title: The condensin complex is required for proper spindle assembly and chromosome segregation in Xenopus egg extracts.
abstract: Chromosome condensation is required for the physical resolution and segregation of sister chromatids during cell division, but the precise role of higher order chromatin structure in mitotic chromosome functions is unclear. Here, we address the role of the major condensation machinery, the condensin complex, in spindle assembly and function in Xenopus laevis egg extracts. Immunodepletion of condensin inhibited microtubule growth and organization around chromosomes, reducing the percentage of sperm nuclei capable of forming spindles, and causing dramatic defects in anaphase chromosome segregation. Although the motor CENP-E was recruited to kinetochores pulled poleward during anaphase, the disorganized chromosome mass was not resolved. Inhibition of condensin function during anaphase also inhibited chromosome segregation, indicating its continuous requirement. Spindle assembly around DNA-coated beads in the absence of kinetochores was also impaired upon condensin inhibition. These results support an important role for condensin in establishing chromosomal architecture necessary for proper spindle assembly and chromosome segregation.
authors.affiliation: Deparmet of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Wignall
authors.forename: Renee
authors.initials: R
authors.lastname: Deehan
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Maresca
authors.forename: Rebecca
authors.initials: R
authors.lastname: Heald
mesh_terms: D000251:Adenosine Triphosphatases / Q000172:deficiency* / Q000235:genetics; D000705:Anaphase / Q000235:genetics; D000818:Animals; D002455:Cell Division / Q000502:physiology*; D002457:Cell Extracts; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics; D005057:Eukaryotic Cells / Q000378:metabolism*; D005260:Female; D018386:Kinetochores / Q000378:metabolism; D046911:Macromolecular Substances; D008297:Male; D008870:Microtubules / Q000378:metabolism; D046912:Multiprotein Complexes; D009865:Oocytes; D021381:Protein Transport / Q000235:genetics; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D002457:Cell Extracts; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; C068688:centromere protein E; C108312:condensin complexes; D000251:Adenosine Triphosphatases