Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, Maryland, 20892, USA.
Genomics Core, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, Maryland, 20892, USA.
Commun Biol. 2020 Jan 9;3(1):19. doi: 10.1038/s42003-019-0745-3.
Deaminase base editing has emerged as a tool to install or correct point mutations in the genomes of living cells in a wide range of organisms. However, the genome-wide off-target effects introduced by base editors in the mammalian genome have been examined in only one study. Here, we have investigated the fidelity of cytosine base editor 4 (BE4) and adenine base editors (ABE) in mouse embryos using unbiased whole-genome sequencing of a family-based trio cohort. The same sgRNA was used for BE4 and ABE. We demonstrate that BE4-edited mice carry an excess of single-nucleotide variants and deletions compared to ABE-edited mice and controls. Therefore, an optimization of cytosine base editors is required to improve its fidelity. While the remarkable fidelity of ABE has implications for a wide range of applications, the occurrence of rare aberrant C-to-T conversions at specific target sites needs to be addressed.
脱氨酶碱基编辑已成为一种在广泛的生物体的活细胞基因组中安装或纠正点突变的工具。然而，在哺乳动物基因组中碱基编辑器引入的全基因组脱靶效应仅在一项研究中进行了检查。在这里，我们使用基于家族的三人队列的无偏全基因组测序，研究了胞嘧啶碱基编辑器 4 (BE4) 和腺嘌呤碱基编辑器 (ABE) 在小鼠胚胎中的保真度。相同的 sgRNA 用于 BE4 和 ABE。我们证明，与 ABE 编辑的小鼠和对照相比，BE4 编辑的小鼠携带更多的单核苷酸变异和缺失。因此，需要对胞嘧啶碱基编辑器进行优化以提高其保真度。虽然 ABE 的显著保真度对广泛的应用具有重要意义，但需要解决特定靶位点罕见的异常 C 到 T 转换的发生。
