Transient RNA-DNA Hybrids Are Required for Efficient Double-Strand Break Repair
Transient RNA-DNA Hybrids Are Required for Efficient Double-Strand Break Repair
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DOI：
10.1016/j.cell.2016.10.001
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发表时间：
2016-11-03
期刊：
影响因子：
64.5
通讯作者：
Fischer, Tamas
中科院分区：
文献类型：
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作者：
Ohle, Corina;Tesorero, Rafael;Fischer, Tamas
RNA-DNA杂合体是细胞内DNA损伤的主要内因，它们被RNase H酶降解对于维持基因组稳定性很重要。在这里，我们确定了RNA-DNA杂交体和RNase H酶在DNA修复中的意想不到的作用。利用裂殖酵母中的位点特异性DNA双链断裂（DSB）系统，我们表明，RNA-DNA杂交形成同源重组（HR）介导的DSB修复过程的一部分，RNase H酶是必不可少的降解和有效完成的DNA修复。删除RNase H稳定了DSB位点周围的RNA-DNA杂交体，并强烈削弱了ssDNA结合RPA复合物的募集。相反，过度表达RNase H1会使这些杂交体不稳定，导致过度的链切除和RPA募集，并导致DSB周围重复区域的严重丢失。我们的研究挑战了现有的HR介导的DSB修复模型，并揭示了RNA-DNA杂交在维持基因组稳定性方面的惊人作用。
RNA-DNA hybrids are a major internal cause of DNA damage within cells, and their degradation by RNase H enzymes is important for maintaining genomic stability. Here, we identified an unexpected role for RNA-DNA hybrids and RNase H enzymes in DNA repair. Using a site-specific DNA double-strand break (DSB) system in Schizosaccharomyces pombe, we showed that RNA-DNA hybrids form as part of the homologous-recombination (HR)-mediated DSB repair process and that RNase H enzymes are essential for their degradation and efficient completion of DNA repair. Deleting RNase H stabilizes RNA-DNA hybrids around DSB sites and strongly impairs recruitment of the ssDNA-binding RPA complex. In contrast, overexpressing RNase H1 destabilizes these hybrids, leading to excessive strand resection and RPA recruitment and to severe loss of repeat regions around DSBs. Our study challenges the existing model of HR-mediated DSB repair and reveals a surprising role for RNA-DNA hybrids in maintaining genomic stability.