Reconstitution of recombination-associated DNA synthesis with human proteins

Nucleic Acids Res. 2013 May;41(9):4913-25. doi: 10.1093/nar/gkt192. Epub 2013 Mar 27.

Abstract

The repair of DNA breaks by homologous recombination is a high-fidelity process, necessary for the maintenance of genome integrity. Thus, DNA synthesis associated with recombinational repair must be largely error-free. In this report, we show that human DNA polymerase delta (δ) is capable of robust DNA synthesis at RAD51-mediated recombination intermediates dependent on the processivity clamp PCNA. Translesion synthesis polymerase eta (η) also extends these substrates, albeit far less processively. The single-stranded DNA binding protein RPA facilitates recombination-mediated DNA synthesis by increasing the efficiency of primer utilization, preventing polymerase stalling at specific sequence contexts, and overcoming polymerase stalling caused by topological constraint allowing the transition to a migrating D-loop. Our results support a model whereby the high-fidelity replicative DNA polymerase δ performs recombination-associated DNA synthesis, with translesion synthesis polymerases providing a supportive role as in normal replication.

Publication types

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

MeSH terms

  • DNA / biosynthesis*
  • DNA / metabolism
  • DNA Polymerase III / metabolism*
  • DNA-Directed DNA Polymerase / metabolism
  • Humans
  • Proliferating Cell Nuclear Antigen / metabolism
  • Rad51 Recombinase / metabolism
  • Recombinational DNA Repair*
  • Replication Protein A / metabolism*

Substances

  • Proliferating Cell Nuclear Antigen
  • Replication Protein A
  • DNA
  • RAD51 protein, human
  • Rad51 Recombinase
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Rad30 protein