Sequential ATP hydrolysis by Cdc6 and ORC directs loading of the Mcm2-7 helicase
Sequential ATP hydrolysis by Cdc6 and ORC directs loading of the Mcm2-7 helicase
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DOI：
10.1016/j.molcel.2005.11.023
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发表时间：
2006-01-06
期刊：
影响因子：
16
通讯作者：
Bell, SP
中科院分区：
文献类型：
--
作者：
Randell, JCW;Bowers, JL;Bell, SP
Mcm 2 -7 DNA复制解旋酶在起始端附近的DNA上的装载是真核生物DNA复制起始过程中的一个关键和严格调控的事件。由此产生的蛋白质-DNA组装被称为前复制复合物（pre-RC），其形成需要起始识别复合物（ORC），Cdc 6，Cdt 1和ATP。多轮Mcm 2 - 7加载需要ORC水解ATP。在这里，我们调查的作用，ATP水解Cdc 6在前RC组装。我们发现，Cdc 6是一个ORC和起源DNA依赖的ATP酶，其功能在一个步骤之前的ATP水解ORC。抑制Cdc 6 ATP水解可稳定Cdt 1在原始DNA上的作用，并防止Mcm 2 -7负载。相比之下，Mcm 2 -7与其他RC前组分的初始结合不需要Cdc 6的ATP水解。重要的是，ORC和Cdc 6的这些协调但不同的功能确保了前RC形成的正确时间和空间调节。
Loading of the Mcm2-7 DNA replicative helicase onto origin-proximal DNA is a critical and tightly regulated event during the initiation of eukaryotic DNA replication. The resulting protein-DNA assembly is called the prereplicative complex (pre-RC), and its formation requires the origin recognition complex (ORC), Cdc6, Cdt1, and ATP. ATP hydrolysis by ORC is required for multiple rounds of Mcm2-7loading. Here, we investigate the role of ATP hydrolysis by Cdc6 during pre-RC assembly. We find that Cdc6 is an ORC- and origin DNA-dependent ATPase that functions at a step preceding ATP hydrolysis by ORC. Inhibiting Cdc6 ATP hydrolysis stabilizes Cdt1 on origin DNA and prevents Mcm2-7 loading. In contrast, the initial association of Mcm2-7 with the other pre-RC components does not require ATP hydrolysis by Cdc6. Importantly, these coordinated yet distinct functions of ORC and Cdc6 ensure the correct temporal and spatial regulation of pre-RC formation.