Persistent initiation of DNA replication and chromatin-bound MCM proteins during the cell cycle in cdc6 mutants
Persistent initiation of DNA replication and chromatin-bound MCM proteins during the cell cycle in cdc6 mutants
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DOI：
10.1101/gad.11.24.3375
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发表时间：
1997-12-15
影响因子：
10.5
通讯作者：
Stillman, B
中科院分区：
文献类型：
--
作者：
Liang, C;Stillman, B
遗传信息的忠实继承要求DNA在每个细胞周期只复制一次。DNA复制的起始涉及复制前复合物（pre-RC）的建立和随后由CDK/细胞周期蛋白激活，将pre-RC转化为post-RC。起源识别复合物（ORC），Cdc 6p，和MCM蛋白是建立前RC所必需的。我们发现，所有六个ORC亚基保持结合到染色质在整个细胞周期，而MCM蛋白周期开和关，精确地对应于RC的转换。一个新分离的cdc 6突变显示混杂启动DNA复制，增加核DNA含量，并在整个细胞周期中与染色质恒定MCM蛋白协会。这种功能获得性cdc 6突变体忽略了通常由CDK/细胞周期蛋白启动的阴性对照，表明Cdc 6p是DNA复制每细胞周期一次控制的关键介质。
Faithful inheritance of genetic information requires that DNA be copied only once each cell cycle. Initiation of DNA replication involves the establishment of a prereplication complex (pre-RC) and subsequent activation by CDK/cyclins, converting the pre-RC to a post-RC. The origin recognition complex (ORC), Cdc6p, and the MCM proteins are required for establishing the pre-RC. We show that all six ORC subunits remain bound to chromatin throughout the cell cycle, whereas the MCM proteins cycle on and off, corresponding precisely to transitions of the RC. A newly isolated cdc6 mutant displays promiscuous initiation of DNA replication, increased nuclear DNA content, and constant MCM protein association with chromatin throughout the cell cycle. This gain-of-function cdc6 mutant ignores the negative controls imposed normally on initiation by the CDK/cyclins, suggesting that Cdc6p is a key mediator of once-per-cell-cycle control of DNA replication.