MRE11-RAD50-NBS1 promotes Fanconi Anemia R-loop suppression at transcription-replication conflicts

Nat Commun. 2019 Sep 19;10(1):4265. doi: 10.1038/s41467-019-12271-w.

Abstract

Ectopic R-loop accumulation causes DNA replication stress and genome instability. To avoid these outcomes, cells possess a range of anti-R-loop mechanisms, including RNaseH that degrades the RNA moiety in R-loops. To comprehensively identify anti-R-loop mechanisms, we performed a genome-wide trigenic interaction screen in yeast lacking RNH1 and RNH201. We identified >100 genes critical for fitness in the absence of RNaseH, which were enriched for DNA replication fork maintenance factors including the MRE11-RAD50-NBS1 (MRN) complex. While MRN has been shown to promote R-loops at DNA double-strand breaks, we show that it suppresses R-loops and associated DNA damage at transcription-replication conflicts. This occurs through a non-nucleolytic function of MRE11 that is important for R-loop suppression by the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms at transcription-replication conflicts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Anhydride Hydrolases / genetics
  • Acid Anhydride Hydrolases / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • DNA Damage / genetics
  • DNA Replication / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Fanconi Anemia / genetics
  • Fanconi Anemia / metabolism*
  • Genomic Instability / genetics*
  • Humans
  • MRE11 Homologue Protein / genetics
  • MRE11 Homologue Protein / metabolism*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • R-Loop Structures / genetics*
  • Ribonuclease H / genetics
  • Schizosaccharomyces / genetics
  • Transcription, Genetic / genetics

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • MRE11 protein, human
  • NBN protein, human
  • Nuclear Proteins
  • MRE11 Homologue Protein
  • Ribonuclease H
  • Acid Anhydride Hydrolases
  • RAD50 protein, human

Grants and funding