远程DNA末端切除支持通过检查点激活进行同源重组,而不是广泛的同源生成
Michael T Kimble1,2, Matthew J Johnson1,2, Mattie R Nester2
1Program in Biological Sciences, Columbia University, New York, United States.
eLife
|June 30, 2023
概括
通过Exo1和Sgs1进行长距离DNA末端切除对于酵母中遥远的DNA重复之间的同源重组至关重要,但对于附近的重复来说并不重要. 这个过程与DNA损伤检查点和染色体移动性有关.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 细胞生物学 细胞生物学
背景情况:
- 同源重组 (HR) 使用高保真机制修复DNA双链断裂 (DSB).
- HR涉及DNA末端切除,其中核酶降解5'末端.
- 长距离切除核酶 (Exo1,Sgs1-Dna2) 在HR中的特定作用尚不清楚.
研究的目的:
- 调查Exo1和Sgs1在同源重组中的特定背景作用.
- 确定长距离切除,DNA损伤检查点和染色体间重组之间的关系.
主要方法:
- 在 *Saccharomyces cerevisiae* (酵母菌) 中使用删除突变物 (*exo1∆*, *sgs1∆*) 进行遗传分析.
- 评估密切相关和遥远 (染色体间) 重复之间的重组频率.
- 研究DNA损伤检查点和染色体移动性的作用.
主要成果:
- Exo1和Sgs1对于染色体间HR是必不可少的,但对于密切相关的重复之间再组合而言却不是.
- 需要进行长距离切除才能激活DNA损伤检查点,这对染色体间HR至关重要.
- 检查点突变体在染色体间重组中表现出缺陷,检查点激活部分拯救了*exo1∆ sgs1∆*突变体.
- 仅仅是细胞周期延迟并不能挽救缺陷,这表明了额外的检查点功能.
结论:
- 长距离切除和DNA损伤检查点对于酵母的染色体间HR至关重要.
- 检查点可能通过增加染色体的移动性来促进HR,从而使遥远的同源位点能够配对.
- 在DSB和修复模板之间的近距离绕过了长距离切除的需要.
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