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通过ORC酸化对复制原产地许可的监管揭示了Mcm2-7环闭的两步机制

Audra L Amasino^1,2, Shalini Gupta^1,2, Larry J Friedman³

¹HHMI, Massachusetts Institute of Technology, Cambridge, MA 02139.

Proceedings of the National Academy of Sciences of the United States of America

|July 10, 2023

概括

酵母中的原始识别复合体 (ORC) 的循环素依赖激酶 (CDK) 酸化阻止了DNA复制许可. 这种酸化会影响多个螺旋酶加载步骤,确保每细胞周期只发生一次复制.

科学领域:

细胞生物学细胞生物学
分子生物学分子生物学
生物化学生物化学

背景情况:

在真核细胞中,DNA复制必须在每个细胞周期中发生一次,以保持聚合性.
复制是通过分离酶负载 (G1) 和激活 (S阶段) 来调节的.
循环素依赖激酶 (CDK) 对Cdc6,Mcm2-7基酶和原产地识别复合体 (ORC) 的酸化阻止了G1.1之外的负载.

研究的目的:

为了研究CDK化ORC如何抑制原产地许可期间的Mcm2-7酶负载.
阐明Orc2和Orc6酸化在这个过程中的特定作用.

主要方法:

单分子测试用于监测原产地许可期间发生的多个事件.
实时监测评估了Mcm2-7环闭的稳定性.
评估了MO复合物的形成,这是一种需要闭环Mcm2-7的中间体.

主要成果:

化ORC招募了第一个Mcm2-7,但阻止了第二次招募.
化Orc6,而不是Orc2,促进了Mcm2-7和Cdt1.1.的快速释放.
化ORC抑制MO复合物的形成,这是稳定的Mcm2-7环闭关的关键步骤.

结论:

ORC的CDK酸化对多重螺旋酶加载步骤产生影响.
麦克米2-7环的稳定闭合是一个两步过程,涉及Cdt1释放和MO复合体形成.
这种机制确保了精确的,每细胞循环一次的DNA复制.

关键词:

复制DNA复制DNA复制DNA复制麦克米2-7是什么意思螺旋酸的使用方法启动启动启动原产地识别复合体 (ORC) 是一个复合体.

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