Transcription-coupled DNA–protein crosslink repair by CSB and CRL4CSA-mediated degradation
Marjolein van Sluis, Qing Yu, Melanie van der Woude, Camila Gonzalo-Hansen, Shannon Dealy, Roel C. Janssens, Hedda B. Somsen, Anisha R. Ramadhin, Dick H. W. Dekkers, Hannah Lena Wienecke, Joris Demmers, Anja Raams, Carlota Davó-Martínez, Diana A. Llerena Schiffmacher, Marvin van Toorn, David Häckes, Karen L. Thijssen, Di Zhou, J.G. Lammers, Alex Pines, Wim Vermeulen, Joris Pothof, Jeroen Demmers, Debbie L. C. van den Berg, Hannes Lans, Jurgen A. Marteijn
Abstract
Abstract 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 CSA and the proteasome. Thus, DPCs in genes are preferentially repaired in a transcription-coupled manner to facilitate unperturbed transcription.