联酶3防止氧化链断裂诱导的线粒体DNA损失,但对于复制循环化并非必不可少
Genevieve Trombly1, Afaf Milad Said1, Alexei P Kudin1
1Institute of Experimental Epileptology and Cognition Research, Medical Faculty, University of Bonn, Bonn 53127, Germany.
Nucleic acids research
|October 16, 2025
概括
DNA连接酶3 (LIG3) 对于修复由氧化应激引起的线粒体DNA (mtDNA) 断裂至关重要. 它在细胞中的失活防止mtDNA损失,突出LIG3的作用.
科学领域:
- 线粒体生物学 线粒体生物学
- DNA 修复机制的修复机制
- 遗传学和基因组学 遗传学和基因组学
背景情况:
- 线粒体DNA连接酶 (LIG3) 假设在线粒体DNA (mtDNA) 复制和修复中发挥关键作用.
- 以前的研究表明,由于严重的mtDNA损失,LIG3缺乏导致小鼠胚胎死亡.
研究的目的:
- 研究LIG3在维持人类细胞mtDNA完整性的作用.
- 阐明LIG3在修复线粒体内的氧化DNA损伤中的作用.
主要方法:
- 基因组编辑被用来使HEK 293细胞中的LIG3基因失活.
- 测定了线粒体DNA拷贝数.
- 使用超深度长读测序来分析mtDNA完整性.
- 评估了细胞对氧化应激的反应.
主要成果:
- 激活LIG3导致mtDNA复制数的适度下降,但并没有停止mtDNA合成.
- 观察到mtDNA单链和双链断裂的频率增加,特别是在富含GC的区域.
- 在氧化应激下,LIG3缺乏的细胞表现出线性mtDNA的加速降解和严重的mtDNA损失.
- mtDNA断裂的频率与氧气水平和活性氧物种 (ROS) 防御酶表达相关.
结论:
- LIG3对于防止氧化损伤导致的mtDNA损失至关重要.
- 在mtDNA中氧化单链断裂是mtDNA周转的一个重要因素.
- 在维护线粒体基因组稳定性方面,LIG3起着至关重要的作用.
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