RECQ5 Helicase Cooperates with MUS81 Endonuclease in Processing Stalled Replication Forks at Common Fragile Sites during Mitosis

  • Mol Cell. 2017 Jun 1;66(5):658-671.e8. doi: 10.1016/j.molcel.2017.05.006.
Stefano Di Marco  1 ,  Zdenka Hasanova  2 ,  Radhakrishnan Kanagaraj  1 ,  Nagaraja Chappidi  1 ,  Veronika Altmannova  3 ,  Shruti Menon  1 ,  Hana Sedlackova  2 ,  Jana Langhoff  1 ,  Kalpana Surendranath  4 ,  Daniela Hühn  1 ,  Rahul Bhowmick  5 ,  Victoria Marini  2 ,  Stefano Ferrari  1 ,  Ian D Hickson  5 ,  Lumir Krejci  6 ,  Pavel Janscak  7
Affiliations
  • 1. Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
  • 2. Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5/A7, Brno 62500, Czech Republic.
  • 3. Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5/A7, Brno 62500, Czech Republic; International Clinical Research Center, St. Anne's University Hospital, Pekarska 53, Brno 656 91, Czech Republic.
  • 4. Department of Biomedical Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
  • 5. Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Insitute Building 18.1, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
  • 6. Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5/A7, Brno 62500, Czech Republic; International Clinical Research Center, St. Anne's University Hospital, Pekarska 53, Brno 656 91, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5/A4, 625 00, Brno, Czech Republic. Electronic address: [email protected].
  • 7. Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland. Electronic address: [email protected].
PMID: 28575661 DOI: 10.1016/j.molcel.2017.05.006
Abstract

The MUS81-EME1 Endonuclease cleaves late replication intermediates at common fragile sites (CFSs) during early Mitosis to trigger DNA-repair synthesis that ensures faithful chromosome segregation. Here, we show that these DNA transactions are promoted by RECQ5 DNA helicase in a manner dependent on its Ser727 phosphorylation by CDK1. Upon replication stress, RECQ5 associates with CFSs in early Mitosis through its physical interaction with MUS81 and promotes MUS81-dependent mitotic DNA synthesis. RECQ5 depletion or mutational inactivation of its ATP-binding site, RAD51-interacting domain, or phosphorylation site causes excessive binding of RAD51 to CFS loci and impairs CFS expression. This leads to defective chromosome segregation and accumulation of CFS-associated DNA damage in G1 cells. Biochemically, RECQ5 alleviates the inhibitory effect of RAD51 on 3'-flap DNA cleavage by MUS81-EME1 through its RAD51 filament disruption activity. These data suggest that RECQ5 removes RAD51 filaments stabilizing stalled replication forks at CFSs and hence facilitates CFS cleavage by MUS81-EME1.

Keywords
MUS81; RAD51 filament; RECQ5; common fragile sites; genomic instability; mitotic DNA synthesis; replication stress.