Transcription-coupled repair of DNA-protein crosslinks

Acampora, Aleida (2023): Transcription-coupled repair of DNA-protein crosslinks. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

Abstract

DNA is a naturally fragile molecule that is intrinsically susceptible to damage. A huge variety of endogenous and exogenous insults can challenge DNA integrity; therefore, specialized DNA repair pathways operate in cells to ensure genome stability. DNA-protein crosslinks (DPCs) are particularly toxic DNA lesions that, due to their bulky nature, can interfere with every chromatin process such as replication and transcription. In the last decade, a multitude of general and dedicated mechanisms have been identified to be involved in DPC resolution. It has been shown that when a DPC blocks replication, proteolytic degradation of the crosslinked protein is required to allow fork resumption. DPCs can also hamper RNAPII progression, however how cells respond to DPCs-dependent transcription blockage is unknown. In this study we uncovered that DPCs induced by formaldehyde (FA) shut down transcription and induce degradation of RNA polymerase II (RNAPII). DPC induction by FA treatment triggers the recruitment of the upstream transcription-coupled NER (TC-NER) factors CSB and CSA to stalled RNAPII. Accordingly, CSB and CSA provide resistance towards DPCs-inducing agents and their loss impairs efficient transcription recovery after FA treatment. Conversely, TC-NER factors acting downstream of CSB and CSA are not required for transcription resumption upon FA treatment. In addition, genetic data suggest that CSB promotes DPC tolerance in parallel to and independently of already known DPC repair factors. Lastly, using our newly established DPC-sequencing (DPC-seq) assay for the genome-wide mapping of DPCs, we discovered that CSB specifically promotes DPC repair in actively transcribed genes. Therefore, this study provides the first evidence for the existence of a CSB-dependent specialized transcription-coupled DPC repair pathway.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 540 Chemie
• Fakultäten: Fakultät für Chemie und Pharmazie
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 13. Dezember 2023
• 1. Bericht­erstatter:in: Stingele, Julian