OBJECTIVE: To construct a mouse model of breast-specific modification of three genes of BRCA1, BRCA2 and CDH1 by CRISPR/Cas9 system.
METHODS: sgRNAs were designed and synthesized for mouse BRCA1, BRCA2 and CDH1 genes, respectively, and a pX330-spCas9-U6-gRNA co-expression vector was constructed. The CBh promoter in the co-expression vector was replaced with a breast tissue-specific promoter WAP. Transgenic mice were prepared by pronuclear injection of fertilized eggs.
Results: A total of 190 fertilized eggs were injected, 130 active fertilized eggs were obtained, and 4 recipient mice were transplanted. 42 F0 offspring were produced, and 11 transgenic positive mice were identified, with a positive rate of 26.19%. The F0 generation was positive After the mice were bred, 39 F1 offspring mice were obtained, of which 9 were F1 transgenic positive mice.
Conclusion: The transgenic positive mice were successfully prepared by constructing the mammary tissue-specific expression Cas9 vector.