Reconstitution of an ATM-dependent checkpoint that inhibits chromosomal DNA replication following DNA damage
Reconstitution of an ATM-dependent checkpoint that inhibits chromosomal DNA replication following DNA damage
复制标题
DOI：
10.1016/s1097-2765(00)00063-0
复制
发表时间：
2000-09-01
期刊：
影响因子：
16
通讯作者：
Gautier, J
中科院分区：
文献类型：
--
作者：
Costanzo, V;Robertson, K;Gautier, J
细胞周期检查点在DNA损伤后会抑制细胞周期进程。从非洲爪蟾卵中建立了一种无细胞体系，该体系重建了抑制DNA复制起始的检查点通路。含有双链断裂的DNA以剂量依赖的方式抑制复制起始。在检查点激活时，会组装一个前复制复合物，其中包含起始识别复合物（ORC）、细胞分裂周期蛋白6（Cdc6）、细胞分裂周期蛋白7（Cdc7）和微小染色体维持蛋白（MCM），但缺少细胞分裂周期蛋白45（Cdc45）。该检查点依赖于共济失调毛细血管扩张突变蛋白（ATM）。细胞周期蛋白依赖性激酶2（Cdk2）/细胞周期蛋白E（CyclinE）在ATM的下游发挥作用，并且通过酪氨酸15位点的Cdk2磷酸化而下调。Cdk2AF/CyclinE对检查点信号不敏感，细胞分裂周期蛋白25A（Cdc25A）可越过检查点并恢复DNA复制。本报告描述了一种DNA损伤检查点通路，该通路在脊椎动物中独立于p53的转录功能阻止S期的开始。
Cell cycle checkpoints lead to the inhibition of cell cycle progression following DNA damage. A cell-free system derived from Xenopus eggs has been established that reconstitutes the checkpoint pathway inhibiting DNA replication initiation. DNA containing double-strand breaks inhibits replication initiation in a dose-dependent manner. Upon checkpoint activation, a prereplicative complex is assembled that contains ORC, Cdc6, Cdc7, and MCM proteins but lacks Cdc45. The checkpoint is ATM dependent. Cdk2/CyclinE acts downstream of ATM and is downregulated by Cdk2 phosphorylation on tyrosine 15. Cdk2AF/CyclinE is refractory to checkpoint signaling, and Cdc25A overrides the checkpoint and restores DNA replication. This report provides the description of a DNA damage checkpoint pathway that prevents the onset of S phase independently of the transcriptional function of p53 in a vertebrate organism.