Effective gene editing by high-fidelity base editor 2 in mouse zygotes  

作　　者：Puping Liang Hongwei Sun Ying Sun Xiya Zhang Xiaowei Xie Jinran Zhang zhen Zhang Yuxi Chen Chenhui Ding Yuanyan Xiong Wenbin Ma Dan Liu Junjiu Huang Zhou Songyang 

机构地区：[1]Key Laboratory of Gene Engineering of the Ministry of Education, Guangzhou Key Laboratory of Healthy Aging Researchand State Key Laboratory of Biocontrol, SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University,Guangzhou 510275, China [2]State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510275, China [3]Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital,Sun Yat-sen University, Guangzhou 510275, China [4]Guangzhou Magigen Biotechnology Co.Ltd, Guangzhou 510320, China [5]5 Vernaand Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA

出　　处：《Protein & Cell》2017年第8期601-611,共11页蛋白质与细胞（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China （Grant Nos. 91640119, 31601196, 81330055, 31371508, and 31671540）, the Natural Science Foundation of Guangdong Province （2016A030310206 and 2014A030312011）, the Science and Technology Planning Project of Guangdong Province （2015B020228002 and 2015A020212005）, the Guangzhou Science and Technology Project （201605030012 and 201707010085）, and the Fundamental Research Funds for the Central Universities （161gzd13 and 161gpy31）. We would also like to acknowledge the support of CA211653, CPRIT RP160462, the Welch Foundation Q-1673, and the C-BASS Shared Resource at the Dan L. Duncan Cancer Center （DLDCC） of Baylor College of Medicine （P30CA125123）.

摘　　要：Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease- causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical applicaUon of such approaches. Recently, a base editor （BE） system built on cytidine （C） deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine （T） efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high- fidelity version of base editor 2 （HF2-BE2）, and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease- causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical applicaUon of such approaches. Recently, a base editor （BE） system built on cytidine （C） deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine （T） efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high- fidelity version of base editor 2 （HF2-BE2）, and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.

关 键 词：base editor high-fidelity mouse embryos proximal-site deamination whole-genome sequencing 

分 类 号：Q954.4[生物学—动物学] TP316[自动化与计算机技术—计算机软件与理论]