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Contrasting roles of condensin I and condensin II in mitotic chromosome formation.

Authors :
Green, Lydia C.
Kalitsis, Paul
Chang, Tsz M.
Cipetic, Miri
Ji Hun Kim
Marshall, Owen
Turnbull, Lynne
Whitchurch, Cynthia B.
Vagnarelli, Paola
Samejima, Kumiko
Earnshaw, William C.
Choo, K. H. Andy
Hudson, Damien F.
Source :
Journal of Cell Science; 3/15/2012, Vol. 125 Issue 6, p1591-1604, 14p
Publication Year :
2012

Abstract

In vertebrates, two condensin complexes exist, condensin I and condensin II, which have differing but unresolved roles in organizing mitotic chromosomes. To dissect accurately the role of each complex in mitosis, we have made and studied the first vertebrate conditional knockouts of the genes encoding condensin I subunit CAP-H and condensin II subunit CAP-D3 in chicken DT40 cells. Live-cell imaging reveals highly distinct segregation defects. CAP-D3 (condensin II) knockout results in masses of chromatincontaining anaphase bridges. CAP-H (condensin I)-knockout anaphases have a more subtle defect, with chromatids showing fine chromatin fibres that are associated with failure of cytokinesis and cell death. Super-resolution microscopy reveals that condensin-Idepleted mitotic chromosomes are wider and shorter, with a diffuse chromosome scaffold, whereas condensin-II-depleted chromosomes retain a more defined scaffold, with chromosomes more stretched and seemingly lacking in axial rigidity. We conclude that condensin II is required primarily to provide rigidity by establishing an initial chromosome axis around which condensin I can arrange loops of chromatin. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219533
Volume :
125
Issue :
6
Database :
Complementary Index
Journal :
Journal of Cell Science
Publication Type :
Academic Journal
Accession number :
88912360
Full Text :
https://doi.org/10.1242/jcs.097790