DNA repair synthesis facilitates RAD52-mediated second-end capture during DSB repair

Mol Cell. 2008 Feb 29;29(4):510-6. doi: 10.1016/j.molcel.2007.11.037.


Homologous recombination (HR) is essential for the repair of DNA double-strand breaks (DSBs) in mitotic and meiotic cells. HR occurs through a series of steps involving DSB resection, invasion of single-stranded DNA into homologous duplex DNA to form a D loop, repair synthesis, and second-end capture. We show that DNA repair synthesis, catalyzed by human DNA polymerase eta (poleta) acting upon the priming strand of a D loop, leads to capture and annealing of the second end of a resected DSB in reactions mediated by RAD52 protein. Second-end capture products were not detected when poleta was replaced by other polymerases such as poldelta or poliota. RAD52 could not be replaced by RAD51. We also found that the RAD52-dependent reaction was stimulated by the single-strand binding protein RPA, but not by E. coli SSB. Following repair synthesis and second-end capture, de novo DNA synthesis was observed from the captured second DNA end.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA Breaks, Double-Stranded*
  • DNA Repair*
  • DNA, Single-Stranded* / chemistry
  • DNA, Single-Stranded* / genetics
  • DNA, Single-Stranded* / metabolism
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Nucleic Acid Conformation*
  • Rad51 Recombinase / genetics
  • Rad51 Recombinase / metabolism
  • Rad52 DNA Repair and Recombination Protein / genetics
  • Rad52 DNA Repair and Recombination Protein / metabolism*
  • Recombination, Genetic*
  • Replication Protein A / genetics
  • Replication Protein A / metabolism


  • DNA, Single-Stranded
  • Isoenzymes
  • Rad52 DNA Repair and Recombination Protein
  • Replication Protein A
  • RAD51 protein, human
  • Rad51 Recombinase
  • DNA-Directed DNA Polymerase
  • Rad30 protein