title: In vivo dissection of the chromosome condensation machinery: reversibility of condensation distinguishes contributions of condensin and cohesin.
abstract: The machinery mediating chromosome condensation is poorly understood. To begin to dissect the in vivo function(s) of individual components, we monitored mitotic chromosome structure in mutants of condensin, cohesin, histone H3, and topoisomerase II (topo II). In budding yeast, both condensation establishment and maintenance require all of the condensin subunits, but not topo II activity or phospho-histone H3. Structural maintenance of chromosome (SMC) protein 2, as well as each of the three non-SMC proteins (Ycg1p, Ycs4p, and Brn1p), was required for chromatin binding of the condensin complex in vivo. Using reversible condensin alleles, we show that chromosome condensation does not involve an irreversible modification of condensin or chromosomes. Finally, we provide the first evidence of a mechanistic link between condensin and cohesin function. A model discussing the functional interplay between cohesin and condensin is presented.
authors.affiliation: Department of Medical Genetics and Microbiology, University of Toronto, Toronto, ON M5S 1A8, Canada. brigitte.lavoie@utoronto.ca
authors.forename: Brigitte D
authors.initials: BD
authors.lastname: Lavoie
authors.forename: Eileen
authors.initials: E
authors.lastname: Hogan
authors.forename: Douglas
authors.initials: D
authors.lastname: Koshland
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002470:Cell Survival / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation / Q000502:physiology*; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins; D006657:Histones / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D046912:Multiprotein Complexes; D009154:Mutation / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins
chemical_list: D000251:Adenosine Triphosphatases; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004250:DNA Topoisomerases, Type II; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006657:Histones; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins; C090455:SMC2 protein, S cerevisiae; C108312:condensin complexes