, e.g. a (lateral) flow test or a (lateral) flow immunochromatographic assay. In certain aspects, the molecules in the single stranded nucleic acid detector may be interchanged or the positions of the molecules may be changed, so long as the reporting principle is the same or similar to that of the present invention, and the modified manner is also included in the present invention.

The detection method provided by the invention can be used for quantitative detection of target nucleic acid to be detected. The quantitative detection index can be quantified according to the signal intensity of the reporter group, such as the luminous intensity of the fluorescent group, the width of the color-developing strip, and the like.

Wild type

As used herein, the term "wild-type" has the meaning commonly understood by those skilled in the art, which refers to a typical form of an organism, strain, gene, or a characteristic that, when it exists in nature, differs from a mutant or variant form, which may be isolated from a source in nature and not intentionally modified by man.

Derivatization

As used herein, the term "derivatization" refers to a chemical modification of an amino acid, polypeptide, or protein in which one or more substituents have been covalently attached to the amino acid, polypeptide, or protein. Substituents may also be referred to as side chains.

A derivatized protein is a derivative of the protein, in general, derivatization of the protein does not adversely affect the desired activity of the protein (e.g., binding to a guide RNA, endonuclease activity, binding to a specific site of a target sequence under the guidance of a guide RNA and cleavage activity), that is, the derivative of the protein has the same activity as the protein.

Derivatizing proteins

Also referred to as "protein derivatives" refers to modified forms of a protein, for example, wherein one or more amino acids of the protein may be deleted, inserted, modified and/or substituted.

Non-naturally occurring

As used herein, the terms "non-naturally occurring" or "engineered" are used interchangeably and refer to human involvement. When these terms are used to describe a nucleic acid molecule or polypeptide, it means that the nucleic acid molecule or polypeptide is at least substantially free from at least one other component to which it is associated in nature or as found in nature.

Orthologs (orthologs)

As used herein, the term "ortholog" has a meaning commonly understood by those skilled in the art. As a further guidance, an "ortholog" of a protein as described herein refers to a protein belonging to a different species that performs the same or similar function as the protein as its ortholog.

Identity of

As used herein, the term "identity" is used to refer to the match of sequences between two polypeptides or between two nucleic acids. When a position in both sequences being compared is occupied by the same base or amino acid monomer subunit (e.g., a position in each of two DNA molecules is occupied by adenine, or a position in each of two polypeptides is occupied by lysine), then the molecules are identical at that position. The "percent identity" between two sequences is a function of the number of matched positions shared by the two sequences divided by the number of positions to be compared x 100. For example, if 6 out of 10 positions of two sequences match, then the two sequences have 60% identity. For example, the DNA sequences CTGACT and CAGGTT share 50% identity (3 out of 6 positions in total are matched). Typically, the comparison is made when two sequences are aligned to produce maximum identity. Such alignment may be conveniently performed using, for example, a computer program such as the Align program (DNAstar, inc.) Needleman et al (1970) j. Mol. Biol. 48: 443-453. The percent identity between two amino acid sequences can also be determined using algorithms of e.meyers and w.miller (comput. Appl biosci.,4:11-17 (1988)) that have been integrated into the ALIGN program (version 2.0), using PAM120 weight residue tables (weight residue table), gap length penalty of 12, and gap penalty of 4. Furthermore, percent identity between two amino acid sequences can be determined using the Needleman and Wunsch (J MoI biol 48:444-453 (1970)) algorithms that have been incorporated into the GAP program of the GCG software package (available on www.gcg.com) using the Blossum 62 matrix or PAM250 matrix and GAP weights (GAP weights) of 16, 14, 12, 10, 8, 6 or 4 and length weights of 1, 2, 3, 4, 5 or 6.

Carrier body

The term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid molecule linked thereto. Vectors include, but are not limited to, single-stranded, double-stranded, or partially double-stranded nucleic acid molecules; a nucleic acid molecule comprising one or more free ends, free ends (e.g., circular); a nucleic acid molecule comprising DNA, RNA, or both; and other diverse polynucleotides known in the art. The vector may be introduced into a host cell by transformation, transduction or transfection such that the genetic material elements carried thereby are expressed in the host cell. A vector may be introduced into a host cell to thereby produce a transcript, protein, or peptide, including from a protein, fusion protein, isolated nucleic acid molecule, or the like (e.g., a CRISPR transcript, such as a nucleic acid transcript, protein, or enzyme) as described herein. A vector may contain a variety of elements that control expression, including, but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. In addition, the vector may also contain a replication origin.

One type of vector is a "plasmid", which refers to a circular double stranded DNA loop into which additional DNA fragments may be inserted, for example, by standard molecular cloning techniques.

Another type of vector is a viral vector in which a virus-derived DNA or RNA sequence is present in a vector used to package a virus (e.g., retrovirus, replication-defective retrovirus, adenovirus, replication-defective adenovirus, and adeno-associated virus). Viral vectors also comprise polynucleotides carried by a virus for transfection into a host cell. Certain vectors (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors) are capable of autonomous replication in a host cell into which they are introduced.

Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operably linked. Such vectors are referred to herein as "expression vectors".

Host cells

As used herein, the term "host cell" refers to a cell that can be used to introduce a vector, including, but not limited to, prokaryotic cells such as e.g. escherichia coli or bacillus subtilis, eukaryotic cells such as microbial cells, fungal cells, animal cells and plant cells.

Those skilled in the art will appreciate that the design of the expression vector may depend on factors such as the choice of host cell to be transformed, the desired level of expression, and the like.

Regulatory element

As used herein, the term "regulatory element" is intended to include promoters, enhancers, internal Ribosome Entry Sites (IRES), and other expression control elements (e.g., transcription termination signals, such as polyadenylation signals and poly U sequences), the detailed description of which may be found in goldel (Goeddel), gene expression techniques: methods of enzymology (GENE EXPRESSION TECHNOLOGY: METHODS IN ENZYMOLOGY) 185, academic Press (Academic Press), san Diego (San Diego), calif. (1990). In some cases, regulatory elements include those sequences that direct constitutive expression of a nucleotide sequence in many types of host cells as well as those sequences that direct expression of the nucleotide sequence in only certain host cells (e.g., tissue-specific regulatory sequences). Tissue-specific promoters may primarily direct expression in a desired tissue of interest, such as muscle, neurons, bone, skin, blood, specific organs (e.g., liver, pancreas), or specific cell types (e.g., lymphocytes). In some cases, regulatory elements may also direct expression in a time-dependent manner (e.g., in a cell cycle-dependent or developmental stage-dependent manner), which may or may not be tissue or cell type specific. In certain instances, the term "regulatory element" encompasses enhancer elements, such as WPRE; a CMV enhancer; the R-U5' fragment in the LTR of HTLV-I (mol. Cell. Biol., volume 8 (1), pages 466-472, 1988), the SV40 enhancer, and the intron sequence between exons 2 and 3 of rabbit beta-globin (Proc. Natl. Acad. Sci. USA., volume 78 (3), pages 1527-31, 1981).

Promoters

As used herein, the term "promoter" has a meaning well known to those skilled in the art and refers to a non-coding nucleotide sequence located upstream of a gene that is capable of initiating expression of a downstream gene. Constitutive (constitutive) promoters are nucleotide sequences of: when operably linked to a polynucleotide encoding or defining a gene product, it results in the production of the gene product in the cell under most or all physiological conditions of the cell. An inducible promoter is a nucleotide sequence which, when operably linked to a polynucleotide encoding or defining a gene product, results in the production of the gene product in a cell, essentially only when an inducer corresponding to the promoter is present in the cell. Tissue specific promoters are nucleotide sequences that: when operably linked to a polynucleotide encoding or defining a gene product, it results in the production of the gene product in the cell substantially only if the cell is a cell of the tissue type to which the promoter corresponds.

NLS

A "nuclear localization signal" or "nuclear localization sequence" (NLS) is an amino acid sequence that "tags" a protein for introduction into the nucleus by nuclear transport, i.e., a protein with NLS is transported to the nucleus. Typically, NLS contains positively charged Lys or Arg residues exposed at the protein surface. Exemplary nuclear localization sequences include, but are not limited to, NLS from: SV40 large T antigen, EGL-13, c-Myc, and TUS proteins. In some embodiments, the NLS comprises the PKKKRKV (SEQ ID No. 8) sequence. In some embodiments, the NLS comprises the sequence AVKRPAATKKAGQAKKKKLD (SEQ ID No. 9). In some embodiments, the NLS comprises the sequence PAAKRVKLD (SEQ ID No. 10). In some embodiments, the NLS comprises the sequence MSRRRKANPTKLSENAKKLAKEVEN (SEQ ID No. 11). In some embodiments, the NLS comprises the sequence KLKIKRPVK (SEQ ID No. 12). Other nuclear localization sequences include, but are not limited to, the acidic M9 domain of hnRNP A1, the sequences KIPIK and PY-NLS in yeast transcription repressor Mat. Alpha.2.

Operatively connected to

As used herein, the term "operably linked" is intended to mean that the nucleotide sequence of interest is linked to the one or more regulatory elements in a manner that allows for expression of the nucleotide sequence (e.g., in an in vitro transcription/translation system or in a host cell when the vector is introduced into the host cell).

Complementarity and method of detecting complementary

As used herein, the term "complementarity" refers to the ability of a nucleic acid to form one or more hydrogen bonds with another nucleic acid sequence by means of a conventional watson-crick or other non-conventional type. Percent complementarity means the percentage of residues in a nucleic acid molecule that can form hydrogen bonds (e.g., watson-Crick base pairing) with a second nucleic acid sequence (e.g., 5, 6, 7, 8, 9, 10 of 10 are 50%, 60%, 70%, 80%, 90%, and 100% complementary). "fully complementary" means that all consecutive residues of one nucleic acid sequence form hydrogen bonds with the same number of consecutive residues in one second nucleic acid sequence. "substantially complementary" as used herein refers to a degree of complementarity of at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% over a region of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45, 50 or more nucleotides, or to two nucleic acids that hybridize under stringent conditions.

Stringent conditions

As used herein, "stringent conditions" for hybridization refers to conditions under which a nucleic acid having complementarity to a target sequence hybridizes predominantly to the target sequence and does not substantially hybridize to non-target sequences. Stringent conditions are typically sequence-dependent and will vary depending on a number of factors. In general, the longer the sequence, the higher the temperature at which the sequence specifically hybridizes to its target sequence.

Hybridization

The term "hybridization" or "complementary" or "substantially complementary" means that a nucleic acid (e.g., RNA, DNA) comprises a nucleotide sequence that enables it to bind non-covalently, i.e., form base pairs and/or G/U base pairs with another nucleic acid in a sequence-specific, antiparallel manner (i.e., the nucleic acid specifically binds to the complementary nucleic acid), "anneal" or "hybridize".

Hybridization requires that the two nucleic acids contain complementary sequences, although there may be mismatches between bases. Suitable conditions for hybridization between two nucleic acids depend on the length of the nucleic acids and the degree of complementarity, variables well known in the art. Typically, the hybridizable nucleic acid is 8 nucleotides or more in length (e.g., 10 nucleotides or more, 12 nucleotides or more, 15 nucleotides or more, 20 nucleotides or more, 22 nucleotides or more, 25 nucleotides or more, or 30 nucleotides or more).

It will be appreciated that the sequence of a polynucleotide need not be 100% complementary to the sequence of its target nucleic acid to specifically hybridize. Polynucleotides may comprise 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, 98% or more, 99% or more, 99.5% or more, or 100% sequence complementarity to a target region in a target nucleic acid sequence to which it hybridizes.

Hybridization of the target sequence to the gRNA represents that at least 60%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% of the target sequence and the nucleic acid sequence of the gRNA can hybridize to form a complex; or at least 12, 15, 16, 17, 18, 19, 20, 21, 22 or more bases of the nucleic acid sequence representing the target sequence and the gRNA may be complementarily paired and hybridized to form a complex.

Expression of

As used herein, the term "expression" refers to a process whereby a polynucleotide is transcribed from a DNA template (e.g., into mRNA or other RNA transcript) and/or a process whereby the transcribed mRNA is subsequently translated into a peptide, polypeptide, or protein. Transcripts and encoded polypeptides may be collectively referred to as "gene products". If the polynucleotide is derived from genomic DNA, expression may include splicing of mRNA in eukaryotic cells.

Joint

As used herein, the term "linker" refers to a linear polypeptide formed from multiple amino acid residues joined by peptide bonds. The linker of the invention may be an amino acid sequence that is synthesized artificially, or a naturally occurring polypeptide sequence, such as a polypeptide having the function of a hinge region. Such linker polypeptides are well known in the art (see, e.g., holliger, P. Et al (1993) Proc. Natl. Acad. Sci. USA 90:6444-6448; poljak, R. J. Et al (1994) Structure 2:1121-1123).

Treatment of

As used herein, the term "treating" refers to treating or curing a disorder, delaying the onset of symptoms of a disorder, and/or delaying the progression of a disorder.

A subject

As used herein, the term "subject" includes, but is not limited to, various animals, plants, and microorganisms.

Animals

Such as mammals, e.g., bovine, equine, ovine, porcine, canine, feline, lagomorph (e.g., mice or rats), non-human primate (e.g., macaque or cynomolgus) or human. In certain embodiments, the subject (e.g., human) has a disorder (e.g., a disorder resulting from a disease-related gene defect).

Plants and methods of making the same

The term "plant" is understood to mean any differentiated multicellular organism capable of photosynthesis, including crop plants at any stage of maturity or development, in particular monocotyledonous or dicotyledonous plants, vegetable crops, including artichoke, broccoli, sesame seed, leek, asparagus, lettuce (e.g., head lettuce, leaf lettuce), cabbage (bok choy), yellow arrowroot, melons (e.g., melon, watermelon, columbian melon (crenhaw), white melon, cantaloupe), rape crops (e.g., cabbage, broccoli, chinese cabbage, kohlrabi, chinese cabbage), artichoke, carrot, cabbage (napa), okra, onion, celery, parsley, chick pea, parsnip, chicory, pepper, potato, cucurbit (e.g., zucchini, cucumber, zucchini, melon, pumpkin), radish, dried onion, turnip cabbage, purple eggplant (also known as eggplant), salon, chicory, shallot, chicory, garlic, spinach, green onion, melon, green leafy vegetables (greens), beet (sugar beet and fodder beet), sweet potato, lettuce, horseradish, tomato, turnip, spice; fruit and/or vining crops, such as apples, apricots, cherries, nectarines, peaches, pears, plums, prunes, cherries, quince, almonds, chestnuts, hazelnuts, pecans, pistachios, walnuts, oranges, blueberries, boysenberries (boysenberries), redberries, currants, rowfruits, raspberries, strawberries, blackberries, grapes, avocados, bananas, kiwi fruits, persimmons, pomegranates, pineapple, tropical fruits, pome fruits, melons, mangoes, papaya, and litchis; field crops, such as clover, alfalfa, evening primrose, white mango, corn/maize (forage maize, sweet maize, popcorn), hops, jojoba, peanuts, rice, safflower, small grain cereal crops (barley, oat, rye, wheat, etc.), sorghum, tobacco, kapok, leguminous plants (beans, lentils, peas, soybeans), oleaginous plants (rape, mustard, poppy, olives, sunflower, coconut, castor oil plants, cocoa beans, groundnut), arabidopsis, fibrous plants (cotton, flax, jute), camphoraceae (cinnamon, camphordons), or a plant such as coffee, sugar cane, tea, and natural rubber plants; and/or flower bed plants, such as flowering plants, cactus, fleshy plants and/or ornamental plants, and trees, such as forests (broadleaf and evergreen trees, e.g., conifers), fruit trees, ornamental trees, and nut-bearing trees, and shrubs and other seedlings.

Advantageous effects of the invention

According to the invention, through engineering transformation, the HNH structural domain is fused in the V-type Cas protein, so that the activity of the V-type Cas protein is improved, and the application prospect is wide.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, but it will be understood by those skilled in the art that the following drawings and examples are only for illustrating the present invention and are not to be construed as limiting the scope of the present invention. Various objects and advantageous aspects of the present invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments and the accompanying drawings.

Drawings

Fig. 1. Wild-type Cas12i3 fusion HNH domain editing efficiency detection results.

Figure 2. Results of editing efficiency detection of mutated Cas12i3 fusion HNH domains.

FIG. 3 cleavage activity of dCS 12i3 fusion HNH domain on TS and NTS.

Detailed Description

The following examples are only intended to illustrate the invention and are not intended to limit it. The experiments and methods described in the examples were performed substantially in accordance with conventional methods well known in the art and described in various references unless specifically indicated. For example, for the conventional techniques of immunology, biochemistry, chemistry, molecular biology, microbiology, cell biology, genomics and recombinant DNA used in the present invention, reference may be made to Sambrook (Sambrook), friech (Fritsch) and manitis (Maniatis), molecular cloning: laboratory Manual (MOLECULAR CLONING: A LABORATORY MANUAL), edit 2 (1989); the handbook of contemporary molecular biology (CURRENT PROTOCOLS IN MOLECULAR BIOLOGY) (edited by f.m. ausubel (f.m. ausubel) et al, (1987)); series (academic publishing company) of methods in enzymology (METHODS IN ENZYMOLOGY): PCR 2: practical methods (PCR 2:A PRACTICAL APPROACH) (m.j. Maxfresen (m.j. Macpherson), b.d. black ms (b.d. hames) and g.r. taylor (1995)), harlow and Lane (Lane) edits (1988), antibodies: laboratory Manual (ANTIBODIES, A LABORATORY MANUAL), animal cell CULTURE (ANIMAL CELL CULTURE) (R.I. French Lei Xieni (R.I. Freshney) eds. (1987)).

In addition, the specific conditions are not specified in the examples, and the process is carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. Those skilled in the art will appreciate that the examples describe the invention by way of example and are not intended to limit the scope of the invention as claimed. All publications and other references mentioned herein are incorporated by reference in their entirety.

Example 1 acquisition of HNH Domain

The HNH domain of Cas9 with nuclease cleavage activity was obtained by bioinformatic analysis as follows:

example 2 design and editing efficiency validation of engineered V-type Cas proteins

In this example, cas12i3 (cas12f.4 in CN111757889B, in this example, referred to as Cas12i 3) is used as a parent V-type Cas protein, which lacks HNH domain, and the amino acid sequence of wild-type Cas12i3 is shown in SEQ ID No. 2.

SEQ ID No.2：Cas12i3

In this embodiment, the HNH domain from Cas9 (SEQ ID No. 1) is inserted into a different region of the Cas protein shown in SEQ ID No.2, resulting in a Cas12i3 protein with HNH domain fused at different amino acid positions of SEQ ID No. 2. The editing efficiency of the different Cas12i3 proteins was detected using the following manner: reference (Yang, yi, et al, "Highly efficient and rapid detection of the cleavage activity of Cas/gRNA via a fluorescent reporter," Applied biochemistry and biotechnology 180.4 (2016): 655-667.) constructs a fluorescence reporting system suitable for validating Cas12i3 cleavage; wherein, the fluorescent report carrier is provided with RFP and non-luminous GFFP fluorescent protein, and the Cas carrier is provided with CFP fluorescent protein; the TTTTTTAACAGTGGCCTTATTAA (SEQ ID No. 13) target spot on the GFFP sequence was selected for testing, and the editing efficiency was determined by flow sorting the ratio of GFP fluorescence in CFP and RFP after 48h transfection of CHO cells.

The editing efficiency of wild-type Cas12i3 and Cas12i3 proteins fused to HNH domains at different amino acid positions was examined and the results are shown in fig. 1: the different points in fig. 1 represent the editing efficiency of different Cas proteins, where WT is wild-type Cas12i3; most of Cas12i3 fused to HNH domain was lower in editing efficiency than wild-type Cas12i3, but Cas protein fused to HNH domain between amino acids 794 and 795 of Cas12i3 (795-HNH in fig. 1) was significantly better in editing efficiency than wild-type Cas12i 3. 795-HNH is an engineered Cas protein obtained by inserting the HNH domain shown in SEQ ID No.1 between amino acid 794 and amino acid 795 from the N-terminus of SEQ ID No.2 (i.e., the N-terminus of the HNH domain shown in SEQ ID No.1 is directly linked to amino acid 794 of SEQ ID No.2 and the C-terminus of the HNH domain shown in SEQ ID No.1 is directly linked to amino acid 795 of SEQ ID No. 2).

In previous studies, the applicant has performed site-directed mutagenesis on wild-type Cas12i3 to obtain mutated Cas12i3 with improved editing activity, for example, cas protein obtained by mutating amino acids 7, 233, 267, 369 and 433 of wild-type Cas12i3 described in chinese patent application (application number: 2023100884374), which is Cas protein obtained by mutating amino acids 7, 233, 267, 369 and 433 of SEQ ID No.2 to R; as another example, the Cas protein obtained by mutating amino acids 165, 166, 267 and 854 of wild-type Cas12i3 described in Chinese patent application (application number: 2023104503761) is defined as D165R/D166R/D267R/A854R (which is Cas protein obtained by mutating amino acids 165, 166, 267 and 854 of SEQ ID No.2 into R).

To verify the effect of the insertion of the HNH domain on the D165R/D166R/D267R/a854R mutant Cas protein, applicants inserted the HNH domain shown in SEQ ID No.1 between amino acid 794 and amino acid 795 from the N-terminus to an engineered Cas protein D165R/D166R/D267R/a854R-795; the editing efficiency of D165R/D166R/D267R/a854R-795 was examined using the method described above, resulting in higher editing efficiency for the engineered HNH domain-containing Cas protein described above compared to wild-type Cas12i3 (WT), as shown in fig. 2.

To further verify the effect of HNH domain on Cas protein activity, we inactivated the nuclease domain of wild-type Cas12i3, resulting in inactivated Cas12i3, defined as dCas12i3 (which is a nuclease-inactivated Cas protein obtained by mutating amino acid 619 of SEQ ID No.2 to a). Further, insertion of the HNH domain shown in SEQ ID No.1 between amino acid 794 and amino acid 795 from the N-terminus of dCas12i3 results in engineered Cas protein 795-dCas12i3. Then, the corresponding target sequence is amplified by using primers marked by FAM and ROX to carry out in vitro enzyme digestion experiment, FAM-GTATGTTGTGTGGAATTGTG (SEQ ID No. 14); ROX-GCTGCGCGTAACCACCACAC (SEQ ID No. 15); the gRNA utilized was: AGAGAAUGUGUGCAUAGUCACACUCCCCUACGUGCUGCUGAAG (SEQ ID No. 16); after cleavage, sorting was performed using a capillary electrophoresis apparatus, and the cleavage efficiency of Cas protein on TS (target strand, i.e., nucleic acid strand complementary to gRNA) and NTS (non-target strand, nucleic acid strand complementary to target strand) was determined. As a result, as shown in fig. 3, inactivated dCas12i3 did not generate cleavage activity on TS and NTS compared to wild-type Cas12i3, but 795-dCas12i3 fused with HNH domain was able to exhibit significant cleavage activity on TS and NTS compared to dCas12i3.

Although specific embodiments of the invention have been described in detail, those skilled in the art will appreciate that: many modifications and variations of details may be made to adapt to a particular situation and the invention is intended to be within the scope of the invention. The full scope of the invention is given by the appended claims together with any equivalents thereof.

Claims

1. An engineered V-type Cas protein comprising a parent V-type Cas protein and a HNH domain interposed between two consecutive amino acids of the parent V-type Cas protein;

the two consecutive amino acids of the parent V-type Cas protein are a first amino acid and a second amino acid, the HNH domain being interposed between the first amino acid and the second amino acid;

the amino acid sequence of the parent V-type Cas protein is shown as SEQ ID No. 2;

alternatively, the amino acid sequence of the parent V-type Cas protein is mutated as compared to SEQ ID No.2 at the amino acid position of the amino acid sequence shown in SEQ ID No. 2: 165, 166, 267 and 854, all of the 165, 166, 267 and 854 amino acids being mutated to R;

The HNH domain is a HNH domain derived from Cas 9.

2. The engineered V-type Cas protein of claim 1, wherein the amino acid sequence of the HNH domain is set forth in SEQ ID No. 1.

3. A fusion protein comprising the engineered V-type Cas protein of any one of claims 1-2, and other modifications.

4. An isolated polynucleotide, wherein the polynucleotide is a polynucleotide encoding the engineered V-type Cas protein of any one of claims 1-2, or a polynucleotide encoding the fusion protein of claim 3.

5. A vector comprising the polynucleotide of claim 4 operably linked to regulatory elements.

6. A CRISPR-Cas system, characterized in that the system comprises the engineered V-type Cas protein of any one of claims 1-2 and at least one gRNA;

the gRNA is capable of binding to the engineered V-type Cas protein of any one of claims 1-2.

7. A composition, characterized in that it comprises:

(i) A protein component selected from the group consisting of: the engineered V-type Cas protein of any one of claims 1-2 or the fusion protein of claim 3;

(ii) A nucleic acid component that is a gRNA capable of binding to the engineered V-type Cas protein of any one of claims 1-2;

8. An activated CRISPR complex, said activated CRISPR complex comprising:

(ii) A nucleic acid component that is a gRNA comprising a direct repeat sequence capable of binding to the engineered V-type Cas protein of any one of claims 1-2 and a guide sequence capable of targeting a target sequence;

(iii) A target sequence that binds to the gRNA described in (ii).

9. An engineered host cell that is not an animal variety or a plant variety, comprising the engineered type V Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8.

10. The use of the engineered type V Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9 in gene editing, for non-disease diagnostic and therapeutic purposes; or in the preparation of a reagent or kit for gene editing.

11. The use of the engineered type V Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9 in gene cleavage for non-disease diagnostic and therapeutic purposes; alternatively, in the preparation of a reagent or kit for gene cleavage.

12. The use of the engineered type V Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9, for any one or any of several selected from the group consisting of non-disease diagnostic and therapeutic purposes; alternatively, use in the preparation of a reagent or kit for any one or any of the following applications:

Cleaving double-stranded DNA, single-stranded DNA, or single-stranded RNA; nonspecific cleavage and/or degradation of collateral nucleic acids; nonspecifically cleaving the single-stranded nucleic acid; detecting nucleic acid; editing the double-stranded nucleic acid specifically; base editing double-stranded nucleic acid; base editing single stranded nucleic acids.

13. A method of editing, targeting, or cleaving a target nucleic acid, the method being a method for non-disease diagnosis and treatment purposes, the method comprising contacting the target nucleic acid with the engineered V-type Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9.

14. A kit for gene editing comprising the engineered V-type Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9.

15. Use of the engineered type V Cas protein of any one of claims 1-2, or the fusion protein of claim 3, or the polynucleotide of claim 4, or the vector of claim 5, or the CRISPR-Cas system of claim 6, or the composition of claim 7, or the activated CRISPR complex of claim 8, or the host cell of claim 9, in the preparation of a formulation or kit for:

editing a target sequence in a target locus to modify an organism;

alternatively, treatment of the disease.

Use of an HNH domain, which is an HNH domain derived from Cas9, for increasing the editing efficiency of a Cas protein or for preparing a Cas protein with increased editing efficiency,

the HNH domain is disposed between the first amino acid and the second amino acid of the Cas protein, thereby increasing the editing efficiency of the Cas protein;

the amino acid sequence of the Cas protein is shown as SEQ ID No. 2;

Alternatively, the amino acid sequence of the parent V-type Cas protein is mutated as compared to SEQ ID No.2 at the amino acid position of the amino acid sequence shown in SEQ ID No. 2: 165, 166, 267 and 854, the 165, 166, 267 and 854 amino acids being mutated to R.