CN110862983B

CN110862983B - sgRNA guide sequence of specific targeting mouse Gdf5 gene and application thereof

Info

Publication number: CN110862983B
Application number: CN201911070122.7A
Authority: CN
Inventors: 于鸿浩; 肖福英; 韦日明; 岳鹏鹏; 王添贤
Original assignee: Guilin Medical University
Current assignee: Guilin Medical University
Priority date: 2019-11-05
Filing date: 2019-11-05
Publication date: 2021-04-06
Anticipated expiration: 2039-11-05
Also published as: CN110862983A

Abstract

The invention discloses an sgRNA guide sequence of a specific targeting mouse Gdf5 gene and application thereof, belonging to the technical field of medical genetics and molecular biology. The nucleotide sequence corresponding to the sgRNA is a sequence shown in SEQ ID NO. 1. The invention also discloses a method for editing the mouse Gdf5 gene by using the sgRNA guide sequence of the specific target mouse Gdf5 gene. The sgRNA guide sequence disclosed by the invention can mediate Cas9 protein to efficiently cut target DNA, and further can be used for editing mouse Gdf5 gene and influencing the function of mouse Gdf5 gene encoding protein. The sgRNA guide sequence can realize high-efficiency targeting through a CRISPR/Cas9 system, and the efficiency is 100%.

Description

sgRNA guide sequence of specific targeting mouse Gdf5 gene and application thereof

Technical Field

The invention relates to an sgRNA guide sequence of a specific target mouse Gdf5 gene and application thereof, belonging to the technical field of medical genetics and molecular biology.

Background

The CRISPR/Cas system was first discovered in bacteria, and it performs an acquired immune function in eubacteria and archaea, resistant to foreign virus and plasmid invasion. People transform the CRISPR/Cas system of the microorganism by means of genetic engineering, thereby creating a targeting system which can be widely applied to gene editing of higher organisms, namely the CRISPR/Cas9 system. Since 2012, the system has injected strong power for life science and biomedical research, and becomes a research hotspot in recent years. Since 2013, researchers successfully edited genomes in mammalian cells by using the DNA binding activity and endonuclease activity of CRISPR/Cas 9. In a CRISPR/Cas9 system, Cas9 endonuclease is combined to a genome target position by a base complementary pairing principle under the guidance of single-stranded guide RNA (sgRNA) to generate double-stranded DNA breaks (DSBs), so as to trigger a repair mechanism in cells, i.e., non-homologous end joining (NHEJ) or homologous recombination directed repair (HDR), and base deletion or insertion occurs during repair, thereby finally achieving the purpose of gene editing. The key to binding the Cas9 protein to the target is the sgRNA (about 20bp of sequence complementary to the target), and editing of almost any genomic region of interest can be performed by merely changing the sgRNA sequence. Compared with the application of an earlier gene editing technology such as zinc finger protein nucleases (ZFN) or Transcription Activator Like Effector Nucleases (TALENs), the CRISPR/Cas9 system has the advantages of flexible design, low cost, simple operation, high accuracy, simultaneous multi-site targeting and the like.

The name in sgRNA is guide RNA. Cas9 targeted cleavage of DNA in prokaryotes is achieved by the principle that two small RNAs- -crRNA (CRISPR RNA) and tracrRNA (transactivating crRNA) and target sequence complementary recognition are required. At present, the two small RNAs are fused into one RNA, namely sgRNA, by means of genetic engineering. The primary function of sgrnas is to recognize and bind to the target genomic DNA and mediate cleavage of DNA double strands by Cas9 protein. Therefore, whether the sgRNA can efficiently recognize and bind the target gene in a targeted manner is a prerequisite for whether the CRISPR-Cas9 can specifically edit the target gene, especially gene knockout and gene knock-in, and the high efficiency of the sgRNA is very important for the influence of gene targeting. Therefore, the ability to design and prepare sgrnas that efficiently target a target gene is a key to gene editing based on the CRISPR-Cas9 system.

Syndactyly (SYM 1) is an autosomal dominant hereditary disease characterized by syndactyly, fusion of metacarpal and tarsal bones, and individual conductive deafness. The diseased part of the disease mostly occurs at the proximal phalanx and middle phalanx, the proximal phalanx is lengthened, the middle phalanx is shortened, the articular cavity is narrowed, the joint is strong and straight, the fusion can be caused, the deafness, the paranasal alar and the visual dysplasia can also be accompanied, the 2 nd, 3 rd, 4 th and 5 th fingers are often involved, the dysfunction is mainly shown in that the proximal interphalangeal joint can not be bent or bent and stretched and limited, and the clinical characteristics are shown in that the wide variation from the single knuckle to the extreme shortening of the upper limb bone and the lower limb bone. To date, two virulence genes have been identified for SYM1, one being the NOG gene (SYM1A) and the other being growth factor 5 (growth/differentiation factor 5, GDF5, SYM 1B'). SYM1 is a genetic disease that severely affects the patient's ability to work and quality of life, however, the pathogenesis is poorly understood and no good treatment is available.

GDF5 is also called Cartilage morphogenetic protein (CDMP-1) or MP52, its coding gene is Hotten, full length 488kb, and its coding polypeptide contains 501 amino acids, and is composed of signal peptide (1-27aa) at N end, intermediate precursor peptide (28-381aa) and mature peptide (382-501aa) at C end. Cleavage of the translated precursor methionine peptide yields the mature peptide from which it is produced. The mutation of different sites of the gene can cause different human genetic diseases, such as Grebe type (CGT, OMIM 200700) of chondrodysplasia; the Hunter-Thompson type of cartilage dysplasia (Hunter-Thompson type chondrodysplasia, CHTT, OMIM 201250); short finger type C (brachydaylyy type C, BDC, OMIM 113100; short finger type A2 (brachydaylyy type A2, BDA2, OMIM 112600); Du Pan syndrome (Du Pan syndrome, OMIM 228900); congenital vertical talus (CVT, OMIM 192950); multiple-syntosis syndrome, SYNS1, OMIM 186500) and SYM 1. therefore, it is necessary to screen for a clear and typical SYM1 GDF5 pathogenic site and locate the site on the mouse genome, and then target the site by CRISPR/Cas9 system, a mouse Gdf5 gene mutant cell model or a gRNA-directed strategy can be established to accurately simulate SYM1, which is an in-depth understanding of the pathogenic mechanism of 5 gene and therapeutic mechanism of 5 gene, but there is no significant approach to search for Gdf 5. the mouse gene-directed animal model and editing of the sequence, there is a need to provide a sgRNA targeting sequence specifically targeting mouse Gdf5 gene and a method for editing mouse Gdf5 gene by using the sgRNA targeting sequence, which can simulate human SYM1 pathogenic mutation, so as to solve the defects of the prior art.

Disclosure of Invention

One of the purposes of the invention is to provide a sgRNA targeting sequence specifically targeting mouse Gdf5 gene. The sgRNA targeting sequence is designed by referring to a pathogenic mutation site of a human SYM1 Gdf5 gene, then positioning the site on a mouse Gdf5 gene according to the positioned site DNA sequence. The sgRNA guide sequence disclosed by the invention can mediate Cas9 protein to efficiently and specifically cut target DNA, and further can be used for editing mouse Gdf5 gene and influencing the function of mouse Gdf5 gene encoding protein. The sgRNA guide sequence can mediate a CRISPR/Cas9 system to realize high-efficiency targeting, and the efficiency is 100%.

The technical scheme for solving the problems is as follows: a sgRNA guide sequence of a specific targeting mouse Gdf5 gene, wherein a nucleotide sequence corresponding to the sgRNA is a sequence shown in SEQ ID NO. 1.

The nucleotide sequence of the sgRNA is as follows:

SEQ ID NO.1：5'-cgtggtgtataaacagtacg-3'。

the inventors of the present application performed the following work in order to obtain the sgRNA targeting sequence specifically targeting the mouse Gdf5 gene as described above:

the first step is as follows: the pathogenic mutation site of the human GDF5 gene is screened, and the 491 glutamic acid (Glu for short) site of the human GDF5 gene is determined to be a pseudo-mutation site.

SYM1 was caused by a mutation in the GDF5 gene and was screened for 2 pathogenic mutations using the OMIM online database (as shown in table 1). Because the included mutation sites of OMIM are limited, the mutation situation of the human GDF5 gene is screened by using an ExAC database, and 164 mutation sites are screened in total (as shown in Table 2 and FIG. 1). The ClinVar database was then used to search for the pathogenesis of the missense mutation of GDF5, resulting in a total of 3 mutation sites (as shown in table 3). Finally determining the Glu site mutation-simulating site of 491 th site of the human GDF5 gene according to the comprehensive results of the three databases.

The second step is that: positioning the pathogenic mutation site of mouse Gdf5 gene, positioning the Glu site coding sequence of mouse No. 485.

Because the protein sequences and functional domains encoded by the same functional gene may be different due to species differences between human and mouse, the inventors of the present application compared human GDF5 and mouse Gdf5 protein sequences using Clustal Omega online software and found that the Glu site at position 491 of human GDF5 gene corresponds to the Glu site at position 485 of mouse Gdf5 gene (as shown in FIG. 2). Then, a mouse Gdf5 gene sequence is derived from an Ensembl database, a Glu site coding sequence at the 485 th position is located by using Vector NTI software, and then a gene targeting site is designed near the coding sequence.

The third step: gene editing of pathogenic sites: sites conforming to 5' -N (21) GG sequence features are the editing targets of CRISPR/Cas9 system, and then targets near the sequence of the No. 485 Glu site are found.

The gene structure of mouse Gdf5 is different from that of human, and Glu at 491 in the polypeptide chain of human Gdf5 protein corresponds to Glu at 485 in the polypeptide chain of mouse Gdf5 protein. The function of ' Find Motifs ' of Vector NTI software is used for searching sites with 5' -N (21) GG sequence characteristics, all sites which conform to the sequence characteristics are considered as editing targets of CRISPR/Cas9 system, and then targets near Glu coding sequence No. 485 are found (as shown in FIG. 3).

The target sequence of the sgRNA on the Gdf5 gene conforms to the sequence arrangement rule of 5' -N (21) GG, the target sequence of the sgRNA on the Gdf5 gene is located in an exon of the gene, the target sequence of the sgRNA on the Gdf5 gene is located in different common exons in various splicing forms, and the target sequence of the sgRNA on the Gdf5 gene is unique.

The second object of the present invention is to provide a method for editing the mouse Gdf5 gene using the sgRNA targeting sequence specifically targeting the mouse Gdf5 gene. The invention constructs a CRISPR/Cas9 system capable of simulating pathogenic mutation of human Gdf5 gene by utilizing the sgRNA guide sequence of the specific targeted mouse Gdf5 gene, realizes high-efficiency transfection of mouse N2a cells, determines proper positive cell drug screening concentration, realizes genotype analysis of trace cells, is used for non-medical diagnosis or treatment, and has extremely important effect on research of Gdf5 function, I-type glycogen storage disease pathogenic mechanism, related treatment method and the like.

The technical steps for solving the problems are as follows:

step 1: adding accg at the 5' end of the sgRNA guide sequence of the specific targeting mouse Gdf5 gene to synthesize a forward oligonucleotide sequence; simultaneously, obtaining a corresponding DNA complementary strand according to the sgRNA guide sequence of the specific targeted mouse Gdf5 gene, adding aaac at the 5' end of the sgRNA guide sequence to synthesize a reverse oligonucleotide sequence, and annealing the forward oligonucleotide sequence and the reverse oligonucleotide sequence to form a double-stranded DNA fragment with a sticky end;

step 2: digesting a target vector pGL3-U6-sgRNA plasmid shown in SEQ ID No.4 by using Bsa I restriction enzyme to obtain a digestion product pGL3-U6-sgRNA-Bsa I;

and step 3: connecting the double-stranded DNA fragment with the sticky end obtained in the step 1 with the enzyme digestion product pGL3-U6-sgRNA-Bsa I obtained in the step 2, converting the connection product into competent escherichia coli, coating the competent escherichia coli on an LB culture medium containing ampicillin resistance, culturing overnight at 37 ℃ for 20h, selecting a single clone, identifying a positive clone by sequencing with a universal primer U6 shown in SEQ ID No.5, shaking the positive clone, and extracting a plasmid to obtain pGL3-U6-Gdf5-sgRNA plasmid;

and 4, step 4: co-transfecting mouse N2a cells with the pGL3-U6-Gdf5-sgRNA plasmid obtained in the step 3 and the pST1374-NLS-flag-linker-Cas9 expression plasmid shown in SEQ ID NO.6, and obtaining positive sgRNA-Cas9 co-transfected cells after drug screening;

and 5: carrying out cell lysis on the positive sgRNA-Cas9 cotransfected cells obtained in the step (4), carrying out PCR amplification reaction of the DNA of the targeting site by taking the obtained cell lysate as a template, taking the PCR amplification product of the DNA of the targeting site to carry out Sanger sequencing, and if the targeting site has a set peak, primarily confirming that gene editing occurs;

step 6: TA cloning, sequencing and analyzing step 5 preliminarily confirms the genotype of the targeted site with gene editing and obtains mouse cells with the gene editing.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, in step 1, the annealing reaction system specifically comprises: 10 μ M Forward oligonucleotide5 mu L; 10 μ M reverse oligonucleotide, 5 μ L; 10 XT 7 Endonuclease I buffer, 2. mu.L; ddH₂O, 8 mu L; the reaction procedure is specifically as follows: 95 ℃ for 5 min; 95 ℃ to 85 ℃, and-1 ℃/cycle, for 10 cycles; at 85 deg.C to 25 deg.C, -0.1 deg.C/cycle, for 600 cycles, and storing the annealed product at-20 deg.C.

The adoption of the further beneficial effects is as follows: by adopting the reaction system and the reaction program, the forward oligonucleotide sequence and the reverse oligonucleotide sequence can be more accurately matched and complemented, so that the double-stranded DNA fragment with the sticky end can be efficiently formed. Wherein-1 ℃/cycle means one cycle for each 1 ℃ reduction; -0.1 ℃/cycle, meaning one cycle per 0.1 ℃ reduction.

Further, in step 2, the reaction system of enzyme digestion is specifically: pGL3-U6-sgRNA plasmid, 2. mu.g; 10 Xenzyme digestion buffer, 2 uL; bsa I restriction enzyme, 2. mu.L; supplemental ddH₂And O, setting the enzyme digestion reaction system at 37 ℃ for reaction for 3h until the total volume is 20 mu L.

The adoption of the further beneficial effects is as follows: by using the reaction system, pGL3-U6-sgRNA plasmid can be sufficiently digested.

Further, in step 3, the specific method for transforming competent escherichia coli comprises: adding 5 μ L of the ligation product into 30 μ L of competent Escherichia coli, mixing, standing on ice for 25min, performing water bath heat shock at 42 deg.C for 90s, cooling on ice for 2min, adding 150 μ L of LB liquid culture medium, rotating at 220 rpm, activating at 37 deg.C for 30min, and coating on the surface of LB liquid culture medium with ampicillin resistance.

The adoption of the further beneficial effects is as follows: the ligation product can be efficiently transformed into competent Escherichia coli, so that the recombinants are fully activated, and the proportion of positive recombinants is increased.

Further, in step 3, ampicillin was added to the LB medium having ampicillin resistance at a concentration of 50. mu.g/mL.

The adoption of the further beneficial effects is as follows: the LB culture medium with ampicillin resistance is adopted, so that negative escherichia coli can be effectively killed, and the number of positive colonies is increased.

Further, in the step 3, the temperature of the shake bacteria is 37 ℃, the rotating speed is 220 r/min, and the overnight culture is carried out.

Further, in step 3, the extraction of plasmids adopts an endotoxin removing plasmid extraction kit

The adoption of the further beneficial effects is as follows: by adopting the endotoxin-removing plasmid middle extraction kit, high-quality, high-concentration and endotoxin-free plasmids can be obtained, and the subsequent cell transfection efficiency is improved.

The endotoxin-removing plasmid middle-extracting kit can be purchased in the market, for example, the kit can be purchased from Beijing kang century Biotechnology Co., Ltd, and the product number is CW 2105S.

Further, in step 4, the drugs are puromycin with a concentration of 50. mu.g/ml and blasticidin with a concentration of 100. mu.g/ml.

The adoption of the further beneficial effects is as follows: by utilizing puromycin and blasticidin, positive transfected cells of sgRNA-Cas9 can be efficiently screened.

Further, in step 4, the mouse N2a cells were inoculated and cultured in DMEM complete medium containing 10% v/v fetal bovine serum at 37 ℃ and 5% CO before transfection₂Culturing in an incubator, replacing fresh culture medium every 2d-3d, digesting with 0.25% trypsin after the cell confluence reaches 80-90%, then passing through a 6-well plate, and transfecting after 18-20 h and when the cell confluence reaches 60-70%.

The adoption of the further beneficial effects is as follows: mouse N2a cell, a mouse neuroma blast. By using mouse N2a cells, the sgRNA targeting sequence can be verified to have efficient gene editing efficiency. Mouse N2a cell has high exogenous DNA transfection efficiency, high sensitivity to puromycin and blasticidin, and is convenient for drug screening of positive transfected cells.

Mouse N2a cells were transfected using Lipofectamine^TM3000 Transfection Reagent(Invitrogen^TM) A kit. The kit can be purchased commercially, for example, from Thermo Fisher Scientific under the reference L3000015. At transfection, 2.5 μ g of sgRNA expression plasmid and 2.5 μ g of Cas9 plasmid were transfected per well (diameter 34.8 mm).

The fetal bovine serum and DMEM medium are commercially available, such as from Thermo Fisher Scientific, under the designation 16140071 or 11965118, to achieve the same results.

Further, in step 5, the PCR amplification reaction system of the target site DNA is: 2 mu L of cell lysate, 1 mu L of upstream primer, 1 mu L of downstream primer, 2 mu L of dNTP mix, 1 mu L of TaKaRa Ex Taq, 2.5 mu L of 10 XEx Taq Buffer and 25 mu L of sterilized water; the PCR amplification reaction of the target site DNA is carried out by the following procedures: 95 ℃ for 5 min; 35 cycles of 95 ℃, 20s, 57 ℃, 20s, 72 ℃, 25 s; 72 ℃, 5min, 16 ℃, infinity.

Furthermore, the sequence of the upstream primer is shown as SEQ ID NO. 7.

SEQ ID NO.7：5'-ggcaagcgacccagcaagaacc-3'。

Furthermore, the sequence of the downstream primer is shown as SEQ ID NO. 8.

SEQ ID NO.8：5'-tgcaggctgccaggaaacttcg-3'。

The upstream primer and the downstream primer are synthesized by Shanghai Bailegg Biotechnology Limited. The dNTP mix, TaKaRa Ex Taq and 10 XEx Taq Buffer described above were purchased from Baori physician technology (Beijing) Co., Ltd., having a product number RR 001A.

Further, in step 6, the TA clone sequencing specifically comprises: performing gel recovery and purification on the PCR amplification product of the targeted site obtained in the step 5, connecting the purified DNA, and then performing metal bath at 16 ℃ for 1h to obtain a connection product; and transforming the ligation products into competent escherichia coli, coating the competent escherichia coli on an LB (lysogeny broth) culture medium with aminobenzyl resistance, performing overnight culture at 37 ℃ for 20 hours, performing colony PCR (polymerase chain reaction) reaction verification, screening positive clones, and performing Sanger sequencing on the positive clones.

The further beneficial effects of the adoption are as follows: by TA cloning and sequencing, a single PCR product can be connected to a vector, and the genotype of the targeted site can be obtained through sequencing analysis.

The Solution I and PMD19 vectors described above are commercially available, for example, from Baozi physician technology (Beijing) Inc. under the designation 6013.

Further, the linked reaction system is: PCR purified product 40ng, Solution I2.5. mu.L and PMD19 carrier 0.5. mu.L, and water is added to make up to 5. mu.L; the specific method for transforming the competent escherichia coli comprises the following steps: adding 5 μ L of the ligation product into 30 μ L of competent Escherichia coli, mixing, standing on ice for 25min, performing water bath heat shock at 42 deg.C for 90s, cooling on ice for 2min, adding 150 μ L of LB liquid culture medium, rotating at 220 rpm, activating at 37 deg.C for 30min, and coating on the surface of LB liquid culture medium with ampicillin resistance.

Further, ampicillin was 50. mu.g/mL in the LB medium with ampicillin resistance.

The further beneficial effects of the adoption are as follows: the LB culture medium with ampicillin resistance is adopted, so that negative escherichia coli can be effectively killed, and the number of positive colonies is increased.

Furthermore, the colony PCR reaction system is as follows: 1 mu L of colony aqueous solution, 5 mu L of Premix Taq enzyme, 0.5 mu L of upstream primer, 0.5 mu L of downstream primer and 10 mu L of sterilized water; the procedure of the colony PCR reaction was: 95 ℃ for 5 min; 95 ℃, 20s, 60 ℃, 20s, 72 ℃, 25s, 26 cycles; 72 ℃ for 5 min.

Furthermore, the sequence of the upstream primer is shown as SEQ ID NO. 9.

SEQ ID NO.9：5'-gtaaaacgacggccagt-3'。

Furthermore, the sequence of the downstream primer is shown as SEQ ID NO. 10.

SEQ ID NO.10：5'-caggaaacagctatgac-3'。

The upstream primer and the downstream primer are synthesized by Shanghai Bailegg Biotechnology Limited. The Premix Taq enzyme was purchased from Baori physician technology (Beijing) Ltd, and was assigned a product number of R004Q.

Further, the aqueous solution of colonies was prepared by dissolving a monoclonal colony having a diameter of 1mm in 10. mu.L of sterilized water.

The invention has the beneficial effects that:

(1) the sgRNA guide sequence disclosed by the invention can mediate Cas9 protein, efficiently and specifically cuts target DNA, and is further used for editing mouse Gdf5 gene and influencing the function of mouse Gdf5 gene encoding protein. The sgRNA guide sequence can realize high-efficiency targeting by a CRISPR/Cas9 system, and the efficiency is 100%.

(2) The invention constructs a CRISPR/Cas9 system capable of simulating pathogenic mutation of human Gdf5 gene by utilizing the sgRNA guide sequence of the specific targeted mouse Gdf5 gene, is used for the purpose of non-medical diagnosis or treatment, realizes high-efficiency transfection of mouse N2a cells, determines the appropriate positive cell drug screening concentration, realizes the genotype analysis of trace cells, is used for the purpose of non-medical diagnosis or treatment, and has extremely important effect on researching Gdf5 function, I-type glycogen storage disease pathogenic mechanism, related treatment methods and the like.

Drawings

FIG. 1 is a diagram showing the exon structure and mutation of human GDF5 gene in ExAC database. In the figure, the dots represent the mutation sites. The arrow represents the direction of transcription of the gene.

FIG. 2 shows an alignment of human GDF5 and mouse Gdf5 protein sequences. The human Glu491 site and the mouse Glu485 site representing the mutation in the box correspond.

FIG. 3 is a schematic diagram of mouse Gdf5 gene targeting site and sequence simulating human GDF5 gene mutation.

FIG. 4 is a peak sequencing plot of pGL3-U6-Gdf5-sgRNA 1. In the figure, the black shading indicates the correct insertion of the coding sequence of sgRNA1 into the pGL3-U6-sgRNA plasmid vector.

Fig. 5 shows positive transfected cells after sgRNA1-Cas9 drug screening.

Fig. 6 is a sgRNA1 target gene editing sequence.

Fig. 7 is a sgRNA2 target DNA sequence.

Fig. 8 is a sgRNA3 target DNA sequence.

Fig. 9 is an electrophoresis image of PCR products of TA clone positive clones of sgRNA1 targeting site. In the figure, M represents Marker, and the number represents the colony number of TA clone.

Detailed Description

The principles and features of this invention are described below in conjunction with the following detailed drawings, which are given by way of illustration only and are not intended to limit the scope of the invention.

Firstly, screening pathogenic mutation sites of the human Gdf5 gene, and determining glycine (G for short) at the 70 th site of the human Gdf5 gene as a pseudomutation site.

TABLE 1 OMIM database for pathological mutations in articular syndesmosis GDF5 gene

TABLE 2 mutation of human GDF5 gene in ExAC database

Note: the bold part in the table is the site of the pseudomutation; a total of 164 mutation sites were retrieved, and 20 mutation sites are listed in this table.

Table 3 ClinVar database indicates the missense mutation condition of joint adhesion symptom GDF5

Note: the bold part in the table is the site of the pseudomutation.

Secondly, positioning pathogenic mutation sites of mouse Gdf5 gene, and positioning Glu site coding sequence of mouse No. 485.

Thirdly, gene editing of pathogenic sites: sites conforming to 5' -N (21) GG sequence features are the editing targets of CRISPR/Cas9 system, and then targets near the sequence of the No. 485 Glu site are found.

The invention designs sgRNA guide sequences of 3 targeting sites in total, which are respectively sequences shown in SEQ ID NO.1, SEQ ID NO.2 and SEQ ID NO. 3.

SEQ ID NO. 1: 5'-cgtggtgtataaacagtacg-3' (hereinafter referred to as "sgRNA 1").

SEQ ID NO. 2: 5'-gtataaacagtacgaggaca-3' (hereinafter referred to as "sgRNA 2").

SEQ ID NO. 3: 5'-acagtacgaggacatggtcg-3' (hereinafter referred to as "sgRNA 3").

Fourthly, the sgRNA guide sequence is utilized to edit the mouse Gdf5 gene

Step 1: construction of sgRNA expression vector

The forward oligonucleotide sequence was synthesized by adding accg to the 5' end of the 3 sgRNA targeting sequences (Gdf5-M-sg 1)⁺、Gdf5-M-sg2⁺、Gdf5-M-sg3⁺)；

Simultaneously, a corresponding DNA complementary strand is obtained according to the sgRNA guide sequence, and the 5' end of the DNA complementary strand is added with aaac to synthesize a reverse oligonucleotide sequence (Gdf5-M-sg 1)^-、Gdf5-M-sg2^-、Gdf5-M-sg3^-)；

The forward oligonucleotide sequence and the reverse oligonucleotide sequence are annealed to form a double-stranded DNA fragment having a cohesive end. Wherein the annealing reaction system specifically comprises: 10 μ M forward oligonucleotide, 5 μ L; 10 μ M reverse oligonucleotide, 5 μ L; 10 XT 7 Endonuclease I buffer, 2. mu.L; ddH₂O, 8 mu L; the reaction procedure is specifically as follows: 95 ℃ for 5 min; 95 ℃ to 85 ℃, 1 ℃/cycle (i.e., one cycle for each 1 ℃ reduction), for 10 cycles; at 85 ℃ to 12 ℃, the annealing product is stored at-20 ℃ for 600 cycles at-0.1 ℃/cycle (i.e. one cycle for each 0.1 ℃ reduction).

Chemically synthesized forward and reverse oligonucleotides as shown in table 4.

TABLE 4 chemically synthesized Forward and reverse oligonucleotides

Gdf5-M-sg1⁺	5'-accgcgtggtgtataaacagtacg-3'(SEQ ID NO.11)
		Gdf5-M-sg1^-	5'-aaacgtactgtttatacaccacg-3'(SEQ ID NO.12)
Gdf5-M-sg2⁺	5'-accggtataaacagtacgaggaca-3'(SEQ ID NO.13)
		Gdf5-M-sg2-	5'-aaactgtcctcgtactgtttatac-3'(SEQ ID NO.14)
Gdf5-M-sg3⁺	5'-accgacagtacgaggacatggtcg-3'(SEQ ID NO.15)
		Gdf5-M-sg3-	5'-aaaccgaccatgtcctcgtactgt-3'(SEQ ID NO.16)

Step 2: the target vector pGL3-U6-sgRNA plasmid shown in SEQ ID No.4 is digested by Bsa I restriction enzyme to obtain a digestion product pGL3-U6-sgRNA-Bsa I. Wherein the enzyme digestion reaction system specifically comprises: pGL3-U6-sgRNA plasmid, 2. mu.g; 10 Xenzyme digestion buffer, 2 uL; bsa I restriction enzyme, 2. mu.L; supplemental ddH₂And O, setting the enzyme digestion reaction system at 37 ℃ for reaction for 3h until the total volume is 20 mu L.

And step 3: and (2) connecting the double-stranded DNA fragment with the sticky end obtained in the step (1) with the enzyme digestion product pGL3-U6-sgRNA-Bsa I obtained in the step (2), quickly adding 5 mu L of the connection product into 30 mu L of competent escherichia coli, fully and uniformly mixing, standing on ice for 25min, carrying out water bath heat shock at 42 ℃ for 90s, cooling on ice for 2min, adding 150 mu L of LB liquid culture medium, rotating at 220 r/min, and activating at 37 ℃ for 30 min. Then, the cells were plated on ampicillin-resistant LB medium (ampicillin concentration: 50. mu.g/mL) and cultured overnight at 37 ℃ for 20 hours, and then, single colonies were picked up and positive colonies were obtained by PCR with a bacterial solution and agarose gel electrophoresis. Positive clones were cultured overnight with shaking at 37 ℃ and a rotation speed of 220 rpm. Extracting plasmids by using a kit for extracting endotoxin-free plasmids to obtain pGL3-U6-Gdf5-sgRNA1 plasmids, pGL3-U6-Gdf5-sgRNA2 plasmids and pGL3-U6-Gdf5-sgRNA3 plasmids respectively. The above plasmid was sequenced using the universal primer U6 shown in SEQ ID NO.5 to confirm that the target DNA fragment was inserted into a specific site of the vector (as shown in FIG. 4). The endotoxin-removing plasmid middle-extracting kit can be purchased in the market, for example, the kit can be purchased from Beijing kang century Biotechnology Co., Ltd, and the product number is CW 2105S.

SEQ ID NO.5：5'-atggactatcatatgcttaccgta-3'。

And 4, step 4: mouse N2a cells were first inoculated and cultured in DMEM complete medium containing 10% v/v fetal bovine serum at 37 ℃ with 5% CO₂Culturing in an incubator, replacing fresh culture medium every 2d-3d, and digesting with 0.25% trypsin and passaging after the cell confluence reaches 80% -90%. Then, the cells are distributed into 6-well plates, and transfection is carried out when the cell confluence reaches 60% -70% after 18h-20 h.

Using Lipofectamine^TM3000 Transfection Reagent(Invitrogen^TM) The kit is respectively loaded with pGL3-U6-Gdf5-sgRNA1 plasmid, pGL3-U6-Gdf5-sgRNA2 plasmid, pGL3-U6-Gdf5-sgRNA3 plasmid and pST1374-NLS-flag-linker-Cas9 expression plasmid shown in SEQ ID NO.6, and co-transfects mouse N2a cells. The Lipofectamine^TM3000 ransfection Reagent(Invitrogen^TM) The kit may be purchased commercially, e.g. from Thermo Fisher Scientific under the trade designation L3000015. At transfection, 2.5 μ g of sgRNA expression plasmid and 2.5 μ g of pST1374-NLS-flag-linker-Cas9 expression plasmid were transfected per well (34.8 mm diameter).

Puromycin with the concentration of 50 mu g/ml and blasticidin with the concentration of 100 mu g/ml are adopted for drug screening, and positive sgRNA1-Cas9 co-transfected cells, sgRNA2-Cas9 co-transfected cells and sgRNA3-Cas9 co-transfected cells are obtained respectively. The 3 groups of co-transfected cells were washed 3 times with phosphate buffer, then digested with 0.25% trypsin and collected by centrifugation.

And 5: respectively carrying out centrifugation on the positive sgRNA1-Cas9 co-transfected cells (shown in figure 5), the positive sgRNA2-Cas9 co-transfected cells and the positive sgRNA3-Cas9 co-transfected cells obtained in the step 4 at the rotating speed of 8000 rpm for 5min by adopting a TransDirect Animal Tissue PCR kit, removing supernatant, adding 8 mu L of AD1 suspension cell sediment, then taking 8 mu L of liquid to a PCR tube, adding 2 mu L of AD2, and incubating at 55 ℃ for 10min, 95 ℃ and 3 min; adding 8 μ L of AD3, mixing to obtain cell lysates of 4 groups of cells, and storing at-20 deg.C as template for PCR amplification of DNA at target site. The TransDirect Animal Tissue PCR kit can be purchased from commercial products, such as Beijing Quanji Biotech, and has a product number of AD 201-01.

And respectively taking the cell lysates of the 3 groups of cells as templates to perform PCR amplification reaction of the target site DNA. The PCR amplification reaction system of 3 groups of target sites is as follows: 2 μ L of cell lysate, 1 μ L of upstream primer, 1 μ L of downstream primer, 2 μ L of dNTP mix, 1 μ L of TaKaRa Ex Taq, 2.5 μ L of 10 XEx Taq Buffer, and 25 μ L of sterilized water. The sequence of the upstream primer is shown as SEQ ID NO.7, and the sequence of the upstream primer is shown as SEQ ID NO. 7: 5'-ggcaagcgacccagcaagaacc-3' are provided. The sequence of the downstream primer is shown as SEQ ID NO.8, SEQ ID NO. 8: 5'-tgcaggctgccaggaaacttcg-3' are provided.

The two groups of upstream primers and downstream primers are synthesized by Shanghai Bailige biotechnology limited. The dNTP mix, TaKaRa Ex Taq and 10 XEx Taq Buffer described above were purchased from Baori physician technology (Beijing) Co., Ltd., having a product number RR 001A.

The above 3 sets of target site DNA PCR amplification reaction procedures are: the PCR amplification reaction of the target site DNA is carried out by the following procedures: 95 ℃ for 5 min; 35 cycles of 95 ℃, 20s, 57 ℃, 20s, 72 ℃, 25 s; 72 ℃, 5min, 16 ℃, infinity. 5 μ L of PCR amplification products of the 4 groups of target site DNAs were subjected to agarose gel electrophoresis detection with a mass percentage of 1%, and mouse genomic DNA was used as a control.

The PCR products of the 3 groups of target site DNA are respectively taken for Sanger sequencing, and the Sanger sequencing is carried out by Shanghai Baili George Biotech limited. If the target site appears a set peak, the gene editing is preliminarily confirmed. The sequencing results are shown in FIGS. 6-8. Sequencing results show that the sgRNA1 has high-efficiency gene editing in the designed 3 targeting sites, and the sgRNA2 and the sgRNA3 have low efficiency, so that the sgRNA1 site is proved to be a reliable gene editing target.

Performing gel recovery and purification on a PCR product of the amplified sgRNA1 target spot, and connecting the purified DNA, wherein the connection reaction system is as follows: PCR purified product 40ng, Solution I2.5. mu.L and PMD19 carrier 0.5. mu.L, and water is added to make up to 5. mu.L; then, the reaction mixture was subjected to a metal bath at 16 ℃ for 1 hour to obtain a ligation product. The Solution I and PMD19 vectors described above are commercially available, for example, from Baozi physician technology (Beijing) Inc. under the designation 6013.

Adding 5 μ L of the ligation product into 30 μ L of competent Escherichia coli rapidly, mixing, standing on ice for 25min, performing heat shock in 42 deg.C water bath for 90s, cooling on ice for 2min, adding 150 μ L of LB liquid culture medium, rotating at 220 rpm, and activating at 37 deg.C for 30 min. Then, after incubation at 37 ℃ overnight for 20 hours in an ampicillin-resistant LB medium (in which ampicillin was 50. mu.g/mL), confirmation of the colony PCR reaction was carried out. The system of colony PCR reaction is as follows: 1 mu L of colony aqueous solution, 5 mu L of Premix Taq enzyme, 0.5 mu L of upstream primer, 0.5 mu L of downstream primer and 10 mu L of sterilized water. Wherein the colony aqueous solution is prepared by dissolving a monoclonal colony with the diameter of 1mm in 10 mu L of sterilized water. The sequence of the upstream primer is shown as SEQ ID NO.9, and the sequence of the upstream primer is shown as SEQ ID NO. 9: 5'-gtaaaacgacggccagt-3' are provided. The sequence of the downstream primer is shown as SEQ ID NO.10, and the sequence of the downstream primer is shown as SEQ ID NO. 10: 5'-caggaaacagctatgac-3' are provided.

The procedure for colony PCR reaction was: 95 ℃ for 5 min; 95 ℃, 20s, 60 ℃, 20s, 72 ℃, 25s, 26 cycles; and 5min at 72 ℃, and then carrying out electrophoretic identification (as shown in figure 9).

Positive clones were selected and Sanger sequencing was performed on the positive clones. Sanger sequencing was performed by Shanghai Bailey Biotechnology, Inc. Alignment analysis of the sequencing result and the wild type column shows that random insertion and deletion of bases occur at the sgRNA1 target position, and the editing efficiency is 100% respectively (as shown in table 5).

Table 5 sgRNA1 target genotype analysis

Note: bold font represents the target sequence; italicized letters represent the insertion sequence.

Therefore, the sgRNA1 guide sequence can mediate the Cas9 protein to efficiently and specifically cut the target DNA, and is further used for editing the mouse Gdf5 gene and influencing the function of the mouse Gdf5 gene. The sgRNA1 guide sequence can mediate a CRISPR/Cas9 system to realize high-efficiency targeting, and the efficiency is 100%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Sequence listing

<110> Guilin medical college

<120> sgRNA guide sequence of specific target mouse Gdf5 gene and application thereof

<160> 62

<170> SIPOSequenceListing 1.0

<210> 1

<211> 20

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 1

cgtggtgtat aaacagtacg 20

<210> 2

<211> 20

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 2

gtataaacag tacgaggaca 20

<210> 3

<211> 20

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 3

acagtacgag gacatggtcg 20

<210> 4

<211> 4951

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 4

ggtaccgatt agtgaacgga tctcgacggt atcgatcacg agactagcct cgagcggccg 60

cccccttcac cgagggccta tttcccatga ttccttcata tttgcatata cgatacaagg 120

ctgttagaga gataattgga attaatttga ctgtaaacac aaagatatta gtacaaaata 180

cgtgacgtag aaagtaataa tttcttgggt agtttgcagt tttaaaatta tgttttaaaa 240

tggactatca tatgcttacc gtaacttgaa agtatttcga tttcttggct ttatatatct 300

tgtggaaagg acgaaacacc gggagaccga gagagggtct cagttttaga gctagaaata 360

gcaagttaaa ataaggctag tccgttatca acttgaaaaa gtggcaccga gtcggtgctt 420

tttttaaaga attctcgacc tcgagacaaa tggcagtatt catccacaat tttaaaagaa 480

aaggggggat tggggggtac agtgcagggg aaagaatagt agacataata gcaacagaca 540

tacaaactaa agaattacaa aaacaaatta caaaaattca aaattttcgg gtttattaca 600

gggacagcag agatccactt tggccgcggc tcgagggggt tggggttgcg ccttttccaa 660

ggcagccctg ggtttgcgca gggacgcggc tgctctgggc gtggttccgg gaaacgcagc 720

ggcgccgacc ctgggactcg cacattcttc acgtccgttc gcagcgtcac ccggatcttc 780

gccgctaccc ttgtgggccc cccggcgacg cttcctgctc cgcccctaag tcgggaaggt 840

tccttgcggt tcgcggcgtg ccggacgtga caaacggaag ccgcacgtct cactagtacc 900

ctcgcagacg gacagcgcca gggagcaatg gcagcgcgcc gaccgcgatg ggctgtggcc 960

aatagcggct gctcagcagg gcgcgccgag agcagcggcc gggaaggggc ggtgcgggag 1020

gcggggtgtg gggcggtagt gtgggccctg ttcctgcccg cgcggtgttc cgcattctgc 1080

aagcctccgg agcgcacgtc ggcagtcggc tccctcgttg accgaatcac cgacctctct 1140

ccccaggggg atccaccgga gcttaccatg accgagtaca agcccacggt gcgcctcgcc 1200

acccgcgacg acgtccccag ggccgtacgc accctcgccg ccgcgttcgc cgactacccc 1260

gccacgcgcc acaccgtcga tccggaccgc cacatcgagc gggtcaccga gctgcaagaa 1320

ctcttcctca cgcgcgtcgg gctcgacatc ggcaaggtgt gggtcgcgga cgacggcgcc 1380

gcggtggcgg tctggaccac gccggagagc gtcgaagcgg gggcggtgtt cgccgagatc 1440

ggcccgcgca tggccgagtt gagcggttcc cggctggccg cgcagcaaca gatggaaggc 1500

ctcctggcgc cgcaccggcc caaggagccc gcgtggttcc tggccaccgt cggcgtctcg 1560

cccgaccacc agggcaaggg tctgggcagc gccgtcgtgc tccccggagt ggaggcggcc 1620

gagcgcgccg gggtgcccgc cttcctggaa acctccgcgc cccgcaacct ccccttctac 1680

gagcggctcg gcttcaccgt caccgccgac gtcgaggtgc ccgaaggacc gcgcacctgg 1740

tgcatgaccc gcaagcccgg tgcctgacgc ccgccccacg acccgcagcg cccgaccgaa 1800

aggagcgcac gaccccatgc atcggtacct ttaagaccaa tgacttacaa ggcagctgta 1860

gatcttagcc actttctaga gtcggggcgg ccggccgctt cgagcagaca tgataagata 1920

cattgatgag tttggacaaa ccacaactag aatgcagtga aaaaaatgct ttatttgtga 1980

aatttgtgat gctattgctt tatttgtaac cattataagc tgcaataaac aagttaacaa 2040

caacaattgc attcatttta tgtttcaggt tcagggggag gtgtgggagg ttttttaaag 2100

caagtaaaac ctctacaaat gtggtaaaat cgataaggat ccgtcgaccg atgcccttga 2160

gagccttcaa cccagtcagc tccttccggt gggcgcgggg catgactatc gtcgccgcac 2220

ttatgactgt cttctttatc atgcaactcg taggacaggt gccggcagcg ctcttccgct 2280

tcctcgctca ctgactcgct gcgctcggtc gttcggctgc ggcgagcggt atcagctcac 2340

tcaaaggcgg taatacggtt atccacagaa tcaggggata acgcaggaaa gaacatgtga 2400

gcaaaaggcc agcaaaaggc caggaaccgt aaaaaggccg cgttgctggc gtttttccat 2460

aggctccgcc cccctgacga gcatcacaaa aatcgacgct caagtcagag gtggcgaaac 2520

ccgacaggac tataaagata ccaggcgttt ccccctggaa gctccctcgt gcgctctcct 2580

gttccgaccc tgccgcttac cggatacctg tccgcctttc tcccttcggg aagcgtggcg 2640

ctttctcaat gctcacgctg taggtatctc agttcggtgt aggtcgttcg ctccaagctg 2700

ggctgtgtgc acgaaccccc cgttcagccc gaccgctgcg ccttatccgg taactatcgt 2760

cttgagtcca acccggtaag acacgactta tcgccactgg cagcagccac tggtaacagg 2820

attagcagag cgaggtatgt aggcggtgct acagagttct tgaagtggtg gcctaactac 2880

ggctacacta gaaggacagt atttggtatc tgcgctctgc tgaagccagt taccttcgga 2940

aaaagagttg gtagctcttg atccggcaaa caaaccaccg ctggtagcgg tggttttttt 3000

gtttgcaagc agcagattac gcgcagaaaa aaaggatctc aagaagatcc tttgatcttt 3060

tctacggggt ctgacgctca gtggaacgaa aactcacgtt aagggatttt ggtcatgaga 3120

ttatcaaaaa ggatcttcac ctagatcctt ttaaattaaa aatgaagttt taaatcaatc 3180

taaagtatat atgagtaaac ttggtctgac agttaccaat gcttaatcag tgaggcacct 3240

atctcagcga tctgtctatt tcgttcatcc atagttgcct gactccccgt cgtgtagata 3300

actacgatac gggagggctt accatctggc cccagtgctg caatgatacc gcgggaccca 3360

cgctcaccgg ctccagattt atcagcaata aaccagccag ccggaagggc cgagcgcaga 3420

agtggtcctg caactttatc cgcctccatc cagtctatta attgttgccg ggaagctaga 3480

gtaagtagtt cgccagttaa tagtttgcgc aacgttgttg ccattgctac aggcatcgtg 3540

gtgtcacgct cgtcgtttgg tatggcttca ttcagctccg gttcccaacg atcaaggcga 3600

gttacatgat cccccatgtt gtgcaaaaaa gcggttagct ccttcggtcc tccgatcgtt 3660

gtcagaagta agttggccgc agtgttatca ctcatggtta tggcagcact gcataattct 3720

cttactgtca tgccatccgt aagatgcttt tctgtgactg gtgagtactc aaccaagtca 3780

ttctgagaat agtgtatgcg gcgaccgagt tgctcttgcc cggcgtcaat acgggataat 3840

accgcgccac atagcagaac tttaaaagtg ctcatcattg gaaaacgttc ttcggggcga 3900

aaactctcaa ggatcttacc gctgttgaga tccagttcga tgtaacccac tcgtgcaccc 3960

aactgatctt cagcatcttt tactttcacc agcgtttctg ggtgagcaaa aacaggaagg 4020

caaaatgccg caaaaaaggg aataagggcg acacggaaat gttgaatact catactcttc 4080

ctttttcaat attattgaag catttatcag ggttattgtc tcatgagcgg atacatattt 4140

gaatgtattt agaaaaataa acaaataggg gttccgcgca catttccccg aaaagtgcca 4200

cctgacgcgc cctgtagcgg cgcattaagc gcggcgggtg tggtggttac gcgcagcgtg 4260

accgctacac ttgccagcgc cctagcgccc gctcctttcg ctttcttccc ttcctttctc 4320

gccacgttcg ccggctttcc ccgtcaagct ctaaatcggg ggctcccttt agggttccga 4380

tttagtgctt tacggcacct cgaccccaaa aaacttgatt agggtgatgg ttcacgtagt 4440

gggccatcgc cctgatagac ggtttttcgc cctttgacgt tggagtccac gttctttaat 4500

agtggactct tgttccaaac tggaacaaca ctcaacccta tctcggtcta ttcttttgat 4560

ttataaggga ttttgccgat ttcggcctat tggttaaaaa atgagctgat ttaacaaaaa 4620

tttaacgcga attttaacaa aatattaacg tttacaattt cccattcgcc attcaggctg 4680

cgcaactgtt gggaagggcg atcggtgcgg gcctcttcgc tattacgcca gcccaagcta 4740

ccatgataag taagtaatat taaggtacgg gaggtacttg gagcggccgc aataaaatat 4800

ctttattttc attacatctg tgtgttggtt ttttgtgtga atcgatagta ctaacatacg 4860

ctctccatca aaacaaaacg aaacaaaaca aactagcaaa ataggctgtc cccagtgcaa 4920

gtgcaggtgc cagaacattt ctctatcgat a 4951

<210> 5

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 5

atggactatc atatgcttac cgta 24

<210> 6

<211> 9317

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 6

agcgcccaat acgcaaaccg cctctccccg cgcgttggcc gattcattaa tgcagctggc 60

acgacaggtt tcccgactgg aaagcgggca gtgagcgcaa cgcaattaat gtgagttagc 120

tcactcatta ggcaccccag gctttacact ttatgcttcc ggctcgtatg ttgtgtggaa 180

ttgtgagcgg ataacaattt cacacaggaa acagctatga ccatgattac gccaagctct 240

agctagaggt cgacggtata cagacatgat aagatacatt gatgagtttg gacaaaccac 300

aactagaatg cagtgaaaaa aatgctttat ttgtgaaatt tgtgatgcta ttgctttatt 360

tgtaaccatt ataagctgca ataaacaagt tggggtgggc gaagaactcc agcatgagat 420

ccccgcgctg gaggatcatc cagccggcgt cccggaaaac gattccgaag cccaaccttt 480

catagaaggc ggcggtggaa tcgaaatctc gtagcacgtg tcagtcctgc tcctcggcca 540

cgaagtgctt agccctccca cacataacca gagggcagca attcacgaat cccaactgcc 600

gtcggctgtc catcactgtc cttcactatg gctttgatcc caggatgcag atcgagaagc 660

acctgtcggc accgtccgca ggggctcaag atgcccctgt tctcatttcc gatcgcgacg 720

atacaagtca ggttgccagc tgccgcagca gcagcagtgc ccagcaccac gagttctgca 780

caaggtcccc cagtaaaatg atatacattg acaccagtga agatgcggcc gtcgctagag 840

agagctgcgc tggcgacgct gtagtcttca gagatgggga tgctgttgat tgtagccgtt 900

gctctttcaa tgagggtgga ttcttcttga gacaaaggct tggccatggt ttagttcctc 960

accttgtcgt attatactat gccgatatac tatgccgatg attaattgtc aacacgtgct 1020

gatcagatcc gaaaatggat atacaagctc ccgggagctt tttgcaaaag cctaggcctc 1080

caaaaaagcc tcctcactac ttctggaata gctcagaggc agaggcggcc tcggcctctg 1140

cataaataaa aaaaattagt cagccatggg gcggagaatg ggcggaactg ggcggagtta 1200

ggggcgggat gggcggagtt aggggcggga ctatggttgc tgactaattg agatgcatgc 1260

tttgcatact tctgcctgct ggggagcctg gggactttcc acacctggtt gctgactaat 1320

tgagatgcat gctttgcata cttctgcctg ctggggagcc tggggacttt ccacacccta 1380

actgacacac attccacaga attaattcgc gttaaatttt tgttaaatca gctcattttt 1440

taaccaatag gccgaaatcg gcaaaatccc ttataaatca aaagaataga ccgagatagg 1500

gttgagtgtt gttccagttt ggaacaagag tccactatta aagaacgtgg actccaacgt 1560

caaagggcga aaaaccgtct atcagggcga tggcccacta cgtgaaccat caccctaatc 1620

aagttttttg gggtcgaggt gccgtaaagc actaaatcgg aaccctaaag ggagcccccg 1680

atttagagct tgacggggaa agccggcgaa cgtggcgaga aaggaaggga agaaagcgaa 1740

aggagcgggc gctagggcgc tggcaagtgt agcggtcacg ctgcgcgtaa ccaccacacc 1800

cgccgcgctt aatgcgccgc tacagggcgc gtggggatac cccctagagc cccagctggt 1860

tctttccgcc tcagaagcca tagagcccac cgcatcccca gcatgcctgc tattgtcttc 1920

ccaatcctcc cccttgctgt cctgccccac cccacccccc agaatagaat gacacctact 1980

cagacaatgc gatgcaattt cctcatttta ttaggaaagg acagtgggag tggcaccttc 2040

cagggtcaag gaaggcacgg gggaggggca aacaacagat ggctggcaac tagaaggcac 2100

agtcgaggct gatcagcggg tttaaactca atggtgatgg tgatgatgac cggtacgcgt 2160

agaatcgaga ccgaggagag ggttagggat aggcttacct tcgaagggcc cctagtcgcc 2220

gccgagctga gacaggtcga tgcgagtctc gtacagtccg gtaattgact ggtgtatcag 2280

ggtggcatcg agaacttctt tggtagaggt gtaccgcttc ctgtcaatag ttgtatcgaa 2340

atacttgaag gcagcaggag cgcccagatt agtcagagta aagaggtgga taatattctc 2400

tgcttgttcg cgaattggct tgtccctgtg cttattatat gcgctcagca ctttatcgag 2460

gtttgcatcg gccagaataa cccgcttgct gaactcgcta atctgttcaa tgatttcgtc 2520

caggtagtgt ttatgttgct caacaaagag ttgcttctgc tcattgtctt cagggctacc 2580

tttgagtttc tcgtagtggg aggccagata caggaagttc acgtatttgg agggcagagc 2640

cagctcgttt cctttctgca gctctccggc ggaggccagc atccgcttcc taccattctc 2700

cagctcaaag agagagtact tgggcagttt gatgatgaga tctttcttca cttctttata 2760

gcccttagct tccaggaaat cgattggatt cttctcgaag ctggatctct ccataatagt 2820

aattccgagc agctccttaa cagacttgag tttcttggac ttgcctttct ccacttttgc 2880

cacgaccaga acggaataag ccactgtagg ggaatcgaaa ccgccatact tctttgggtc 2940

ccaatctttc ttcctggcga tcagcttgtc agagttccgc tttggcagga tgctctcctt 3000

tgagaatccg ccggtctgca cttcggtctt cttcacgata ttgacttgtg gcatggacag 3060

caccttccgc acagttgcga agtccctgcc tttatcccac acgatttctc ctgtttctcc 3120

gtttgtttcg atcagtgggc gcttccggat ttcgccgtta gccagggtta tctcagtctt 3180

aaagaaattc atgatattag agtagaagaa gtacttggcg gtggctttgc caatctcttg 3240

ctcagacttt gctatcatct tcctcacatc gtagacttta tagtcaccgt acacgaactc 3300

agactccagt ttagggtatt tcttgatcag ggcggtgcca acgacagcat tgagataggc 3360

atcgtgagca tgatggtaat tgtttatttc gcgaactttg tagaattgaa agtccttccg 3420

gaagtcagac accagcttgc tcttcagagt tatcactttc acttccctga tcagcttatc 3480

gttctcatcg tacttagtgt tcatcctaga gtcgaggatt tgtgccacgt gtttggtaat 3540

ctggcgtgtt tcgaccagtt gcctcttaat aaagccggcc ttgtcgagtt cgctcagacc 3600

tcctctttct gccttagtca gattgtcaaa cttccgctgg gtgatcagtt tggcgttgag 3660

gagctgccgc cagtaattct tcatcttctt gaccacctct tctgatggaa cattgtcaga 3720

cttaccgcga ttcttatcgg atctggtcag caccttgttg tcaatggagt catctttgag 3780

gaaggactgt ggaacaatat ggtccacgtc ataatcggac agccggttga tgtcgagttc 3840

ctggtcaacg tacatgtccc gcccgttctg gaggtagtac aggtagagtt tctcgttctg 3900

gagctgtgta ttctccacag ggtgctcctt cagtatctga gatcccagct ccttaattcc 3960

ctcttcgatt cttttcatcc gttcccgaga gttcttctgg cccttctggg tggtttggtt 4020

ctcccttgcc atttcgataa cgatattctc tggcttgtgc cgacccatca ctttgacgag 4080

ttcgtccacg accttgactg tctgcagtat tcccttcttt atggcgggtg atccagcgag 4140

gttggcgatg tgctcgtgca ggctgtcgcc ttgaccgctc acctgtgcct tctggatgtc 4200

ctctttaaat gtcagagagt catcgtgaat cagttgcatg aagttcctgt tagcgaatcc 4260

gtcggatttc aggaaatcca ggatggtctt tccgctctgt ttgtcgcgga tgccgtttat 4320

gagtttcctg gagagtctac cccacccagt gtagcgccgc cgcttgagct gtttcatgac 4380

tttatcgtca aacagatggg cataggtctt caggcgctct tcgatcatct ctctatcctc 4440

gaacagagtc agggtcagca cgatatcttc caggatgtcc tcgttctcct cattatcgag 4500

gaaatctttg tctttgatta tcttcagcag atcatggtaa gtgcccaggc tggcattaaa 4560

gcggtcctcc acgccagaga tttccactga gtcaaagcat tcgatcttct taaagtaatc 4620

ctccttgagc tgcttcactg tcacctttct attagtcttg aagagcagat caacgatagc 4680

cttcttctgc tctccggaca ggaaggcagg cttcctcatg ccctcggtca cgtacttcac 4740

tttagtcagc tcgttataga cggtgaaata ctcgtacagg agtgaatgtt tgggcaggac 4800

cttctcgttg ggcaggttct tatcgaaatt ggtcatccgt tcgatgaatg actgggcgct 4860

tgcgccctta tccacgacct cttcgaagtt ccaaggagta attgtctcct cagatttcct 4920

ggtcatccaa gcgaagcggg agttgcctct agccagaggg ccgacgtaat aagggatcct 4980

gaaggtcagg atcttctcta tcttctcccg gttatccttc aggaaaggat agaaatcctc 5040

ctgcctgcgg aggattgcat gcagctctcc caggtgtatc tgatgtggaa tggagccatt 5100

atcaaaggtc ctctgcttcc tcagcaggtc ctccctgttc agcttcacca gcagctcttc 5160

agtaccgtcc atcttctcga ggattggttt gatgaacttg taaaattctt cctgtgatgc 5220

tccgccatcg atgtatccgg catatccatt cttgctctgg tcgaagaata tctctttgta 5280

cttctctggc agctgttgcc tcacgagggc tttgagcaga gtcaggtctt gatggtgttc 5340

atcatagcgt tttatcatgg aggcgctcag aggtgctttg gtgatctcag tgttgacccg 5400

gagtatgtcg ctcagcagaa tggcgtcgga gagattctta gcagccagaa agagatcggc 5460

gtactggtcg cctatctgtg cgagcaggtt gtccagatca tcgtcatagg tgtccttgga 5520

gagctggagt ttagcatctt cggccagatc aaaattggac ttgaagttag gtgtcaggcc 5580

caggctcagg gcgatgaggt tcccaaacag gccgttcttc ttttctcctg gcagttgggc 5640

aatcagattc tccagtctgc gtgacttgga cagccgagcg gacagaatag ccttggcatc 5700

cacaccagaa gcgtttatgg gattctcctc gaacagttgg ttatatgtct gcaccagttg 5760

aatgaagagt ttatccacat cggaattatc gggattcagg tcgccctcga tcagaaagtg 5820

tcctctaaac tttatcatat gagccagggc cagatagatg agcctcaggt ctgctttatc 5880

ggtgctgtcc accagcttct tcctcagatg gtagattgta ggatactttt catggtaagc 5940

cacctcatcc acgatatttc cgaatatagg gtgcctctcg tgtttcttat cctcctccac 6000

cagaaagctc tcttccaggc ggtgaaagaa ggagtcgtcc accttagcca tttcgttgct 6060

aaagatctct tgcagataac atatccgatt cttgcggcgg gtgtatctcc gccttgcggt 6120

ccgcttcagc cgagtagctt cagcggtttc accggagtcg aagaggagtg ctccgatcag 6180

gttcttcttg attgaatggc ggtcagtatt acccagcacc ttgaatttct tgcttggcac 6240

cttatactcg tcggttatga cggcccagcc aacggagttt gtcccgatat ccagtccaat 6300

agagtatttc ttgtctctag tgtgggtccg ctggtgtctg gtcagagcac cagactgaga 6360

gaaagattta ccacactctg ggcatttgta tggcttctcg ccgggttcca gtctagattt 6420

atcgtcgtca tccttgtagt cagcggccgc caccttcctc tttttcttag gtcccatggt 6480

gctagccagc ttgggtctcc ctatagtgag tcgtattaat ttcgataagc cagtaagcag 6540

tgggttctct agttagccag agagctctgc ttatatagac ctcccaccgt acacgcctac 6600

cgcccatttg cgtcaatggg gcggagttgt tacgacattt tggaaagtcc cgttgatttt 6660

ggtgccaaaa caaactccca ttgacgtcaa tggggtggag acttggaaat ccccgtgagt 6720

caaaccgcta tccacgccca ttgatgtact gccaaaaccg catcaccatg gtaatagcga 6780

tgactaatac gtagatgtac tgccaagtag gaaagtccca taaggtcatg tactgggcat 6840

aatgccaggc gggccattta ccgtcattga cgtcaatagg gggcgtactt ggcatatgat 6900

acacttgatg tactgccaag tgggcagttt accgtaaata ctccacccat tgacgtcaat 6960

ggaaagtccc tattggcgtt actatgggaa catacgtcat tattgacgtc aatgggcggg 7020

ggtcgttggg cggtcagcca ggcgggccat ttaccgtaag ttatgtaacg cggaactcca 7080

tatatgggct atgaactaat gaccccgtaa ttgattacta ttaataacta gtcaataatc 7140

aatgtcaacg cgtatatctg gcccgtacat cgcgaagcag cgcaaaacgc ctaaccctaa 7200

gcagattctt catgcaattg tcggtcaagc cttgccttgt tgtagcttaa attttgctcg 7260

cgcactactc agcgacctcc aacacacaag cagggagcag atactggctt aactatgcgg 7320

catcagagca gattgtactg agagtgcacc ataggggatc gggagatctc ccgatccgtc 7380

gacgtcaggt ggcacttttc ggggaaatgt gcgcggaacc cctatttgtt tatttttcta 7440

aatacattca aatatgtatc cgctcatgag acaataaccc tgataaatgc ttcaataata 7500

ttgaaaaagg aagagtatga gtattcaaca tttccgtgtc gcccttattc ccttttttgc 7560

ggcattttgc cttcctgttt ttgctcaccc agaaacgctg gtgaaagtaa aagatgctga 7620

agatcagttg ggtgcacgag tgggttacat cgaactggat ctcaacagcg gtaagatcct 7680

tgagagtttt cgccccgaag aacgttttcc aatgatgagc acttttaaag ttctgctatg 7740

tggcgcggta ttatcccgta ttgacgccgg gcaagagcaa ctcggtcgcc gcatacacta 7800

ttctcagaat gacttggttg agtactcacc agtcacagaa aagcatctta cggatggcat 7860

gacagtaaga gaattatgca gtgctgccat aaccatgagt gataacactg cggccaactt 7920

acttctgaca acgatcggag gaccgaagga gctaaccgct tttttgcaca acatggggga 7980

tcatgtaact cgccttgatc gttgggaacc ggagctgaat gaagccatac caaacgacga 8040

gcgtgacacc acgatgcctg tagcaatggc aacaacgttg cgcaaactat taactggcga 8100

actacttact ctagcttccc ggcaacaatt aatagactgg atggaggcgg ataaagttgc 8160

aggaccactt ctgcgctcgg cccttccggc tggctggttt attgctgata aatctggagc 8220

cggtgagcgt gggtctcgcg gtatcattgc agcactgggg ccagatggta agccctcccg 8280

tatcgtagtt atctacacga cggggagtca ggcaactatg gatgaacgaa atagacagat 8340

cgctgagata ggtgcctcac tgattaagca ttggtaactg tcagaccaag tttactcata 8400

tatactttag attgatttaa aacttcattt ttaatttaaa aggatctagg tgaagatcct 8460

ttttgataat ctcatgacca aaatccctta acgtgagttt tcgttccact gagcgtcaga 8520

ccccgtagaa aagatcaaag gatcttcttg agatcctttt tttctgcgcg taatctgctg 8580

cttgcaaaca aaaaaaccac cgctaccagc ggtggtttgt ttgccggatc aagagctacc 8640

aactcttttt ccgaaggtaa ctggcttcag cagagcgcag ataccaaata ctgttcttct 8700

agtgtagccg tagttaggcc accacttcaa gaactctgta gcaccgccta catacctcgc 8760

tctgctaatc ctgttaccag tggctgctgc cagtggcgat aagtcgtgtc ttaccgggtt 8820

ggactcaaga cgatagttac cggataaggc gcagcggtcg ggctgaacgg ggggttcgtg 8880

cacacagccc agcttggagc gaacgaccta caccgaactg agatacctac agcgtgagct 8940

atgagaaagc gccacgcttc ccgaagggag aaaggcggac aggtatccgg taagcggcag 9000

ggtcggaaca ggagagcgca cgagggagct tccaggggga aacgcctggt atctttatag 9060

tcctgtcggg tttcgccacc tctgacttga gcgtcgattt ttgtgatgct cgtcaggggg 9120

gcggagccta tggaaaaacg ccagcaacgc ggccttttta cggttcctgg ccttttgctg 9180

gccttttgct cacatgttct ttcctgcgtt atcccctgat tctgtggata accgtattac 9240

cgcctttgag tgagctgata ccgctcgccg cagccgaacg accgagcgca gcgagtcagt 9300

gagcgaggaa gcggaag 9317

<210> 7

<211> 22

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 7

ggcaagcgac ccagcaagaa cc 22

<210> 8

<211> 22

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 8

tgcaggctgc caggaaactt cg 22

<210> 9

<211> 17

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 9

gtaaaacgac ggccagt 17

<210> 10

<211> 17

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 10

caggaaacag ctatgac 17

<210> 11

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 11

accgcgtggt gtataaacag tacg 24

<210> 12

<211> 23

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 12

aaacgtactg tttatacacc acg 23

<210> 13

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 13

accggtataa acagtacgag gaca 24

<210> 14

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 14

aaactgtcct cgtactgttt atac 24

<210> 15

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 15

accgacagta cgaggacatg gtcg 24

<210> 16

<211> 24

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 16

aaaccgacca tgtcctcgta ctgt 24

<210> 17

<211> 34

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 17

caacgtggtg tataaacagt acgaggacat ggtc 34

<210> 18

<211> 35

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 18

caacgtggtg tataaacagt tacgaggaca tggtc 35

<210> 19

<211> 25

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 19

caacgtggtg tataaacagt tggtc 25

<210> 20

<211> 32

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 20

caacgtggtg tataaacagt gaggacatgg tc 32

<210> 21

<211> 10

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 21

caacgtggtc 10

<210> 22

<211> 26

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 22

caacgtggtg ttacgaggac atggtc 26

<210> 23

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 23

c 1

<210> 24

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 24

t 1

<210> 25

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 25

a 1

<210> 26

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 26

g 1

<210> 27

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 27

c 1

<210> 28

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 28

a 1

<210> 29

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 29

c 1

<210> 30

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 30

t 1

<210> 31

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 31

g 1

<210> 32

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 32

c 1

<210> 33

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 33

g 1

<210> 34

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 34

a 1

<210> 35

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 35

g 1

<210> 36

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 36

c 1

<210> 37

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 37

c 1

<210> 38

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 38

t 1

<210> 39

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 39

g 1

<210> 40

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 40

a 1

<210> 41

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 41

c 1

<210> 42

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 42

g 1

<210> 43

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 43

c 1

<210> 44

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 44

t 1

<210> 45

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 45

c 1

<210> 46

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 46

t 1

<210> 47

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 47

g 1

<210> 48

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 48

t 1

<210> 49

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 49

g 1

<210> 50

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 50

a 1

<210> 51

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 51

c 1

<210> 52

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 52

t 1

<210> 53

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 53

t 1

<210> 54

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 54

a 1

<210> 55

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 55

c 1

<210> 56

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 56

g 1

<210> 57

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 57

t 1

<210> 58

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 58

c 1

<210> 59

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 59

c 1

<210> 60

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 60

a 1

<210> 61

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 61

c 1

<210> 62

<211> 1

<212> DNA

<213> Artificial Sequence (Artificial Sequence)

<400> 62

g 1

Claims

1. A sgRNA targeting nucleotide fragment of a specific targeting mouse Gdf5 gene is characterized in that the nucleotide sequence corresponding to the sgRNA is a sequence shown in SEQ ID NO. 1.

2. A method for editing a mouse Gdf5 gene by using the sgRNA targeting sequence specifically targeting the mouse Gdf5 gene of claim 1, comprising the steps of:

step 1: synthesizing a forward oligonucleotide sequence by adding accg to the 5' end of the sgRNA guide sequence of the specific targeting mouse Gdf5 gene of claim 1;

meanwhile, according to the sgRNA guide sequence of the specific targeting mouse Gdf5 gene of claim 1, obtaining the corresponding DNA complementary strand, and adding aaac to the 5' end of the DNA complementary strand to synthesize a reverse oligonucleotide sequence;

annealing the forward oligonucleotide sequence and the reverse oligonucleotide sequence to form a double-stranded DNA fragment having a sticky end;

step 2: digesting a target vector pGL3-U6-sgRNA plasmid shown as SEQ ID No.4 by using Bsa I restriction enzyme to obtain a digestion product pGL3-U6-sgRNA-Bsa I;

and step 3: connecting the double-stranded DNA fragment with the sticky end obtained in the step 1 with the enzyme digestion product pGL3-U6-sgRNA-Bsa I obtained in the step 2, converting the connection product into competent escherichia coli, coating the competent escherichia coli on an ampicillin-resistant LB culture medium, culturing overnight at 37 ℃ for 20h, selecting a single clone, identifying a positive clone by sequencing with a universal primer U6 shown in SEQ ID No.5, shaking the positive clone, and extracting a plasmid to obtain pGL3-U6-Gdf5-sgRNA plasmid;

and 4, step 4: co-transfecting mouse N2a cells with the pGL3-U6-Gdf5-sgRNA plasmid obtained in the step 3 and the pST1374-NLS-flag-l inker-Cas9 expression plasmid shown in SEQ ID NO.6, and obtaining positive sgRNA-Cas9 co-transfected cells after drug screening;

and 5: carrying out cell lysis on the positive sgRNA-Cas9 cotransfected cells obtained in the step (4), carrying out PCR amplification reaction on the DNA of the targeting site by taking the obtained cell lysis solution as a template, taking the PCR amplification product of the DNA of the targeting site to carry out Sanger sequencing, and if the targeting site has a set peak, primarily confirming that gene editing occurs;

3. The method for editing mouse Gdf5 gene according to claim 2, wherein in step 1, the annealing reaction system is specifically: 10 μ M forward oligonucleotide, 5 μ L; 10 μ M reverse oligonucleotide, 5 μ L; 10 XT 7 Endonuclease I buffer, 2. mu.L; ddH₂O, 8 mu L; the reaction procedure is specifically as follows: 95 ℃ for 5 min; 95 ℃ to 85 ℃, and-1 ℃/cycle, for 10 cycles; from 85 ℃ to 25 ℃,-0.1 ℃/cycle for 600 cycles, and the annealed product is stored at-20 ℃.

4. The method for editing mouse Gdf5 gene according to claim 2, wherein in the step 2, the enzyme digestion reaction system specifically comprises: pGL3-U6-sgRNA plasmid, 2. mu.g; 10 Xenzyme digestion buffer, 2 uL; bsa I restriction enzyme, 2. mu.L; supplemental ddH₂And O, setting the enzyme digestion reaction system at 37 ℃ for reaction for 3h until the total volume is 20 mu L.

5. The method for editing mouse Gdf5 gene according to claim 2, wherein the specific method for transforming competent Escherichia coli in step 3 is as follows: adding 5 μ L of the ligation product into 30 μ L of competent Escherichia coli, mixing, standing on ice for 25min, performing water bath heat shock at 42 deg.C for 90s, cooling on ice for 2min, adding 150 μ L of LB liquid culture medium at 220 rpm and 37 deg.C for 30min, and coating on the surface of LB liquid culture medium containing ampicillin resistance; in the LB culture medium containing ampicillin resistance, the concentration of ampicillin is 50 mug/mL; the temperature of the shake bacteria is 37 ℃, the rotating speed is 220 r/min, and the shake bacteria is inverted and cultured overnight after being coated on a culture medium; the extraction plasmid adopts a kit for extracting endotoxin-removing plasmid.

6. The method for editing mouse Gdf5 gene, according to claim 2, wherein in the step 4, the drugs are puromycin with a concentration of 50 μ g/ml and blasticidin with a concentration of 100 μ g/ml; the mouse N2a cells were inoculated and cultured in DMEM complete medium containing 10% v/v fetal calf serum at 37 ℃ and 5% CO before transfection₂Culturing in an incubator, replacing fresh culture medium every 2d-3d, digesting with 0.25% trypsin after the cell confluence reaches 80-90%, then passing through a 6-well plate, and transfecting after 18-20 h and when the cell confluence reaches 60-70%.

7. The method for editing mouse Gdf5 gene according to claim 2, wherein the PCR amplification reaction of the DNA at the target site in step 5 comprises: 2 mu L of cell lysate, 1 mu L of upstream primer, 1 mu L of downstream primer, 2 mu L of dNTP mix, 1 mu L of TaKaRa Ex Taq, 2.5 mu L of 10 XEx Taq Buffer and 25 mu L of sterilized water; the PCR amplification reaction of the target site DNA is carried out by the following procedures: 95 ℃ for 5 min; 35 cycles of 95 ℃, 20s, 57 ℃, 20s, 72 ℃, 25 s; 72 ℃, 5min, 16 ℃, infinity.

8. The method for editing mouse Gdf5 gene according to claim 7, wherein the sequence of the upstream primer is shown in SEQ ID No. 7; the sequence of the downstream primer is shown as SEQ ID NO. 8.

9. The method for editing mouse Gdf5 gene according to claim 2, wherein in step 6, the TA clone sequencing specifically comprises: performing gel recovery and purification on the PCR amplification product of the targeted site obtained in the step 5, and connecting the purified DNA to a plasmid vector to obtain a connection product; and transforming the ligation products into competent escherichia coli, coating the competent escherichia coli on an LB (lysogeny broth) culture medium with aminobenzyl resistance, performing overnight culture at 37 ℃ for 20 hours, performing colony PCR (polymerase chain reaction) reaction verification, screening positive clones, and performing Sanger sequencing on the positive clones.

10. The method for editing mouse Gdf5 gene according to claim 9, wherein the linked reaction system is: PCR purified product 40ng, Solution I2.5. mu.L and PMD19 carrier 0.5. mu.L, and water is added to make up to 5. mu.L; the specific method for transforming the competent escherichia coli comprises the following steps: adding 5 μ L of the ligation product into 30 μ L of competent Escherichia coli, mixing, standing on ice for 25min, performing water bath heat shock at 42 deg.C for 90s, cooling on ice for 2min, adding 150 μ L of LB liquid culture medium at 220 rpm, activating at 37 deg.C for 30min, and coating on the surface of LB liquid culture medium with ampicillin resistance; in the LB culture medium with ampicillin resistance, the concentration of ampicillin is 50 mug/mL; the colony PCR reaction system comprises: 1 mu L of colony aqueous solution, 5 mu L of Premix Taq enzyme, 0.5 mu L of upstream primer, 0.5 mu L of downstream primer and 3 mu L of sterilized water; the procedure of the colony PCR reaction was: 95 ℃ for 5 min; 95 ℃, 20s, 60 ℃, 20s, 72 ℃, 25s, 26 cycles; 72 ℃ for 5 min; the sequence of the upstream primer is shown as SEQ ID NO. 9; the sequence of the downstream primer is shown as SEQ ID NO. 10.