Remodeling of the Rad51 DNA strand-exchange protein by the Srs2 helicase

Genetics. 2013 Aug;194(4):859-72. doi: 10.1534/genetics.113.150615. Epub 2013 Jun 14.

Abstract

Homologous recombination is associated with the dynamic assembly and disassembly of DNA-protein complexes. Assembly of a nucleoprotein filament comprising ssDNA and the RecA homolog, Rad51, is a key step required for homology search during recombination. The budding yeast Srs2 DNA translocase is known to dismantle Rad51 filament in vitro. However, there is limited evidence to support the dismantling activity of Srs2 in vivo. Here, we show that Srs2 indeed disrupts Rad51-containing complexes from chromosomes during meiosis. Overexpression of Srs2 during the meiotic prophase impairs meiotic recombination and removes Rad51 from meiotic chromosomes. This dismantling activity is specific for Rad51, as Srs2 Overexpression does not remove Dmc1 (a meiosis-specific Rad51 homolog), Rad52 (a Rad51 mediator), or replication protein A (RPA; a single-stranded DNA-binding protein). Rather, RPA replaces Rad51 under these conditions. A mutant Srs2 lacking helicase activity cannot remove Rad51 from meiotic chromosomes. Interestingly, the Rad51-binding domain of Srs2, which is critical for Rad51-dismantling activity in vitro, is not essential for this activity in vivo. Our results suggest that a precise level of Srs2, in the form of the Srs2 translocase, is required to appropriately regulate the Rad51 nucleoprotein filament dynamics during meiosis.

Keywords: Srs2: Rad51: Dmc1: meiotic recombination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Chromosomes, Fungal / metabolism
  • DNA Helicases / chemistry
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Homologous Recombination
  • Mutation
  • Prophase
  • Rad51 Recombinase / chemistry
  • Rad51 Recombinase / genetics
  • Rad51 Recombinase / metabolism*
  • Rad52 DNA Repair and Recombination Protein / genetics
  • Rad52 DNA Repair and Recombination Protein / metabolism
  • Replication Protein A / genetics
  • Replication Protein A / metabolism
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Cell Cycle Proteins
  • DMC1 protein, S cerevisiae
  • DNA-Binding Proteins
  • RAD52 protein, S cerevisiae
  • RFA1 protein, S cerevisiae
  • Rad52 DNA Repair and Recombination Protein
  • Replication Protein A
  • Saccharomyces cerevisiae Proteins
  • SRS2 protein, S cerevisiae
  • RAD51 protein, S cerevisiae
  • Rad51 Recombinase
  • DNA Helicases