title: Mitotic chromosomes are compacted laterally by KIF4 and condensin and axially by topoisomerase IIα.
abstract: Mitotic chromosome formation involves a relatively minor condensation of the chromatin volume coupled with a dramatic reorganization into the characteristic "X" shape. Here we report results of a detailed morphological analysis, which revealed that chromokinesin KIF4 cooperated in a parallel pathway with condensin complexes to promote the lateral compaction of chromatid arms. In this analysis, KIF4 and condensin were mutually dependent for their dynamic localization on the chromatid axes. Depletion of either caused sister chromatids to expand and compromised the "intrinsic structure" of the chromosomes (defined in an in vitro assay), with loss of condensin showing stronger effects. Simultaneous depletion of KIF4 and condensin caused complete loss of chromosome morphology. In these experiments, topoisomerase IIα contributed to shaping mitotic chromosomes by promoting the shortening of the chromatid axes and apparently acting in opposition to the actions of KIF4 and condensins. These three proteins are major determinants in shaping the characteristic mitotic chromosome morphology.
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, Scotland, UK.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Samejima
authors.forename: Itaru
authors.initials: I
authors.lastname: Samejima
authors.forename: Paola
authors.initials: P
authors.lastname: Vagnarelli
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ogawa
authors.forename: Giulia
authors.initials: G
authors.lastname: Vargiu
authors.forename: David A
authors.initials: DA
authors.lastname: Kelly
authors.forename: Flavia
authors.initials: F
authors.lastname: de Lima Alves
authors.forename: Alastair
authors.initials: A
authors.lastname: Kerr
authors.forename: Lydia C
authors.initials: LC
authors.lastname: Green
authors.forename: Damien F
authors.initials: DF
authors.lastname: Hudson
authors.forename: Shinya
authors.initials: S
authors.lastname: Ohta
authors.forename: Carol A
authors.initials: CA
authors.lastname: Cooke
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Farr
authors.forename: Juri
authors.initials: J
authors.lastname: Rappsilber
authors.forename: William C
authors.initials: WC
authors.lastname: Earnshaw
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000951:Antigens, Neoplasm / Q000378:metabolism*; D002645:Chickens; D002842:Chromatids / Q000378:metabolism; D002875:Chromosomes / Q000378:metabolism*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; C092349:chromokinesin; C108312:condensin complexes; D000251:Adenosine Triphosphatases; D016547:Kinesins; D004250:DNA Topoisomerases, Type II