title: Saccharomyces cerevisiae Dmc1 and Rad51 proteins preferentially function with Tid1 and Rad54 proteins, respectively, to promote DNA strand invasion during genetic recombination.
abstract: The Saccharomyces cerevisiae Dmc1 and Tid1 proteins are required for the pairing of homologous chromosomes during meiotic recombination. This pairing is the precursor to the formation of crossovers between homologs, an event that is necessary for the accurate segregation of chromosomes. Failure to form crossovers can have serious consequences and may lead to chromosomal imbalance. Dmc1, a meiosis-specific paralog of Rad51, mediates the pairing of homologous chromosomes. Tid1, a Rad54 paralog, although not meiosis-specific, interacts with Dmc1 and promotes crossover formation between homologs. In this study, we show that purified Dmc1 and Tid1 interact physically and functionally. Dmc1 forms stable nucleoprotein filaments that can mediate DNA strand invasion. Tid1 stimulates Dmc1-mediated formation of joint molecules. Under conditions optimal for Dmc1 reactions, Rad51 is specifically stimulated by Rad54, establishing that Dmc1-Tid1 and Rad51-Rad54 function as specific pairs. Physical interaction studies show that specificity in function is not dictated by direct interactions between the proteins. Our data are consistent with the hypothesis that Rad51-Rad54 function together to promote intersister DNA strand exchange, whereas Dmc1-Tid1 tilt the bias toward interhomolog DNA strand exchange.
authors: Department of Microbiology, University of California, Davis, California 95616, USA.
authors: Amitabh V
authors: AV
authors: Nimonkar
authors: Christopher C
authors: CC
authors: Dombrowski
authors: Joseph S
authors: JS
authors: Siino
authors: Alicja Z
authors: AZ
authors: Stasiak
authors: Andrzej
authors: A
authors: Stasiak
authors: Stephen C
authors: SC
authors: Kowalczykowski
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D015825:Chromosomes, Fungal / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism*; D026942:DNA Topoisomerases / Q000235:genetics / Q000378:metabolism*; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008540:Meiosis / Q000502:physiology; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C513033:DMC1 protein, S cerevisiae; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D026942:DNA Topoisomerases; C541336:RDH54 protein, S cerevisiae; D045643:DNA Repair Enzymes