Time-lapse video microscopy analysis reveals astral microtubule detachment in the yeast spindle pole mutant cnm67

Hoepfner, D. and Brachat, A. and Philippsen, P.. (2000) Time-lapse video microscopy analysis reveals astral microtubule detachment in the yeast spindle pole mutant cnm67. Molecular Biology of the Cell, 11 (4). pp. 1197-1211.

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Official URL: http://edoc.unibas.ch/dok/A5257607

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Saccharomyces cerevisiae cnm67Delta cells lack the spindle pole body (SPB) outer plaque, the main attachment site for astral (cytoplasmic) microtubules, leading to frequent nuclear segregation failure. We monitored dynamics of green fluorescent protein-labeled nuclei and microtubules over several cell cycles. Early nuclear migration steps such as nuclear positioning and spindle orientation were slightly affected, but late phases such as rapid oscillations and insertion of the anaphase nucleus into the bud neck were mostly absent. Analyzes of microtubule dynamics revealed normal behavior of the nuclear spindle but frequent detachment of astral microtubules after SPB separation. Concomitantly, Spc72 protein, the cytoplasmic anchor for the gamma-tubulin complex, was partially lost from the SPB region with dynamics similar to those observed for microtubules. We postulate that in cnm67Delta cells Spc72-gamma-tubulin complex-capped astral microtubules are released from the half-bridge upon SPB separation but fail to be anchored to the cytoplasmic side of the SPB because of the absence of an outer plaque. However, successful nuclear segregation in cnm67Delta cells can still be achieved by elongation forces of spindles that were correctly oriented before astral microtubule detachment by action of Kip3/Kar3 motors. Interestingly, the first nuclear segregation in newborn diploid cells never fails, even though astral microtubule detachment occurs.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Applied Microbiology (Philippsen)
UniBasel Contributors:Philippsen, Peter
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Cell Biology
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:07 Nov 2017 07:59
Deposited On:22 Mar 2012 13:18

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