Shan Huanhuan, Liu Zhiquan, Jia Yingqi, Chen Siyu, Chen Mao, Song Yuning, Sui Tingting, Lai Liangxue, Li Zhanjun
Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun 130062, China.
CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
Mol Ther Nucleic Acids. 2021 May 19;25:168-172. doi: 10.1016/j.omtn.2021.05.012. eCollection 2021 Sep 3.
Recently, a rationally engineered SpCas9 variant (SpCas9-NG) that can recognize a minimal NG protospacer adjacent motif (PAM) was reported to expand the targeting scope in genome editing. However, increased genome-wide off-target mutations with this variant compared with SpCas9 were reported in previous studies. In addition, lower base editing frequencies and higher unintended off-target mutations were also found in -ablated rabbits generated by NG-BE4max in our study. Here, a high-fidelity base editor, NG-HiFi, in comparison to NG-BE4max, showed retention of on-target activity while exhibiting significantly decreased off-target activity in -ablated rabbits. Collectively, the improved specificity and reduced off-target effect of SpCas9-NG assisted in cytidine base editing with the NG-HiFi system, providing a promising tool to precisely model human diseases in rabbits.
最近，据报道，一种经过合理设计的SpCas9变体（SpCas9-NG）能够识别最小的NG原间隔相邻基序（PAM），从而扩大了基因组编辑中的靶向范围。然而，在先前的研究中，与SpCas9相比，该变体导致全基因组脱靶突变增加。此外，在我们的研究中，通过NG-BE4max产生的基因敲除兔中也发现了较低的碱基编辑频率和较高的意外脱靶突变。在这里，与NG-BE4max相比，一种高保真碱基编辑器NG-HiFi在基因敲除兔中显示出保留了靶向活性，同时脱靶活性显著降低。总体而言，SpCas9-NG提高的特异性和降低的脱靶效应有助于利用NG-HiFi系统进行胞嘧啶碱基编辑，为在兔中精确模拟人类疾病提供了一个有前景的工具。
