上海科技大学研究团队揭示了利用碱基切除修复对线粒体DNA进行有效的腺嘌呤碱基编辑。相关论文于2025年3月25日发表在《自然—生物技术》杂志上。

在这里，该课题组研究人员揭示了TALEDs介导的A-to-G编辑依赖于通过碱基切除修复（BER）形成的ssDNA区域，这是由双链DNA特异性胞苷脱氨酶（DddA）诱导的C-to-U脱氨引发的。小组用高活性变体DddA6取代DddA，并将人尿嘧啶DNA糖基酶修饰为TadA8e，开发了一系列具有更高编辑效率的增强型TALEDs （eTALED6s）。通过进一步改造TadA8e，得到的eTALED6Rs诱导了有效的靶上编辑，减少了DNA和RNA水平上的旁观者编辑和脱靶编辑。最后，课题组研究人员将eTALED6和eTALED6R作为主题，在mtDNA中安装致病突变。揭示TALEDs介导的A-to-G编辑机制表明，增强BER可提高编辑效率。

据介绍，转录激活因子样效应连锁脱氨酶（TALEDs）介导其单链DNA （ssDNA）特异性腺苷脱氨酶TadA8e介导线粒体DNA （mtDNA）中的A-to-G编辑。这一过程的工作机制尚不清楚，阻碍了更有效的TALEDs的发展。

附：英文原文

Title: Leveraging base excision repair for efficient adenine base editing of mitochondrial DNA

Author: Fan, Yuhang, Xu, Wenchao, Gao, Bao-Qing, Qin, Huichao, Wu, Xiaoyi, Wei, Jia, Ni, Qingyang, Zhou, Lina, Xiang, Jiangchao, Wu, Jing, Yang, Bei, Yang, Li, Chen, Jia

Issue&Volume: 2025-03-25

Abstract: Transcription activator-like effector-linked deaminases (TALEDs) use their single-stranded DNA (ssDNA)-specific adenosine deaminase TadA8e to mediate A-to-G editing in mitochondrial DNA (mtDNA). The working mechanism of this process is unknown, hindering the development of more effective TALEDs. Here we reveal that TALED-mediated A-to-G editing relies on the formation of an ssDNA region through base excision repair (BER), which is triggered by double-stranded DNA-specific cytidine deaminase (DddA)-induced C-to-U deamination. We develop a series of enhanced TALEDs (eTALED6s) with increased editing efficiency by replacing DddA with the high-activity variant DddA6 and fusing human uracil DNA glycosylase to TadA8e. By further engineering TadA8e, the resulting eTALED6Rs induces efficient on-target editing with reduced bystander editing and off-target editing at the DNA and RNA levels. Lastly, we use eTALED6 and eTALED6R to install a pathogenic mutation in mtDNA. Revealing the mechanism of TALED-mediated A-to-G editing demonstrates that enhancing BER increases editing efficiency.

DOI: 10.1038/s41587-025-02608-w

Source: https://www.nature.com/articles/s41587-025-02608-w