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

• Published in: Nature communications Vol. 10; no. 1; pp. 4265 - 15
• Main Authors: Chang, Emily Yun-Chia, Tsai, Shuhe, Aristizabal, Maria J., Wells, James P., Coulombe, Yan, Busatto, Franciele F., Chan, Yujia A., Kumar, Arun, Dan Zhu, Yi, Wang, Alan Ying-Hsu, Fournier, Louis-Alexandre, Hieter, Philip, Kobor, Michael S., Masson, Jean-Yves, Stirling, Peter C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.09.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 13/89; 14; 14/1; 14/63; 42; 45; 45/15; 49; 49/40; 631/208/211; 631/337/1427; 631/337/151/2356; Acid Anhydride Hydrolases - genetics; Acid Anhydride Hydrolases - metabolism; Anemia; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA damage; DNA Damage - genetics; DNA Replication - genetics; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Fanconi Anemia - genetics; Fanconi Anemia - metabolism; Fanconi syndrome; Fitness; Genomes; Genomic instability; Genomic Instability - genetics; Humanities and Social Sciences; Humans; MRE11 Homologue Protein - genetics; MRE11 Homologue Protein - metabolism; MRE11 protein; multidisciplinary; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; R-Loop Structures - genetics; R-loops; Replication; Ribonuclease H - genetics; Ribonucleic acid; RNA; Schizosaccharomyces - genetics; Science; Science (multidisciplinary); Transcription; Transcription, Genetic - genetics; Yeast; Yeasts
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-12271-w

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. Accumulations of R-loops can lead to genome instability. Here the authors reveal a role for the MRN complex in suppressing R-loops and associated DNA damage at transcription–replication conflicts.