Genome Integrity Group, Danish Cancer Society Research Center, Strandboulevarden 49, Copenhagen, DK-2100, Denmark.
Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013, Seville, Spain.
Nat Commun. 2022 Sep 9;13(1):5303. doi: 10.1038/s41467-022-33027-z.
The RNA world is changing our views about sensing and resolution of DNA damage. Here, we develop single-molecule DNA/RNA analysis approaches to visualize how nascent RNA facilitates the repair of DNA double-strand breaks (DSBs). RNA polymerase II (RNAPII) is crucial for DSB resolution in human cells. DSB-flanking, RNAPII-generated nascent RNA forms RNA:DNA hybrids, guiding the upstream DNA repair steps towards favouring the error-free Homologous Recombination (HR) pathway over Non-Homologous End Joining. Specific RNAPII inhibitor, THZ1, impairs recruitment of essential HR proteins to DSBs, implicating nascent RNA in DNA end resection, initiation and execution of HR repair. We further propose that resection factor CtIP interacts with and helps re-activate RNAPII when paused by the RNA:DNA hybrids, collectively promoting faithful repair of chromosome breaks to maintain genomic integrity.
RNA 世界正在改变我们对 DNA 损伤感应和修复的看法。在这里，我们开发了单分子 DNA/RNA 分析方法来可视化新生 RNA 如何促进 DNA 双链断裂 (DSB) 的修复。RNA 聚合酶 II (RNAPII) 对于人类细胞中 DSB 的修复至关重要。DSB 侧翼、RNAPII 产生的新生 RNA 形成 RNA:DNA 杂交体，引导上游 DNA 修复步骤，有利于无差错同源重组 (HR) 途径而不是非同源末端连接。特定的 RNAPII 抑制剂 THZ1 会损害关键 HR 蛋白向 DSB 的募集，这表明新生 RNA 参与了 DNA 末端切除、同源重组修复的起始和执行。我们进一步提出，当 RNA:DNA 杂交体使 RNAPII 暂停时，切除因子 CtIP 与 RNAPII 相互作用并帮助其重新激活，共同促进染色体断裂的忠实修复，以维持基因组完整性。
