A CSB-PAF1 axis activates RNA polymerase II from promoter-proximal sites and restores efficient transcription elongation after DNA damage repair

ABSTRACT: The coordinated transcription of genes involves RNA polymerase II enzymes (RNAPII), which pull DNA through their active sites. DNA lesions in transcribed strands block RNAPII elongation and induce a strong transcriptional arrest. The transcription-coupled repair (TCR) pathway ensures the efficient removal of transcription-blocking DNA lesions, but this is not sufficient to overcome this arrest and resume transcription. Through proteomics screens, we find that the TCR-specific CSB protein loads the evolutionary conserved PAF1 complex (PAF1C) onto RNAPII in promoter-proximal regions specifically in response to DNA damage. PAF1C is dispensable for TCR-mediated repair,but is essential to resume RNA synthesis after UV irradiation, suggesting an unexpected uncoupling between DNA repair and transcription restart. Moreover, we find that PAF1C promotes RNAPII pause release in promoter-proximal regions and subsequently acts as a processivity factor that stimulates transcription elongation waves throughout genes. Our findings expose the molecular basis for a non-canonical PAF1C-dependent pathway that restores transcription throughout the human genome after genotoxic stress.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Román González-Prieto  

LAB HEAD: Alfred CO Vertegaal

PROVIDER: PXD016198 | Pride | 2021-02-28

REPOSITORIES: Pride