Condensin and Repo-Man-PP1 co-operate in the regulation of chromosome architecture during mitosis.
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.
Vagnarelli
Paola
P
Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Swann Building, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK.
Hudson
Damien F
DF
Ribeiro
Susana A
SA
Trinkle-Mulcahy
Laura
L
Spence
Jennifer M
JM
Lai
Fan
F
Farr
Christine J
CJ
Lamond
Angus I
AI
Earnshaw
William C
WC
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
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