Live-cell analysis of mitotic spindle formation in taxol-treated cells

Jessica E. Hornick, Jason R. Bader, Emily K. Tribble, Kayleigh Trimble, J. Scott Breunig, Elizabeth S. Halpin, Kevin T. Vaughan, Edward H. Hinchcliffe

    Research output: Contribution to journalArticlepeer-review

    46 Scopus citations

    Abstract

    Taxol functions to suppress the dynamic behavior of individual microtubules, and induces multipolar mitotic spindles. However, little is known about the mechanisms by which taxol disrupts normal bipolar spindle assembly in vivo. Using live imaging of GFP-α tubulin expressing cells, we examined spindle assembly after taxol treatment. We find that as taxol-treated cells enter mitosis, there is a dramatic redistribution of the microtubule network from the centrosomes to the cell cortex. As they align there, the cortical microtubules recruit NuMA to their embedded ends, followed by the kinesin motor HSET. These cortical microtubules then bud off to form cytasters, which fuse into multipolar spindles. Cytoplasmic dynein and dynactin do not re-localize to cortical microtubules, and disruption of dynein/dynactin interactions by over-expression of p50 "dynamitin" does not prevent cytaster formation. Taxol added well before spindle poles begin to form induces multipolarity, but taxol added after nascent spindle poles are visible - but before NEB is complete - results in bipolar spindles. Our results suggest that taxol prevents rapid transport of key components, such as NuMA, to the nascent spindle poles. The net result is loss of mitotic spindle pole cohesion, microtubule re-distribution, and cytaster formation.

    Original languageEnglish (US)
    Pages (from-to)595-613
    Number of pages19
    JournalCell Motility and the Cytoskeleton
    Volume65
    Issue number8
    DOIs
    StatePublished - Aug 2008

    Keywords

    • Asters
    • Microtubules
    • Mitosis
    • Spindle
    • Taxol

    ASJC Scopus subject areas

    • Structural Biology
    • Cell Biology

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