title: Condensin and Repo-Man-PP1 co-operate in the regulation of chromosome architecture during mitosis.
abstract: The reversible condensation of chromosomes during cell division remains a classic problem in cell biology. Condensation requires the condensin complex in certain experimental systems, but not in many others. Anaphase chromosome segregation almost always fails in condensin-depleted cells, leading to the formation of prominent chromatin bridges and cytokinesis failure. Here, live-cell analysis of chicken DT40 cells bearing a conditional knockout of condensin subunit SMC2 revealed that condensin-depleted chromosomes abruptly lose their compact architecture during anaphase and form massive chromatin bridges. The compact chromosome structure can be preserved and anaphase chromosome segregation rescued by preventing the targeting subunit Repo-Man from recruiting protein phosphatase 1 (PP1) to chromatin at anaphase onset. This study identifies an activity critical for mitotic chromosome structure that is inactivated by Repo-Man-PP1 during anaphase. This activity, provisionally termed 'regulator of chromosome architecture' (RCA), cooperates with condensin to preserve the characteristic chromosome architecture during mitosis.
authors.affiliation: Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Swann Building, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK.
authors.forename: Paola
authors.initials: P
authors.lastname: Vagnarelli
authors.forename: Damien F
authors.initials: DF
authors.lastname: Hudson
authors.forename: Susana A
authors.initials: SA
authors.lastname: Ribeiro
authors.forename: Laura
authors.initials: L
authors.lastname: Trinkle-Mulcahy
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Spence
authors.forename: Fan
authors.initials: F
authors.lastname: Lai
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Farr
authors.forename: Angus I
authors.initials: AI
authors.lastname: Lamond
authors.forename: William C
authors.initials: WC
authors.lastname: Earnshaw
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000705:Anaphase; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002645:Chickens; D002843:Chromatin / Q000378:metabolism; D020090:Chromosome Segregation; D002875:Chromosomes / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008938:Mitosis; D046912:Multiprotein Complexes / Q000378:metabolism*; D009687:Nuclear Proteins; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D054645:Protein Phosphatase 1; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: C509224:CDCA2 protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; C108312:condensin complexes; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D000251:Adenosine Triphosphatases