Checkpoint inhibition of origin firing prevents DNA topological stress.
Checkpoint inhibition of origin firing prevents DNA topological stress.
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原点激发的检查点抑制可防止 DNA 拓扑应力。
DOI：
10.1101/gad.328682.119
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发表时间：
2019
影响因子：
10.5
通讯作者：
Morafraile EC
中科院分区：
文献类型：
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作者：
Morafraile EC
真核生物中DNA损伤和复制应激的一个普遍特征是检查点激酶反应的激活。在S期，检查点抑制复制启动，但这个全局块的功能，起源发射仍然未知。为了建立这一臂的检查点的生理作用，我们分析了分离功能突变体的芽殖酵母酿酒酵母，允许全球起源射击后复制应力，尽管在其他方面正常的检查点响应。使用遗传筛选，我们表明，缺乏检查点块起源射击的结果依赖于所需的拓扑问题的解决途径。未能抑制复制起始确实会导致DNA链化增加，导致DNA损伤和染色体丢失。我们进一步表明，这种拓扑压力不仅是一个失败的检查点响应的后果，但也发生在一个未受干扰的S-阶段时，太多的起源同时火灾。我们一起揭示了限制复制起始事件数量的作用是防止DNA拓扑问题，这可能与拓扑异构酶和检查点抑制剂治疗癌症有关。
A universal feature of DNA damage and replication stress in eukaryotes is the activation of a checkpoint-kinase response. In S-phase, the checkpoint inhibits replication initiation, yet the function of this global block to origin firing remains unknown. To establish the physiological roles of this arm of the checkpoint, we analyzed separation of function mutants in the budding yeast Saccharomyces cerevisiae that allow global origin firing upon replication stress, despite an otherwise normal checkpoint response. Using genetic screens, we show that lack of the checkpoint-block to origin firing results in a dependence on pathways required for the resolution of topological problems. Failure to inhibit replication initiation indeed causes increased DNA catenation, resulting in DNA damage and chromosome loss. We further show that such topological stress is not only a consequence of a failed checkpoint response but also occurs in an unperturbed S-phase when too many origins fire simultaneously. Together we reveal that the role of limiting the number of replication initiation events is to prevent DNA topological problems, which may be relevant for the treatment of cancer with both topoisomerase and checkpoint inhibitors.