Fanconi-Anemia-Associated Mutations Destabilize RAD51 Filaments and Impair Replication Fork Protection
Fanconi-Anemia-Associated Mutations Destabilize RAD51 Filaments and Impair Replication Fork Protection
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DOI：
10.1016/j.celrep.2017.09.062
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发表时间：
2017-10-10
期刊：
影响因子：
8.8
通讯作者：
Krejci, Lumir
中科院分区：
文献类型：
--
作者：
Zadorozhny, Karina;Sannino, Vincenzo;Krejci, Lumir
范可尼贫血（Fanconi anemia， FA）是一种以DNA链间交联（ICL）修复缺陷、染色体不稳定和易患癌症为特征的遗传性疾病。最近，两个RAD51突变被报道导致fa样表型。尽管FA/HR蛋白在正常复制过程中与复制叉（RF）稳定密切相关，但FA相关的RAD51突变如何影响ICL病变以外的复制仍不清楚。在这里，我们报道这些突变不能保护新生DNA免受非洲爪蟾卵提取物RF停滞期间mre11介导的降解。DNA保护的体外重建表明，缺陷是由RAD51性质的改变直接引起的。这两种突变都会引起显著的结构变化和RAD51丝的不稳定，这种不稳定不能通过防止ATP水解来挽救。我们的研究结果进一步将FA通路与DNA复制联系起来，并为RAD51在不依赖重组的基因组维持机制中的作用提供了机制见解。
Fanconi anemia (FA) is a genetic disorder characterized by a defect in DNA interstrand crosslink (ICL) repair, chromosomal instability, and a predisposition to cancer. Recently, two RAD51 mutations were reported to cause an FA-like phenotype. Despite the tight association of FA/HR proteins with replication fork (RF) stabilization during normal replication, it remains unknown how FA-associated RAD51 mutations affect replication beyond ICL lesions. Here, we report that these mutations fail to protect nascent DNA from MRE11-mediated degradation during RF stalling in Xenopus laevis egg extracts. Reconstitution of DNA protection in vitro revealed that the defect arises directly due to altered RAD51 properties. Both mutations induce pronounced structural changes and RAD51 filament destabilization that is not rescued by prevention of ATP hydrolysis due to aberrant ATP binding. Our results further interconnect the FA pathway with DNA replication and provide mechanistic insight into the role of RAD51 in recombination-independent mechanisms of genome maintenance.