Study On The Biological Characteristics Of NIH Hair-mutant Mice And Construction Of Hr Gene Knockout Mice

Spontaneous gene mutations are an important way to obtain new mouse models.Due to the lack of human factors,the process of mutational disease in spontaneously mutant mouse models is closer to that of the corresponding human disease,so the spontaneous gene mutation mouse model is very suitable for the study of related human diseases.The NIH mouse is a closed group of mouse species derived from Swiss mice,and the same source has ICR,KM mice.NIH hair-mutated mice are spontaneous mutant mice found in the laboratory during the breeding of NIH mice.The phenotypes currently found are mainly sparse hair and no beard.There was a long-term abnormality in the first hair after birth,and there was a significant difference in phenotype from normal mice after 7 days of birth.In normal mice,the coat is gradually thick and the white hair is completely covered;while the hair-mutated mouse still shows a naked body.As time progressed,hair-mutated mice developed a hairless-hairy-hairless phenotypic change.In the middle and late stages of the growth phase of the second hair growth cycle at 5-6 weeks of age,the two mice exhibited a maximization of phenotypic differences.The mouse has a thymus that can be raised in a barrier environment;spontaneous tumors can occur in the later stages;immune levels change.Since the discovery of this mutant mouse in 2007,a new line of mutant phenotype stable genetic experimental animals has been established through more than 10 years of inbreeding.In this study,the phenotype and biological characteristics of the mutant mouse population were analyzed by establishing the inbred strain population of the hairmutated mice.Then,the whole genome resequencing technique was used to analyze the genomic information of the mutant mouse,and the SNP site was passed.Correlation analysis between the Indel locus and the coat mutant phenotype,the correlation between the Hr gene and the coat mutant phenotype,and the knockout of the Hr gene exon3-7 by the CRISPR/Cas9 technology to obtain the F0 generation chimeric mouse.After mating with normal C57 mice,F1 heterozygotes were obtained,and a population of stably inherited Hr knockout mice was established.the result shows:1.The NIH mouse hair mutation is a mutation controlled by a recessive gene.Compared with normal mice,the liver,spleen,lung,left kidney,thymus,ovary and uterus coefficients of female mice with hair-mutated populations were significantly different;male mice heart,lung,left and right kidney,thymus and seminal vesicles There are significant differences in the coefficients.Serum aminotransferase(ALT and AST),uric acid and triglyceride(TG)were elevated in the hair-mutated mice,and the difference was significant.The red blood cells,hemoglobin,hematocrit,LY lymphocytes and their proportions in the mutant mice were significantly decreased(p < 0.05);the mutated mouse CD3+CD4+/CD3+CD8+ before and after infection with Listeria.The ratio was significantly lower than that of normal mice(p < 0.05).2.The results of tolerance test and tumor-bearing experiment showed that the hairmutated mice were suitable for drug metabolism research related to glucose metabolism and tumor.NIH hair-mutant mice have enhanced learning and memory ability and can be used for drug screening studies of related neurocognition.3.There were 991,844 SNP loci in the hair-mutated mice and normal mice.The highest correlation SNP interval contained 345 genes,involving 47 biological pathways;there were 341,082 Small In Del loci,and the highest associated Small In Del.The interval contains 518 genes and involves 55 biological pathways.5.For the first time,using the CRISPR/Cas9 technology,F0 generation chimeric mice with a large fragment of exon3-7 knockdown of Hr gene were obtained,and the coat phenotype was hairless.6.F1 generation heterozygous mouse populations were obtained by mating F0 generation chimeric mice with normal C57 mice.The F1 generation heterozygous mouse positive rate was 14.3%.In summary,this study analyzed the phenotype and biological characteristics of the hair-mutated mouse population,and analyzed the correlation between the Hr gene and the hair-mutated phenotype at the genome level,and obtained the large fragment knockout of the Hr gene.F0 generation chimeric mice and F1 heterozygous mice provide a theoretical basis for further analysis of the biological mechanism of the hair-mutated phenotype.