Programmable Base Editing of the Sheep Genome Revealed No Genome-Wide Off-Target Mutations

Frontiers in Genetics

Yao Liu¹  Xiaolong Wang¹  Shiwei Zhou¹  Chong He¹  Xiaoe Zhao¹  Chao Li¹  Qifang Kou¹  Bjoern Petersen¹  Qiang Ding²  Baohua Ma³  Tad Sonstegard⁴  Guanwei Li⁴  Wenzhi Niu⁴  Yige Ding⁴  Yulin Chen⁴  Jiao Liu⁴  Bei Cai⁴  Ying Wang⁴  Honghao Yu⁴ 

[1] College of Animal Science and Technology, Northwest A&;College of Information Engineering, Northwest A&;College of Veterinary Medicine, Northwest A&F University, Yangling, China;

关键词: base editing;    genome editing;    point mutation;    whole genome sequencing;    off-target mutation;   

DOI  :  10.3389/fgene.2019.00215

来源: DOAJ

【 摘 要 】

Since its emergence, CRISPR/Cas9-mediated base editors (BEs) with cytosine deaminase activity have been used to precisely and efficiently introduce single-base mutations in genomes, including those of human cells, mice, and crop species. Most production traits in livestock are induced by point mutations, and genome editing using BEs without homology-directed repair of double-strand breaks can directly alter single nucleotides. The p.96R > C variant of Suppressor cytokine signaling 2 (SOCS2) has profound effects on body weight, body size, and milk production in sheep. In the present study, we successfully obtained lambs with defined point mutations resulting in a p.96R > C substitution in SOCS2 by the co-injection of BE3 mRNA and a single guide RNA (sgRNA) into sheep zygotes. The observed efficiency of the single nucleotide exchange in newborn animals was as high as 25%. Observations of body size and body weight in the edited group showed that gene modification contributes to enhanced growth traits in sheep. Moreover, targeted deep sequencing and unbiased family trio-based whole genome sequencing revealed undetectable off-target mutations in the edited animals. This study demonstrates the potential for the application of BE-mediated point mutations in large animals for the improvement of production traits in livestock species.

【 授权许可】

Unknown