Mutation in Brca2 stimulates error-prone homology-directed repair of DNA double-strand breaks occurring between repeated sequences

EMBO J. 2001 Sep 3;20(17):4704-16. doi: 10.1093/emboj/20.17.4704.


Mutation of BRCA2 causes familial early onset breast and ovarian cancer. BRCA2 has been suggested to be important for the maintenance of genome integrity and to have a role in DNA repair by homology- directed double-strand break (DSB) repair. By studying the repair of a specific induced chromosomal DSB we show that loss of Brca2 leads to a substantial increase in error-prone repair by homology-directed single-strand annealing and a reduction in DSB repair by conservative gene conversion. These data demonstrate that loss of Brca2 causes misrepair of chromosomal DSBs occurring between repeated sequences by stimulating use of an error-prone homologous recombination pathway. Furthermore, loss of Brca2 causes a large increase in genome-wide error-prone repair of both spontaneous DNA damage and mitomycin C-induced DNA cross-links at the expense of error-free repair by sister chromatid recombination. This provides insight into the mechanisms that induce genome instability in tumour cells lacking BRCA2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • BRCA2 Protein
  • Breast Neoplasms / genetics
  • Cell Line
  • Cloning, Molecular
  • DNA Damage*
  • DNA Repair*
  • Drug Resistance, Neoplasm
  • Exons
  • Female
  • Genetic Markers
  • Humans
  • Mice
  • Mutagenesis, Site-Directed
  • Mutation*
  • Neoplasm Proteins / genetics*
  • Neoplasm Proteins / metabolism*
  • Ovarian Neoplasms / genetics
  • Recombinant Proteins / metabolism
  • Repetitive Sequences, Nucleic Acid
  • Restriction Mapping
  • Sequence Deletion
  • Stem Cells / cytology
  • Stem Cells / physiology
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*


  • BRCA2 Protein
  • Genetic Markers
  • Neoplasm Proteins
  • Recombinant Proteins
  • Transcription Factors