42results about How to "Efficient knockout" patented technology

The invention discloses a CRISPR-Cas9 system for knocking out the gene GRIN2D and its application. The CRISPR-Cas9 system comprises Cas9 and gRNA specifically targeting to the gene GRIN2D. The invention also discloses application of the CRISPR-Cas9 system to preparation of drugs used for treating cancer and application of the gene GRIN2D to diagnostic kits and medicines used for precise treatmentof stomach cancer and other tumors. In virtue of a clinical sample tissue chip of stomach cancer, the gene GRIN2D is proved to be increased in expression in stomach cancer tissue and be related to prognosis according to immunohistochemical results. The CRISPR-Cas9 system provided by the invention can highly efficiently knock out the highly-expressed gene GRIN2D in stomach cancer and inhibit the proliferation and migration/invasion of gastric cancer cells, and is simple to operate and high in knockout efficiency. The CRISPR-Cas9 system is expected to be applied to diagnosis and treatment of stomach cancer and other tumors with over-expressed GRIN2D. The CRISPR-Cas9 system is applicable to a plurality of tumors with abnormal expression of GRIN2D.

The invention discloses an unmarked gene knock-out method of extremely acidophilic thiobacillus ferrooxidans based on the principle of homologous recombination. The method comprises the following steps of: constructing initial plasmids, suicide plasmids containing homologous fragments at upstream and downstream parts of target genes to be knocked out, and induction plasmids containing yeast endonuclease I-SceI genes; jointing and transferring the suicide plasmids and the induction plasmids to acidophilic thiobacillus ferrooxidans; and screening and identifying single commutators generating homologous recombination for the first time and double-exchange mutant strains generating homologous recombination for the second time. The method disclosed by the invention realizes the unmarked gene knock-out of acidophilic thiobacillus ferrooxidans for the first time, can realize the purpose of quickly, stably and efficiently knocking out the genes of the thiobacillus ferrooxidans, and can be used for researching the functional and metabolic mechanisms of the genes of the thiobacillus ferrooxidans, improving the genetic characters and constructing efficient bioleaching engineering bacteria; and moreover, the obtained mutant strain does not carry any resistance gene, thus the obtained mutant strain not only can be used as an original strain to knock out and improve genes in subsequent different sites, but also can be safely used for large-scale industrial production.

The invention provides sgRNA or PTG (Polycistronic tRNA-gRNA), through combination with a CRISPR-Cas9 technique, a T cell antigen receptor (TCR) can be knocked out, or one or more of genes relevant tomajor histocompatibility complex (MHCI) and immunosuppression molecules can be knocked out. The invention also provides a general type CAR-T cell which can express chimeric antigen receptor (CAR) butcannot express TCR, and a preparation method of the general type CAR-T cell. The general type CAR-T cell prepared by the preparation method is suitable for heterogeneity antigen, has generality and has higher killability at the same time.

The invention discloses a pig muscle myostatin gene editing site 864-883 in a pig genome and application thereof, and belongs to the field of biological engineering. One gene editing target site is separated out from a pig muscle myostatin gene region; the sequence of the target site is 5'-GGATTTTGAAGCTTTTGGATGGG-3'; the site is positioned at a No.3 exon of an MSTN (myostatin) editing region. The site can be specifically identified by Cas9 endonuclease, so that mediated double chains fracture and then generate homologous recombination with targeting vectors; mutant genes or selectable maker gene and the like are integrated to the preset sites of a recipient cell genome. Statistical results show that the site targeting efficiency is 86.7 percent. The pig muscle myostatin gene editing site provided by the invention has the advantages that the effective target is provided for the precise embedding of the gene; new strategies are provided for developing live pig new varieties with high meat factor; reliable means and materials can be provided for developing myostatin molecular mechanisms and signal channels.

The invention discloses sgRNA used for targeted knockout of a human NKG2A/KLRC1 gene, and belongs to the technical field of genetic engineering. The sgRNA has an arbitrary nucleotide sequence as shownin SEQ ID NO.1-56. The invention further discloses a sgRNA compound, expression vector, CRISPR/Cas9 system and kit used for targeted knockout of the human NKG2A/KLRC1 gene, and application of the sgRNA compound in preparing an immune cell medicine for treating neoplastic diseases. By means of the prepared specific targeted human KNG2A/KLRC1 gene, the human NKG2A/KLRC1 gene can be precisely targeted, effective knockout can be achieved, and meanwhile, an obtained human NKG2A/KLRC1 gene knockout immune cell is suitable for multiple tumor cell models; and a preparation method has simple steps, the targeting specificity of the sgRNA is good, and the knockout efficiency of the CRISPR/Cas9 system is high.

The invention discloses a method for screening an unmarked gene knockout bacterial strain of acidithiobacillus thiooxidans. The method comprises introducing a knockout plasmid for construction of a target gene and an induction plasmid carrying an I-SceI gene into acidithiobacillus thiooxidans by conjugational transfer, carrying out single recon screening by a resistance maker, and carrying out double recon preliminary screening by blue-white selection. The method discloses the method for unmarked gene knockout of acidithiobacillus thiooxidans first, utilizes beta-galactosidase blue-white selection for double recon screening, can fast, stably and efficiently knock out a target gene, solves the problem that in the existing unmarked gene knockout process, selective pressure lacks so that screening is difficult, shortens double recon screening time, improves screening efficiency, reduces a screening cost and provides a novel method for stable genetic modification of acidithiobacillus thiooxidans.

The invention provides a method for terminating lncRNA diallele transcription. The method comprises the following steps of 1) constructing CMV-antibiotic screening gene-PolyA DNA fragments containing two different antibiotic screening genes; 2) designing gRNA according to different target genes, and constructing Cas9/gRNA expression vectors; 3) inserting the CMV-antibiotic screening gene-PolyA DNA fragments obtained in the step 1) into the target genes, and constructing homologous recombinant vectors containing the target genes; 4) introducing cells: co-transfecting the pair of homologous recombinant vectors containing the target genes obtained in the step 3) and the Cas9/gRNA expression vectors containing the target genes obtained in the step 2) to the cells; and 5) performing screening for at least 2 weeks by using related antibiotics used in the step 1), and obtaining polyclonal cell strains of which lncRNA dialleles are knocked out. According to the method, the purpose of quickly obtaining the cell strains of which the lncRNA dialleles are knocked out at the same time while realizing efficient fixed-point insertion can be achieved.

The invention relates to the technical field of biology and in particular discloses a method for knocking out a saccharomyces cerevisiae chromosome. According to the method, a Vika/vox technology is utilized for removing a complete yeast chromosome, and chromosome centromeres are specifically recombined into a ring by virtue of loci, so that knockout of the whole chromosome is realized. Compared with a method for realizing elimination of the whole chromosome in a reduction mitosis manner, the method disclosed by the invention has the advantages that cutting of the saccharomyces cerevisiae chromosome is more simply, efficiently and rapidly realized, crossing over of sister chromatids is avoided, and a saccharomyces cerevisiae homozygous diploid bacterial strain with the chromosome knocked out is obtained.

The invention discloses a spc-PcopA-yoeBVp gene cassette and a preparation method thereof, and belongs to the technical field of gene engineering, and the spc-PcopA-yoeBVp gene cassette comprises a positive selection marker spc and a negative selection marker PcopA-yoeBVp. The negative selection marker expresses YoeBVp toxin under the induction of copper sulfate and can inhibit the growth of an intermediate strain. By utilizing the gene box, the streptococcus suis traceless gene knockout can be efficiently realized. The gene knockout mutant strain does not contain any resistance marker, so that the polar effect caused by the resistance marker is avoided. In addition, because the gene knockout mutant strain does not contain a resistance marker, the gene knockout mutant strain can be used for subsequent vaccine research.

The invention provides a method for enhancing streptomyces genome editing efficiency and application of the method. By adding an element for controlling Cas9 activity, triple control of Cas9 protein activity on transcription, translation and protein levels is realized, cytotoxicity of Cas9 protein to streptomycete is inhibited, transformation efficiency of plasmids in streptomycete is improved, and efficient gene editing can be realized under induction conditions. According to the invention, a gene editing system which is induced by chemical small molecules and regulated and controlled by inhibitory proteins is established, in-vivo toxicity of Cas9 is inhibited, and efficient introduction of genetic elements and efficient editing of subsequent genes are realized on the premise of not influencing transformation efficiency of editing plasmids and growth and metabolism of host cells. The small molecule chemical inducer is convenient to add, and efficient and accurate genome editing based on double-strand breakage and directional repair can be achieved. The method of the inventioon can be applied to gene engineering and genetic modification transformation of streptomycetes including mode or industrial streptomycetes.

The invention provides sgRNA for knocking out a rice OsPLS4 gene. An sgRNA sequence based on CRISPR/Cas9 is designed for the rice OsPLS4 gene, a DNA fragment containing the coded sgRNA sequence is connected to a carrier carrying the CRISPR/Cas9, rice calluses are transformed with an agrobacterium-mediated method, and the rice OsPLS4 gene is knocked out through screening and identification, whereinthe nucleotide sequence of the sgRNA action site is as shown in SEQ ID NO. 1. The rice endogenous gene OsPLS4 is edited through a CRISPR-CAS9 technology, and an OsPLS4 knockout mutant is obtained. The sgRNA prepared by the invention can efficiently, quickly and accurately target the rice OsPLS4 gene, and has certain significance in fundamental research (rice premature senility molecular mechanism) and production practice (rice premature senility variety improvement and stress-resistant breeding).

The invention provides a method for efficiently and specifically removing plasmids in bacteria by utilizing an integrated suicide vector. The method comprises the following steps: (1) constructing theintegrated suicide vector targeting to-be-knocked-out plasmids, (2) screening and converting the integrated suicide vector, (3) carrying out first-round screening on the bacteria, and (4) carrying out second-round screening on the bacteria. According to the method for efficiently and specifically removing the plasmids in the bacteria by utilizing the integrated suicide vector, the stability of genomes of the bacteria is not influenced, the method is verified in various strains, the plasmids with the sizes of 24kbp to 340kbp can be efficiently knocked out, the method is simple and effective, and the removal rate is as high as 100 percent.