波尔α-原酶是如何向复制体的,以促进真核细胞DNA复制的
Morgan L Jones1, Valentina Aria1, Yasemin Baris1
1MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
Molecular cell
|July 28, 2023
概括
DNA复制依赖于Pol α-原酶来创建原始体. 新的冷EM结构揭示了Pol α-原酶直接与CMG基酶结合,协调DNA在复制分叉中的原始化.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 生物化学 生物化学
背景情况:
- DNA复制需要多种蛋白质的精确协调.
- 聚α-原酶合成RNA-DNA原始酶,对于领先和滞后链的合成至关重要.
- 对于Polα-原酶对复制分叉的精确准机制的理解尚不完全.
研究的目的:
- 阐明在真核细胞DNA复制过程中Polα-原酶被复制体所准和协调的保存机制.
- 确定Polα-原酶与CMG酶相互作用的结构基础.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 确定了含有Polα-primase的青酵母和人类复合体的结构.
- 进行了体外DNA复制试验和酵母细胞生长研究,以评估已识别的相互作用的功能意义.
主要成果:
- 低温EM结构揭示了一种保存的机制,其中Pol α-原酶直接与CMG (CDC45-MCM-GINS) 复制性酶结合.
- 聚α-原酶的非催化PRIM2/Pri2亚单元与CMG形成了关键接口.
- 这些相互作用使催化PRIM1/Pri1子单元在滞后链模板上进行高效的原始化,克服RPA竞争.
结论:
- 已经确定了Pol α-原酶的复复体介导协调的保存机制.
- 聚甲酶 (PRIM2) 和CMG酶之间的直接相互作用对于DNA复制和细胞活力至关重要.
- 结构性发现解释了滞后链模板上的偏好原始化,并提供了克服RPA抑制的洞察力.
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