Open AccessLive‐cell analysis of mitotic spindle formation in taxol‐treated cells
Author(s) -
Hornick Jessica E.,
Bader Jason R.,
Tribble Emily K.,
Trimble Kayleigh,
Breunig J. Scott,
Halpin Elizabeth S.,
Vaughan Kevin T.,
Hinchcliffe Edward H.
Publication year - 2008
Publication title -
cell motility and the cytoskeleton
Language(s) - English
Resource type - Journals
eISSN - 1097-0169
pISSN - 0886-1544
DOI - 10.1002/cm.20283
Subject(s) - microtubule , biology , microbiology and biotechnology , dynactin , centrosome , dynein , spindle apparatus , mitosis , spindle pole body , microtubule organizing center , astral microtubules , kinesin , microtubule nucleation , cell division , cell , cell cycle , genetics
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 re‐distribution 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. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.