Dcr1 senses R-loops for RNAPII termination at sites of replication stress and repair pathway choice.
Stalled RNA polymerase II (RNAPII) threatens genome integrity, yet how cells resolve transcription blocks at difficult-to-terminate sites is unclear. Leveraging the compact genome of fission yeast and termination defects associated with the non-canonical function of Dcr1, we unravel the recognition and release mechanisms of stalled RNAPII. Through dual recognition, Dcr1 senses the difficult-to-terminate context-stalled RNAPII and accumulated R-loops-and recruits the termination factor Dhp1 to ensure efficient RNAPII release. Failure of this mechanism causes termination defects that impede replication forks, necessitating DNA polymerase delta (DNAPδ)-mediated replication fork restart at stalled sites. Moreover, Dcr1 promotes genome stability by repurposing its hybrid-recognition ability to engage Rad51, thereby biasing DNA repair toward high-fidelity homologous recombination. Our work defines a key chromatin context and mechanisms governing RNAPII termination, establishing Dcr1 as a molecular hub that directly couples the fidelity of transcription termination to the stability of the genome during replication and repair.
Wang Z, Zhang Y, Guo T, He M, Xu Y, Bhattacharjee S, Martienssen RA, Ren J