小柯机器人

利用TadA变体优化胞嘧啶碱基编辑器（CBE），这一成果由Beam公司Nicole M. Gaudelli课题组经过不懈努力而取得。相关论文于2023年1月9日发表在《自然—生物技术》杂志上。

研究人员研发了一种使用TadA（CBE-T）工程变体的CBE编辑器并描绘了其特征，这些变体可在一组序列多样化的基因组位点中实现高靶向C-G到T-A突变，在原代细胞中显示出强大的活性，并且不会增加全基因组内的突变。

此外，研究人员报道了胞嘧啶和腺嘌呤碱基编辑器（CABE）催化A-to-I和C-to-U编辑（CABE-Ts）。与ABE一起，CBE-T和CABE-T可以使用实验室进化的TadA变体对所有过渡突变进行编程，其相对于先前报道的CBE具有更好的特性。

研究人员表示，胞嘧啶碱基编辑器可实现可编程基因组C-G-to-T-A过渡突变，通常该编辑器包含修饰的CRISPR-Cas酶（一种天然存在的胞苷脱氨酶）和尿嘧啶修复抑制剂。先前的研究表明，利用天然存在的胞苷脱氨酶CBE可能导致无指导的全基因组胞嘧啶脱氨。虽然随后的研究研发了可减少随机全基因组脱靶的改进版CBE，但这些编辑器可能会遭受次优靶向性能的影响。

附：英文原文

Title: Improved cytosine base editors generated from TadA variants

Author: Lam, Dieter K., Feliciano, Patricia R., Arif, Amena, Bohnuud, Tanggis, Fernandez, Thomas P., Gehrke, Jason M., Grayson, Phil, Lee, Kin D., Ortega, Manuel A., Sawyer, Courtney, Schwaegerle, Noah D., Peraro, Leila, Young, Lauren, Lee, Seung-Joo, Ciaramella, Giuseppe, Gaudelli, Nicole M.

Issue&Volume: 2023-01-09

Abstract: Cytosine base editors (CBEs) enable programmable genomic C·G-to-T·A transition mutations and typically comprise a modified CRISPR–Cas enzyme, a naturally occurring cytidine deaminase, and an inhibitor of uracil repair. Previous studies have shown that CBEs utilizing naturally occurring cytidine deaminases may cause unguided, genome-wide cytosine deamination. While improved CBEs that decrease stochastic genome-wide off-targets have subsequently been reported, these editors can suffer from suboptimal on-target performance. Here, we report the generation and characterization of CBEs that use engineered variants of TadA (CBE-T) that enable high on-target C·G to T·A across a sequence-diverse set of genomic loci, demonstrate robust activity in primary cells and cause no detectable elevation in genome-wide mutation. Additionally, we report cytosine and adenine base editors (CABEs) catalyzing both A-to-I and C-to-U editing (CABE-Ts). Together with ABEs, CBE-Ts and CABE-Ts enable the programmable installation of all transition mutations using laboratory-evolved TadA variants with improved properties relative to previously reported CBEs.

DOI: 10.1038/s41587-022-01611-9

Source: https://www.nature.com/articles/s41587-022-01611-9

Nature Biotechnology：《自然—生物技术》，创刊于1996年。隶属于施普林格·自然出版集团，最新IF：68.164
官方网址：https://www.nature.com/nbt/
投稿链接：https://mts-nbt.nature.com/cgi-bin/main.plex