title: Pervasive and essential roles of the Top3-Rmi1 decatenase orchestrate recombination and facilitate chromosome segregation in meiosis.
abstract: The Bloom's helicase ortholog, Sgs1, plays central roles to coordinate the formation and resolution of joint molecule intermediates (JMs) during meiotic recombination in budding yeast. Sgs1 can associate with type-I topoisomerase Top3 and its accessory factor Rmi1 to form a conserved complex best known for its unique ability to decatenate double-Holliday junctions. Contrary to expectations, we show that the strand-passage activity of Top3-Rmi1 is required for all known functions of Sgs1 in meiotic recombination, including channeling JMs into physiological crossover and noncrossover pathways, and suppression of non-allelic recombination. We infer that Sgs1 always functions in the context of the Sgs1-Top3-Rmi1 complex to regulate meiotic recombination. In addition, we reveal a distinct late role for Top3-Rmi1 in resolving recombination-dependent chromosome entanglements to allow segregation at anaphase. Surprisingly, Sgs1 does not share this essential role of Top3-Rmi1. These data reveal an essential and pervasive role for the Top3-Rmi1 decatenase during meiosis.
authors.affiliation: Howard Hughes Medical Institute and the Departments of Microbiology & Molecular Genetics, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Shangming
authors.initials: S
authors.lastname: Tang
authors.affiliation: Howard Hughes Medical Institute and the Departments of Microbiology & Molecular Genetics, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Michelle Ka Yan
authors.initials: MKY
authors.lastname: Wu
authors.affiliation: Howard Hughes Medical Institute and the Departments of Microbiology & Molecular Genetics, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Ruoxi
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Howard Hughes Medical Institute and the Departments of Microbiology & Molecular Genetics, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA. Electronic address: nhunter@ucdavis.edu.
authors.forename: Neil
authors.initials: N
authors.lastname: Hunter
mesh_terms: D020090:Chromosome Segregation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D059765:Homologous Recombination / Q000502:physiology*; D008540:Meiosis / Q000235:genetics*; D008957:Models, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; C502206:Rmi1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C502374:TOP3 protein, S cerevisiae