Rmi1 stimulates decatenation of double Holliday junctions during dissolution by Sgs1-Top3

Nat Struct Mol Biol. 2010 Nov;17(11):1377-82. doi: 10.1038/nsmb.1919. Epub 2010 Oct 10.

Abstract

A double Holliday junction (dHJ) is a central intermediate of homologous recombination that can be processed to yield crossover or non-crossover recombination products. To preserve genomic integrity, cells possess mechanisms to avoid crossing over. We show that Saccharomyces cerevisiae Sgs1 and Top3 proteins are sufficient to migrate and disentangle a dHJ to produce exclusively non-crossover recombination products, in a reaction termed "dissolution." We show that Rmi1 stimulates dHJ dissolution at low Sgs1-Top3 protein concentrations, although it has no effect on the initial rate of Holliday junction (HJ) migration. Rmi1 serves to stimulate DNA decatenation, removing the last linkages between the repaired and template DNA molecules. Dissolution of a dHJ is a highly efficient and concerted alternative to nucleolytic resolution that prevents crossing over of chromosomes during recombinational DNA repair in mitotic cells and thereby contributes to genomic integrity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • DNA, Cruciform / metabolism*
  • DNA, Fungal / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • RecQ Helicases / genetics
  • RecQ Helicases / metabolism
  • RecQ Helicases / physiology*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology*

Substances

  • DNA, Cruciform
  • DNA, Fungal
  • DNA-Binding Proteins
  • Rmi1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • TOP3 protein, S cerevisiae
  • SGS1 protein, S cerevisiae
  • RecQ Helicases