BRCA1 promotes unloading of the CMG helicase from a stalled DNA replication fork

Mol Cell. 2014 Oct 2;56(1):174-85. doi: 10.1016/j.molcel.2014.08.012. Epub 2014 Sep 11.


The tumor suppressor protein BRCA1 promotes homologous recombination (HR), a high-fidelity mechanism to repair DNA double-strand breaks (DSBs) that arise during normal replication and in response to DNA-damaging agents. Recent genetic experiments indicate that BRCA1 also performs an HR-independent function during the repair of DNA interstrand crosslinks (ICLs). Here we show that BRCA1 is required to unload the CMG helicase complex from chromatin after replication forks collide with an ICL. Eviction of the stalled helicase allows leading strands to be extended toward the ICL, followed by endonucleolytic processing of the crosslink, lesion bypass, and DSB repair. Our results identify BRCA1-dependent helicase unloading as a critical, early event in ICL repair.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism
  • BRCA1 Protein / physiology*
  • Chromatin / metabolism
  • DNA Breaks, Double-Stranded
  • DNA Helicases / metabolism*
  • DNA Repair
  • DNA Replication / physiology*
  • DNA-Binding Proteins / metabolism
  • Models, Genetic*
  • Signal Transduction
  • Ubiquitin / metabolism
  • Ubiquitin / physiology
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism
  • Xenopus Proteins / physiology*
  • Xenopus laevis


  • BRCA1 Protein
  • Chromatin
  • DNA-Binding Proteins
  • Ubiquitin
  • Xenopus Proteins
  • DNA Helicases