Homologous recombination, but not DNA repair, is reduced in vertebrate cells deficient in RAD52

Mol Cell Biol. 1998 Nov;18(11):6430-5. doi: 10.1128/MCB.18.11.6430.


Rad52 plays a pivotal role in double-strand break (DSB) repair and genetic recombination in Saccharomyces cerevisiae, where mutation of this gene leads to extreme X-ray sensitivity and defective recombination. Yeast Rad51 and Rad52 interact, as do their human homologues, which stimulates Rad51-mediated DNA strand exchange in vitro, suggesting that Rad51 and Rad52 act cooperatively. To define the role of Rad52 in vertebrates, we generated RAD52(-/-) mutants of the chicken B-cell line DT40. Surprisingly, RAD52(-/-) cells were not hypersensitive to DNA damages induced by gamma-irradiation, methyl methanesulfonate, or cis-platinum(II)diammine dichloride (cisplatin). Intrachromosomal recombination, measured by immunoglobulin gene conversion, and radiation-induced Rad51 nuclear focus formation, which is a putative intermediate step during recombinational repair, occurred as frequently in RAD52(-/-) cells as in wild-type cells. Targeted integration frequencies, however, were consistently reduced in RAD52(-/-) cells, showing a clear role for Rad52 in genetic recombination. These findings reveal striking differences between S. cerevisiae and vertebrates in the functions of RAD51 and RAD52.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / metabolism*
  • Cell Line
  • Cell Survival / drug effects
  • Chickens
  • Cisplatin / pharmacology
  • DNA Repair / genetics*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Fluorescent Antibody Technique
  • Gene Targeting
  • Immunoglobulin M / immunology
  • Methyl Methanesulfonate / pharmacology
  • Mutagens / pharmacology
  • Recombination, Genetic / genetics*
  • Transfection / standards
  • X-Rays


  • DNA-Binding Proteins
  • Immunoglobulin M
  • Mutagens
  • Methyl Methanesulfonate
  • Cisplatin