The Smc5/6 complex regulates the yeast Mph1 helicase at RNA-DNA hybrid-mediated DNA damage

PLoS Genet. 2017 Dec 27;13(12):e1007136. doi: 10.1371/journal.pgen.1007136. eCollection 2017 Dec.


RNA-DNA hybrids are naturally occurring obstacles that must be overcome by the DNA replication machinery. In the absence of RNase H enzymes, RNA-DNA hybrids accumulate, resulting in replication stress, DNA damage and compromised genomic integrity. We demonstrate that Mph1, the yeast homolog of Fanconi anemia protein M (FANCM), is required for cell viability in the absence of RNase H enzymes. The integrity of the Mph1 helicase domain is crucial to prevent the accumulation of RNA-DNA hybrids and RNA-DNA hybrid-dependent DNA damage, as determined by Rad52 foci. Mph1 forms foci when RNA-DNA hybrids accumulate, e.g. in RNase H or THO-complex mutants and at short telomeres. Mph1, however is a double-edged sword, whose action at hybrids must be regulated by the Smc5/6 complex. This is underlined by the observation that simultaneous inactivation of RNase H2 and Smc5/6 results in Mph1-dependent synthetic lethality, which is likely due to an accumulation of toxic recombination intermediates. The data presented here support a model, where Mph1's helicase activity plays a crucial role in responding to persistent RNA-DNA hybrids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • DEAD-box RNA Helicases / genetics*
  • DEAD-box RNA Helicases / metabolism*
  • DNA / metabolism
  • DNA Damage*
  • DNA Repair
  • DNA Replication / genetics
  • DNA Replication / physiology
  • RNA Helicases / metabolism
  • RNA, Fungal / genetics*
  • RNA, Fungal / metabolism
  • Ribonuclease H / genetics
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism*


  • Cell Cycle Proteins
  • RNA, Fungal
  • SMC5 protein, S cerevisiae
  • SMC6 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • DNA
  • Ribonuclease H
  • MPH1 protein, S cerevisiae
  • DEAD-box RNA Helicases
  • RNA Helicases

Grant support

This work was supported by grants from the Spanish Ministry of Economy and Competitiveness (BFU2013-42918-P & BFU2016-75058-P),; Junta de Andalucía (BIO1238),; the European Research Council (ERC2014 AdG669898 TARLOOP),; the Danish Council for Independent Research,; the Villum Foundation,; European Research Council (ERCStG, no. 242905); BMBF-GerontoSys II network AGENET (FKZ0315898),; CancerTelSys (01ZX1302) in the E:med program of the German Federal Ministry of Education and Research (BMBF),; Instituto Carlos III (Spanish Ministry of Health) to JLB; Scientific Foundation of the Spanish Association Against Cancer to BGG; Fundação para a Ciência e a Tecnologia to SS; EMBO/Marie Curie co-fund fellowship to SLG (ALTF 9-2010),; European Union (FEDER). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.