中国科学院高彩霞研究组利用CyDENT对细胞器和核基因组进行链优先碱基编辑。2023年8月28日出版的《自然—生物技术》杂志发表了这项成果。

他们提出CyDENT碱基编辑，一个无CRISPR，链选择性，模块化碱基编辑器。CyDENT包括一对与FokI酶，单链特异性胞苷脱氨酶和外切酶融合的转录激活因子样效应(TALE)，以产生用于脱氨的单链DNA底物。他们在细胞核、线粒体和叶绿体基因组中展示了有效的碱基编辑。在某些线粒体位点，他们显示编辑效率为14%，链特异性为95%。

此外，通过将CyDENT脱氨酶与更倾向于编辑GC基序的酶交换，他们在其他方法无法编辑的位点上展示了高达20%的线粒体碱基编辑。CyDENT的模块化特性为各种应用程序提供了一套定制的基础编辑器。

据了解，基于TALE的工具用于细胞核和细胞器DNA的碱基编辑，依赖于双链DNA脱氨酶，它编辑两条DNA链上的底物碱基，降低了编辑精度。

附：英文原文

Title: Strand-preferred base editing of organellar and nuclear genomes using CyDENT

Author: Hu, Jiacheng, Sun, Yu, Li, Boshu, Liu, Zhen, Wang, Zhiwei, Gao, Qiang, Guo, Mengyue, Liu, Guanwen, Zhao, Kevin Tianmeng, Gao, Caixia

Issue&Volume: 2023-08-28

Abstract: Transcription-activator-like effector (TALE)-based tools for base editing of nuclear and organellar DNA rely on double-stranded DNA deaminases, which edit substrate bases on both strands of DNA, reducing editing precision. Here, we present CyDENT base editing, a CRISPR-free, strand-selective, modular base editor. CyDENT comprises a pair of TALEs fused with a FokI nickase, a single-strand-specific cytidine deaminase and an exonuclease to generate a single-stranded DNA substrate for deamination. We demonstrate effective base editing in nuclear, mitochondrial and chloroplast genomes. At certain mitochondrial sites, we show editing efficiencies of 14% and strand specificity of 95%. Furthermore, by exchanging the CyDENT deaminase with one that prefers editing GC motifs, we demonstrate up to 20% mitochondrial base editing at sites that are otherwise inaccessible to editing by other methods. The modular nature of CyDENT enables a suite of bespoke base editors for various applications.

DOI: 10.1038/s41587-023-01910-9

Source: https://www.nature.com/articles/s41587-023-01910-9