转录接近停止的DNA复制叉触发了核糖体DNA复制数的变化
Mariko Sasaki1,2,3, Takehiko Kobayashi3,4,5
1Laboratory of Gene Quantity Biology, Center for Frontier Research, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka411-8540, Japan.
Nucleic acids research
|January 29, 2025
概括
组织素脱乙酶Sir2通过防止DNA双链断裂 (DSB) 末端切除来维持核糖体DNA (rDNR) 拷贝数. 丢失Sir2导致转录复制碰撞,诱导DSB和rDNA不稳定.
科学领域:
- 细胞生物学 细胞生物学
- 分子遗传学 分子遗传学
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
背景情况:
- 基因组复制数的变化导致了基因组的不稳定.
- 核糖体DNA (rDNA) 倾向于通过重新排列或异染色体DNA形成来复制数量变化.
- 基因组脱乙酶在维持基因组稳定性方面发挥作用.
研究的目的:
- 调查素脱乙酶Sir2在维持核糖体DNA (rDNA) 复制数稳定性方面的作用.
- 阐明Sir2在DNA双链断裂 (DSB) 修复过程中防止rDNA复制数变化的机制.
主要方法:
- 作为一个模型系统,利用了芽酵母.
- 研究了DNA双链断裂 (DSB) 的形成和修复途径.
- 评估了Sir2对转录复制碰撞和同源重组 (HR) 的影响.
主要成果:
- Sir2抑制了rDNA中DNA双链断裂 (DSB) 的末端切除.
- 丢失Sir2导致在停止的复制分叉中发生转录-复制碰撞.
- 这些碰撞诱导了DSB的形成和Mre11-Rad50-Xrs2的复合体依赖性修复,促进了rDNA复制数的变化和染色体外rDNA圈.
结论:
- 通过Sir2抑制在停止的复制分叉附近的转录对于rDNA稳定性至关重要.
- Sir2将DSB修复引导到同类重组 (HR) 独立的,无重排的途径中.
- 保持rDNA复制数依赖于Sir2介导的转录复制冲突的抑制.
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