RESUMEN
Congenital nucleotide excision repair (NER) deficiency gives rise to several cancer-prone and/or progeroid disorders. It is not understood how defects in the same DNA repair pathway cause different disease features and severity. Here, we show that the absence of functional ERCC1-XPF or XPG endonucleases leads to stable and prolonged binding of the transcription/DNA repair factor TFIIH to DNA damage, which correlates with disease severity and induces senescence features in human cells. In vivo, in C. elegans, this prolonged TFIIH binding to non-excised DNA damage causes developmental arrest and neuronal dysfunction, in a manner dependent on transcription-coupled NER. NER factors XPA and TTDA both promote stable TFIIH DNA binding and their depletion therefore suppresses these severe phenotypical consequences. These results identify stalled NER intermediates as pathogenic to cell functionality and organismal development, which can in part explain why mutations in XPF or XPG cause different disease features than mutations in XPA or TTDA.
Asunto(s)
Caenorhabditis elegans , Daño del ADN , Reparación del ADN , Proteínas de Unión al ADN , Endonucleasas , Factor de Transcripción TFIIH , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Humanos , Animales , Factor de Transcripción TFIIH/metabolismo , Factor de Transcripción TFIIH/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Endonucleasas/metabolismo , Endonucleasas/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteína de la Xerodermia Pigmentosa del Grupo A/metabolismo , Proteína de la Xerodermia Pigmentosa del Grupo A/genética , Unión Proteica , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Mutación , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genéticaRESUMEN
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 CRL4CSA and the proteasome. Thus, DPCs in genes are preferentially repaired in a transcription-coupled manner to facilitate unperturbed transcription.
