Dynamic changes of BRCA1 subnuclear location and phosphorylation state are initiated by DNA damage

Cell. 1997 Aug 8;90(3):425-35. doi: 10.1016/s0092-8674(00)80503-6.


BRCA1 localizes to discrete nuclear foci (dots) during S phase. Hydroxyurea-mediated DNA synthesis arrest of S phase MCF7 cells led to a loss of BRCA1 from these structures. Ultraviolet light, mitomycin C, or gamma irradiation produced a similar effect but with no concurrent arrest of DNA synthesis. BARD1 and Rad51, two proteins associated with the BRCA1 dots, behaved similarly. Loss of the BRCA1 foci was accompanied by a specific, dose-dependent change(s) in the state of BRCA1 phosphorylation. Three distinct DNA damaging agents preferentially induced this change in S phase. The S phase BRCA1 phosphorylation response to DNA damage occurred in cells lacking, respectively, two DNA damage-sensing protein kinases, DNA-PK and Atm, implying that neither plays a prime role in this process. Finally, after BRCA1 dot dispersal, BRCA1, BARD1, and Rad51 accumulated, focally, on PCNA+ replication structures, implying an interaction of BRCA1/BARD1/Rad51 containing complexes with damaged, replicating DNA. Taken together, the data imply that the BRCA1 S phase foci are dynamic physiological elements, responsive to DNA damage, and that BRCA1-containing multiprotein complexes participate in a replication checkpoint response.

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins
  • BRCA1 Protein / metabolism*
  • Breast Neoplasms
  • Cell Cycle
  • Cell Cycle Proteins
  • Cell Nucleus / metabolism*
  • Cell Nucleus / ultrastructure
  • DNA Damage*
  • DNA Replication / drug effects
  • DNA Replication / radiation effects
  • DNA-Activated Protein Kinase
  • DNA-Binding Proteins*
  • Female
  • Humans
  • Hydroxyurea / pharmacology
  • Leucine Zippers
  • Microscopy, Confocal
  • Nuclear Proteins
  • Phosphorylation
  • Proliferating Cell Nuclear Antigen / analysis
  • Protein-Serine-Threonine Kinases / deficiency
  • Protein-Serine-Threonine Kinases / metabolism
  • Proteins / metabolism
  • S Phase
  • Tumor Cells, Cultured
  • Tumor Suppressor Proteins
  • Ultraviolet Rays


  • BRCA1 Protein
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Proliferating Cell Nuclear Antigen
  • Proteins
  • Tumor Suppressor Proteins
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • DNA-Activated Protein Kinase
  • PRKDC protein, human
  • Protein-Serine-Threonine Kinases
  • Hydroxyurea