Human Mus81 and FANCB independently contribute to repair of DNA damage during replication
Human Mus81 and FANCB independently contribute to repair of DNA damage during replication
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DOI：
10.1111/j.1365-2443.2007.01124.x
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发表时间：
2007-10-01
期刊：
影响因子：
2.1
通讯作者：
Koyama, Hideki
中科院分区：
文献类型：
--
作者：
Nomura, Yuji;Adachi, Noritaka;Koyama, Hideki
最近的研究表明，同源重组（HR）在修复复制相关的DNA损伤中起着至关重要的作用。在哺乳动物中，Mus 81核酸内切酶和范可尼贫血（FA）通路与HR修复有关;然而，它们的功能关系尚未探索。在这里，我们敲除人类Nalm-6细胞系中的Mus 81和FANCB（FA核心复合物的一种成分）的基因。我们发现，Mus 81在细胞增殖中起着重要的作用，抑制细胞死亡时，FANCB是失踪，表明Mus 81和FA通路之间的功能联系。在DNA交联修复中，Mus 81和FA途径的作用似乎具有重叠的功能。有趣的是，Mus 81和FANCB在暴露于喜树碱（CPT）的存活中独立起作用。虽然CPT诱导的FANCD 2和Mus 81病灶与Rad 51共定位，但Mus 81的丢失，而不是FANCB，导致自发和CPT诱导的姐妹染色单体交换（SCE）水平显著降低。此外，与FANCB不同，Mus 81在基因靶向以及修复羟基脲（HU）诱导的复制叉停滞中没有显著作用。总的来说，我们的研究结果提供了第一个证据的差异功能的Mus 81和FA途径在修复DNA损伤在人类细胞复制过程中。
Recent studies suggest a crucial role for homologous recombination (HR) in repairing replication-associated DNA lesions. In mammals, the Mus81 endonuclease and the Fanconi anemia (FA) pathway have been implicated in HR repair; however, their functional relationship has remained unexplored. Here, we knockout the genes for Mus81 and FANCB, a component of the FA core complex, in the human Nalm-6 cell line. We show that Mus81 plays an important role in cell proliferation to suppress cell death when FANCB is missing, indicating a functional linkage between Mus81 and the FA pathway. In DNA cross-link repair, roles for Mus81 and the FA pathway appear to have an overlapping function. Intriguingly, Mus81 and FANCB act independently in surviving exposure to camptothecin (CPT). Although CPT-induced FANCD2 and Mus81 foci co-localize with Rad51, loss of Mus81, but not FANCB, results in significantly decreased levels of spontaneous and CPT-induced sister chromatid exchanges (SCEs). In addition, Mus81, unlike FANCB, has no significant role in gene targeting as well as in repairing hydroxyurea (HU)-induced stalls of replication forks. Collectively, our results provide the first evidence for differential functions of Mus81 and the FA pathway in repair of DNA damage during replication in human cells.