Differential contributions of condensin I and condensin II to mitotic chromosome architecture in vertebrate cells.
The canonical condensin complex (henceforth condensin I) plays an essential role in mitotic chromosome assembly and segregation from yeast to humans. We report here the identification of a second condensin complex (condensin II) from vertebrate cells. Condensins I and II share the same pair of structural maintenance of chromosomes (SMC) subunits but contain different sets of non-SMC subunits. siRNA-mediated depletion of condensin I- or condensin II-specific subunits in HeLa cells produces a distinct, highly characteristic defect in chromosome morphology. Simultaneous depletion of both complexes causes the severest defect. In Xenopus egg extracts, condensin I function is predominant, but lack of condensin II results in the formation of irregularly shaped chromosomes. Condensins I and II show different distributions along the axis of chromosomes assembled in vivo and in vitro. We propose that the two condensin complexes make distinct mechanistic contributions to mitotic chromosome architecture in vertebrate cells.
Ono
Takao
T
Cold Spring Harbor Laboratory, One Bungtown Road, PO Box 100, Cold Spring Harbor, NY 11724, USA.
Losada
Ana
A
Hirano
Michiko
M
Myers
Michael P
MP
Neuwald
Andrew F
AF
Hirano
Tatsuya
T
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002875:Chromosomes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014982:Xenopus laevis
D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D020033:Protein Isoforms; D021122:Protein Subunits; D034741:RNA, Small Interfering; C108312:condensin complexes; D000251:Adenosine Triphosphatases