title: Biochemical reconstitution of topological DNA binding by the cohesin ring.
abstract: Cohesion between sister chromatids, mediated by the chromosomal cohesin complex, is a prerequisite for faithful chromosome segregation in mitosis. Cohesin also has vital roles in DNA repair and transcriptional regulation. The ring-shaped cohesin complex is thought to encircle sister DNA strands, but its molecular mechanism of action is poorly understood and the biochemical reconstitution of cohesin activity in vitro has remained an unattained goal. Here we reconstitute cohesin loading onto DNA using purified fission yeast cohesin and its loader complex, Mis4(Scc2)-Ssl3(Scc4) (Schizosaccharomyces pombe gene names appear throughout with their more commonly known Saccharomyces cerevisiae counterparts added in superscript). Incubation of cohesin with DNA leads to spontaneous topological loading, but this remains inefficient. The loader contacts cohesin at multiple sites around the ring circumference, including the hitherto enigmatic Psc3(Scc3) subunit, and stimulates cohesin's ATPase, resulting in efficient topological loading. The in vitro reconstitution of cohesin loading onto DNA provides mechanistic insight into the initial steps of the establishment of sister chromatid cohesion and other chromosomal processes mediated by cohesin.
authors.affiliation: Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Murayama
authors.affiliation: Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Frank
authors.initials: F
authors.lastname: Uhlmann
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D002842:Chromatids / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D000097722:Cohesins
chemical_list: D000251:Adenosine Triphosphatases; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D004268:DNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; D000097722:Cohesins; C115842:MIS4 protein, S pombe; C586267:Ssl3 protein, S pombe; C540907:psm1 protein, S pombe; C540908:psm3 protein, S pombe