Development of a tau-V337M mouse model using CRISPR/Cas9 system and enhanced ssODN-mediated recombination / 生物工程学报

The generation of a tau-V337M point mutation mouse model using gene editing technology can provide an animal model with fast disease progression and more severe symptoms, which facilitate the study of pathogenesis and treatment of Alzheimer's disease (AD). In this study, single guide RNAs (sgRNA) and single-stranded oligonucleotides (ssODN) were designed and synthesized in vitro. The mixture of sgRNA, Cas9 protein and ssODN was microinjected into the zygotes of C57BL/6J mice. After DNA cutting and recombination, the site homologous to human 337 valine (GTG) in exon 11 was mutated into methionine (ATG). In order to improve the efficiency of recombination, a Rad51 protein was added. The female mice mated with the nonvasectomy male mice were used as the surrogates. Subsequently, the 2-cell stage gene edited embryos were transferred into the unilateral oviduct, and the F0 tau-V337M mutation mice were obtained. Higher mutation efficiency could be obtained by adding Rad51 protein. The F0 tau-V337M point mutation mice can pass the mutation on to the F1 generation mice. In conclusion, this study successfully established the first tau-V337M mutation mouse by using Cas9, ssODN and Rad51. These results provide a new method for developing AD mice model which can be used in further research on the pathogenesis and treatment of AD.

RNAi-mediated Stable Silencing of HGPRT Expression in Rabbit Fibroblasts and SCNT Embryo Production / 生物化学与生物物理进展

The hypoxanthine-guanine phosphoribosyl transferase (HGPRT) gene mutation is responsible for gouty arthritis, kidney stone, and Lesch-Nyhan Syndrome (LNS). It has been reported that the expression of HGPRT is decreased or even absent in these diseases. Rabbits are an ideal model for studying the pathology of these diseases. Therefore, the development of an HGPRT-knockdown rabbit model will be highly beneficial m such studies. Stable HGPRT-knoekdown transgenie fibroblast lines were generated by transfecting rabbit fibroblasts with RNA interference (RNAi) plasmids. Polymerase chain reaction (PCR) analyses indicated that the average positive rate was 83.3%. The mRNA and protein levels of HGPRT in the transgenic fibroblast lines were significantly lower than that in the control. Transgenic rabbit blastocysts were derived after performing nuclear transfer. The results show that RNAi can be used to stably knock down expression of the HGPRT in rabbit fibroblasts and further improvements in related technologies will facilitate the use of this method for the generation of HGPRT-knockdown rabbits.