Replication forks stalled at co-transcriptional R-loops can be restarted by a mechanism involving fork cleavage-religation cycles mediated by MUS81 endonuclease and DNA ligase IV (LIG4), which presumably relieve the topological barrier generated by the transcription-replication conflict (TRC) and facilitate ELL-dependent reactivation of transcription. Here, we report that the restart of R-loop-stalled replication forks via the MUS81-LIG4-ELL pathway requires senataxin (SETX), a helicase that can unwind RNA:DNA hybrids. We found that SETX promotes replication fork progression by preventing R-loop accumulation during S-phase. Interestingly, loss of SETX helicase activity leads to nascent DNA degradation upon induction of R-loop-mediated fork stalling by hydroxyurea. This fork degradation phenotype is independent of replication fork reversal and results from DNA2-mediated resection of MUS81-cleaved replication forks that accumulate due to defective replication restart. Finally, we demonstrate that SETX acts in a common pathway with the DEAD-box helicase DDX17 to suppress R-loop-mediated replication stress in human cells. A possible cooperation between these RNA/DNA helicases in R-loop unwinding at TRC sites is discussed.

• MeSH
• Flap Endonucleases metabolism   genetics   MeSH
• DEAD-box RNA Helicases * metabolism   genetics   MeSH
• DNA-Binding Proteins * metabolism   genetics   MeSH
• DNA Helicases * metabolism   genetics   MeSH
• DNA Ligase ATP metabolism   genetics   MeSH
• DNA metabolism   genetics   MeSH
• Endonucleases * metabolism   genetics   MeSH
• Transcription, Genetic MeSH
• Humans MeSH
• Multifunctional Enzymes * metabolism   genetics   MeSH
• R-Loop Structures * MeSH
• DNA Replication * MeSH
• RNA Helicases * metabolism   genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Flap Endonucleases MeSH
• DEAD-box RNA Helicases * MeSH
• DNA-Binding Proteins * MeSH
• DNA Helicases * MeSH
• DNA Ligase ATP MeSH
• DNA MeSH
• Endonucleases * MeSH
• Multifunctional Enzymes * MeSH
• MUS81 protein, human MeSH Browser
• RNA Helicases * MeSH
• SETX protein, human MeSH Browser