PCNA is required for initiation of recombination-associated DNA synthesis by DNA polymerase delta

Mol Cell. 2009 Nov 25;36(4):704-13. doi: 10.1016/j.molcel.2009.09.036.


Genetic recombination ensures proper chromosome segregation during meiosis and is essential for genome stability and tumor suppression. DNA synthesis after Rad51-mediated DNA strand invasion is a crucial step during recombination. PCNA is known as the processivity clamp for DNA polymerases. Here, we report the surprising observation that PCNA is specifically required to initiate recombination-associated DNA synthesis in the extension of the 3' end of the invading strand in a D loop. We show using a reconstituted system of yeast Rad51, Rad54, RPA, PCNA, RFC, and DNA polymerase delta that loading of PCNA by RFC targets DNA polymerase delta to the D loop formed by Rad51 protein, allowing efficient utilization of the invading 3' end and processive DNA synthesis. We conclude that PCNA has a specific role in the initiation of recombination-associated DNA synthesis and that DNA polymerase delta promotes recombination-associated DNA synthesis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • DNA / biosynthesis*
  • DNA Helicases
  • DNA Polymerase III / metabolism*
  • DNA Repair Enzymes / metabolism
  • DNA-Directed DNA Polymerase / metabolism
  • Nucleic Acid Conformation
  • Proliferating Cell Nuclear Antigen / metabolism*
  • Rad51 Recombinase / metabolism
  • Recombination, Genetic*
  • Replication Protein C / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins / metabolism


  • Proliferating Cell Nuclear Antigen
  • Saccharomyces cerevisiae Proteins
  • DNA
  • Rad51 Recombinase
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Rad30 protein
  • RAD54 protein, S cerevisiae
  • DNA Helicases
  • Replication Protein C
  • DNA Repair Enzymes