Cell cycle progression in the presence of irreparable DNA damage is controlled by a Mec1-and Rad53-dependent checkpoint in budding yeast
Cell cycle progression in the presence of irreparable DNA damage is controlled by a Mec1-and Rad53-dependent checkpoint in budding yeast
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DOI：
10.1093/emboj/18.16.4485
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发表时间：
1999-08-16
期刊：
影响因子：
11.4
通讯作者：
Longhese, MP
中科院分区：
文献类型：
--
作者：
Neecke, H;Lucchini, G;Longhese, MP
我们研究了核苷酸切除修复（NER）缺陷的rad14 δ细胞在G1期对紫外线照射的反应，然后释放到细胞周期中。只有一小部分检查点蛋白似乎介导细胞周期阻滞，并在紫外线诱导的未修复病变中调节复制起源的及时激活。事实上，在G1期紫外线损伤后的rad14 Delta细胞中，需要Mec1和Rad53而不是Rad9和Rad24组检查点蛋白来延缓细胞周期进程。与此一致的是，紫外线照射后，rad14 δ细胞中也发生了依赖于mec1的Rad53磷酸化，而这与Rad9、Rad17、Rad24、Mec3和Ddc1的缺失有关，并与进入S期有关。二维凝胶分析表明，在G1期紫外线照射的rad14 Delta细胞中，晚期复制起始点并没有被激发并释放到细胞周期中，而是从早期起始点开始DNA复制，并积累复制和重组中间体。紫外线处理的ner缺陷mec1和rad53突变体在S期的进展与晚起源激活相关，这表明在不可修复的紫外线诱导的病变中，不受调节的DNA复制可能是由于未能阻止晚起源启动而导致的。
We studied the response of nucleotide excision repair (NER)-defective rad14 Delta cells to UV irradiation in G1 followed by release into the cell cycle. Only a subset of checkpoint proteins appears to mediate cell cycle arrest and regulate the timely activation of replication origins in the presence of unrepaired UV-induced lesions. In fact, Mec1 and Rad53, but not Rad9 and the Rad24 group of checkpoint proteins, are required to delay cell cycle progression in rad14 Delta cells after UV damage in G1. Consistently, Mec1-dependent Rad53 phosphorylation after UV irradiation takes place in rad14 Delta cells also in the absence of Rad9, Rad17, Rad24, Mec3 and Ddc1, and correlates with entry into S phase. Two-dimensional gel analysis indicates that late replication origins are not fired in rad14 Delta cells UV-irradiated in G1 and released into the cell cycle, which instead initiate DNA replication from early origins and accumulate replication and recombination intermediates. Progression through S phase of UV-treated NER-deficient mec1 and rad53 mutants correlates with late origin firing, suggesting that unregulated DNA replication in the presence of irreparable UV-induced lesions might result from a failure to prevent initiation at late origins.