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

Chang, E. Y.-C.; Wells, J. P.; Tsai, S.-H.; Coulombe, Y.; Chan, Y. A.; Zhu, Y. D.; Fournier, L.-A.; Hieter, P.; Masson, J.-Y.; Stirling, P. C.

doi:10.1101/472654

bioRxiv · 10.1101/472654

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

Chang, E. Y.-C.·Wells, J. P.·Tsai, S.-H.·Coulombe, Y.·Chan, Y. A.·Zhu, Y. D.·Fournier, L.-A.·Hieter, P.·Masson, J.-Y.·Stirling, P. C.

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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 such as RAD50. We show in yeast and human cells that R-loops accumulate during RAD50 depletion. In human cancer cell models, we find that RAD50 and its partners in the MRE11-RAD50-NBS1 complex regulate R-loop-associated DNA damage and replication stress. We show that a non-nucleolytic function of MRE11 is important for R-loop suppression via activation of PCNA-ubiquitination by RAD18 and recruiting anti-R-loop helicases in the Fanconi Anemia pathway. This work establishes a novel role for MRE11-RAD50-NBS1 in directing tolerance mechanisms of transcription-replication conflicts.

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Chang, E. Y.-C., Wells, J. P., Tsai, S.-H., Coulombe, Y., Chan, Y. A., Zhu, Y. D., Fournier, L.-A., Hieter, P., Masson, J.-Y., Stirling, P. C.. 2018-11-17. MRE11-RAD50-NBS1 activates Fanconi Anemia R-loop suppression at transcription-replication conflicts. https://doi.org/10.1101/472654

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