RTEL1 helicase is a component of DNA repair and telomere maintenance machineries. While RTEL1's role in DNA replication is emerging, how RTEL1 preserves genomic stability during replication remains elusive. Here we used a range of proteomic, biochemical, cell, and molecular biology and gene editing approaches to provide further insights into potential role(s) of RTEL1 in DNA replication and genome integrity maintenance. Our results from complementary human cell culture models established that RTEL1 and the Polδ subunit Poldip3 form a complex and are/function mutually dependent in chromatin binding after replication stress. Loss of RTEL1 and Poldip3 leads to marked R-loop accumulation that is confined to sites of active replication, enhances endogenous replication stress, and fuels ensuing genomic instability. The impact of depleting RTEL1 and Poldip3 is epistatic, consistent with our proposed concept of these two proteins operating in a shared pathway involved in DNA replication control under stress conditions. Overall, our data highlight a previously unsuspected role of RTEL1 and Poldip3 in R-loop suppression at genomic regions where transcription and replication intersect, with implications for human diseases including cancer.

中文翻译：

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人类RTEL1与Poldip3相关联，以促进对复制压力和R环分辨率的反应。

RTEL1解旋酶是DNA修复和端粒维护机制的组成部分。尽管RTEL1在DNA复制中的作用正在逐渐显现，但RTEL1如何在复制过程中保持基因组稳定性仍然不清楚。在这里，我们使用了一系列蛋白质组学，生化，细胞和分子生物学以及基因编辑方法，以进一步了解RTEL1在DNA复制和基因组完整性维护中的潜在作用。我们从互补的人类细胞培养模型中得到的结果表明，复制应力后RTEL1和Polδ亚基Poldip3形成复合物，并且/功能相互依赖于染色质结合。RTEL1和Poldip3的缺失会导致显着的R环积累，其局限于活动复制位点，增加内源性复制压力，并加剧了基因组的不稳定性。耗尽RTEL1和Poldip3的影响是上位性的，这与我们提出的这两种蛋白在压力条件下以参与DNA复制控制的共享途径起作用的概念一致。总体而言，我们的数据突显了RTEL1和Poldip3在转录和复制相交的基因组区域R环抑制中的作用，此前从未料想不到，这对包括癌症在内的人类疾病具有影响。