Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands.
Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands.
Nat Cell Biol. 2024 May;26(5):770-783. doi: 10.1038/s41556-024-01394-y. Epub 2024 Apr 10.
DNA-protein crosslinks (DPCs) arise from enzymatic intermediates, metabolism or chemicals like chemotherapeutics. DPCs are highly cytotoxic as they impede DNA-based processes such as replication, which is counteracted through proteolysis-mediated DPC removal by spartan (SPRTN) or the proteasome. However, whether DPCs affect transcription and how transcription-blocking DPCs are repaired remains largely unknown. Here we show that DPCs severely impede RNA polymerase II-mediated transcription and are preferentially repaired in active genes by transcription-coupled DPC (TC-DPC) repair. TC-DPC repair is initiated by recruiting the transcription-coupled nucleotide excision repair (TC-NER) factors CSB and CSA to DPC-stalled RNA polymerase II. CSA and CSB are indispensable for TC-DPC repair; however, the downstream TC-NER factors UVSSA and XPA are not, a result indicative of a non-canonical TC-NER mechanism. TC-DPC repair functions independently of SPRTN but is mediated by the ubiquitin ligase CRL4 and the proteasome. Thus, DPCs in genes are preferentially repaired in a transcription-coupled manner to facilitate unperturbed transcription.
DNA-蛋白质交联（DPCs）是由酶中间体、代谢产物或化疗药物等引起的。DPCs 具有高度细胞毒性，因为它们会阻碍基于 DNA 的过程，如复制，而通过 Spartan（SPRTN）或蛋白酶体介导的 DPC 去除的蛋白水解来对抗这种影响。然而，DPCs 是否会影响转录以及如何修复阻止转录的 DPC 仍然知之甚少。在这里，我们表明 DPCs 严重阻碍 RNA 聚合酶 II 介导的转录，并通过转录偶联 DPC（TC-DPC）修复在活性基因中优先修复。TC-DPC 修复是通过将转录偶联核苷酸切除修复（TC-NER）因子 CSB 和 CSA 招募到 DPC 停滞的 RNA 聚合酶 II 上启动的。CSA 和 CSB 对于 TC-DPC 修复是不可或缺的；然而，下游的 TC-NER 因子 UVSSA 和 XPA 则不是，这表明存在非典型的 TC-NER 机制。TC-DPC 修复独立于 SPRTN 而发挥作用，但由泛素连接酶 CRL4 和蛋白酶体介导。因此，基因中的 DPC 以转录偶联的方式优先修复，以促进不受干扰的转录。
