title: Increased mobility of double-strand breaks requires Mec1, Rad9 and the homologous recombination machinery.
abstract: Chromatin mobility is thought to facilitate homology search during homologous recombination and to shift damage either towards or away from specialized repair compartments. However, unconstrained mobility of double-strand breaks could also promote deleterious chromosomal translocations. Here we use live time-lapse fluorescence microscopy to track the mobility of damaged DNA in budding yeast. We found that a Rad52-YFP focus formed at an irreparable double-strand break moves in a larger subnuclear volume than the undamaged locus. In contrast, Rad52-YFP bound at damage arising from a protein-DNA adduct shows no increase in movement. Mutant analysis shows that enhanced double-strand-break mobility requires Rad51, the ATPase activity of Rad54, the ATR homologue Mec1 and the DNA-damage-response mediator Rad9. Consistent with a role for movement in the homology-search step of homologous recombination, we show that recombination intermediates take longer to form in cells lacking Rad9.
authors.affiliation: Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Dion
authors.forename: Véronique
authors.initials: V
authors.lastname: Kalck
authors.forename: Chihiro
authors.initials: C
authors.lastname: Horigome
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Towbin
authors.forename: Susan M
authors.initials: SM
authors.lastname: Gasser
mesh_terms: D018797:Cell Cycle Proteins / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism; D004249:DNA Damage; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D008856:Microscopy, Fluorescence; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases