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Hypotrichosis simplex (HS) and woolly hair (WH) are rare and monogenic disorders of hair loss. HS, characterized by a diffuse loss of hair, usually begins in early childhood and progresses into adulthood. WH displays strong coiled hair involving a localized area of the scalp or covering the entire side. Mutations in the keratin K71(KRT71) gene have been reported to underlie HS and WH. Here, we report the generation of a mouse model of HS and WH by the co−injection of Cas9 mRNA and sgRNA, targeting exon6 into mouse zygotes. The Krt71−knockout (KO) mice displayed the typical phenotypes, including Krt71 protein expression deletion and curly hair in their full body. Moreover, we found that mice in 3–5 weeks showed a new phenomenon of the complete shedding of hair, which was similar to nude mice. However, we discovered that the mice exhibited no immune deficiency, which was a typical feature of nude mice. To our knowledge, this novel mouse model generated by the CRISPR/Cas9 system mimicked woolly hair and could be valuable for hair disorder studies. [ABSTRACT FROM AUTHOR]

The limb girdle muscular dystrophy type 2L (LGMD2L) is caused by mutations of the ANO5 gene in humans which encodes a 913 amino-acid integral membrane protein. Although cardiomyopathy has been reported in patients with an ANO5 mutation, the ANO5 mutant mice did not recapitulate this phenotype in previous studies. This study demonstrated that the ANO5−/− rabbits recapitulated the typical signs of cardiomyopathy with decreased ejection fraction (EF) and fraction shortening (FS) with increased interstitial fibrosis. This ANO5−/− rabbit model would promote basic research to comprehend the pathogenesis and mechanism of ANO5-related cardiomyopathy. [ABSTRACT FROM AUTHOR]

The CRISPR/Cas9 system is a highly efficient and convenient genome editing tool, which has been widely used for single or multiple gene mutation in a variety of organisms. Disruption of multiple homologous genes, which have similar DNA sequences and gene function, is required for the study of the desired phenotype. In this study, to test whether the CRISPR/Cas9 system works on the mutation of multiple homologous genes, a single guide RNA (sgRNA) targeting three fucosyltransferases encoding genes ( FUT1 , FUT2 and SEC1 ) was designed. As expected, triple gene mutation of FUT1 , FUT2 and SEC1 could be achieved simultaneously via a sgRNA mediated CRISPR/Cas9 system. Besides, significantly reduced serum fucosyltransferases enzymes activity was also determined in those triple gene mutation rabbits. Thus, we provide the first evidence that multiple homologous genes knockout (KO) could be achieved efficiently by a sgRNA mediated CRISPR/Cas9 system in mammals, which could facilitate the genotype to phenotype studies of homologous genes in future. [ABSTRACT FROM AUTHOR]

Tandem repeats have been shown to cause human genetic diseases and contribute significantly to genome variation and instability. Although multi-sgRNAs mediated CRISPR/Cas9 system have used to generate regional deletions previously, in this study we explored a method of generating regional deletions of tandem repeats by taking advantage of the off-target effects of CRISPR/Cas9 in 293FT cells. Our results revealed that generation of large-fragment deletions of tandem repeats located in the MAGEL2 and XIST gene was possible. In summary, we have demonstrated that large-fragment deletions of tandem repeats can be achieved using a sgRNA-directed CRISPR/Cas9 system, facilitating the functional study of tandem repeats in future studies. [ABSTRACT FROM AUTHOR]