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dc.contributor.authorTirnauer, Jennifer S.  Concept link
dc.contributor.authorSalmon, Edward D.  Concept link
dc.contributor.authorMitchison, Timothy J.  Concept link
dc.date.accessioned2007-12-20T18:29:54Z
dc.date.available2007-12-20T18:29:54Z
dc.date.issued2004-02-06
dc.identifier.citationMolecular Biology of the Cell 15 (2004): 1776-1784en
dc.identifier.urihttps://hdl.handle.net/1912/1937
dc.descriptionAuthor Posting. © American Society for Cell Biology, 2004. This article is posted here by permission of American Society for Cell Biology for personal use, not for redistribution. The definitive version was published in Molecular Biology of the Cell 15 (2004): 1776-1784, doi:10.1091/mbc.E03-11-0824.en
dc.description.abstractMicrotubule dynamics underlie spindle assembly, yet we do not know how the spindle environment affects these dynamics. We developed methods for measuring two key parameters of microtubule plus-end dynamic instability in Xenopus egg extract spindles. To measure plus-end polymerization rates and localize growing plus ends, we used fluorescence confocal imaging of EB1. This revealed plus-end polymerization throughout the spindle at ~11 µm/min, similar to astral microtubules, suggesting polymerization velocity is not regionally regulated by the spindle. The ratio of EB1 to microtubule fluorescence revealed an enrichment of polymerizing ends near the spindle middle, indicating enhanced nucleation or rescue there. We measured depolymerization rates by creating a front of synchronized depolymerization in spindles severed with microneedles. This front could be tracked by polarization and fluorescence microscopy as it advanced from each cut edge toward the associated pole. Both imaging modalities revealed rapid depolymerization (~30 µm/min) superimposed on a subset of microtubules stable to depolymerization. Larger spindle fragments contained a higher percentage of stable microtubules, which we believe were oriented with their minus ends facing the cut. Depolymerization was blocked by the potent microtubule stabilizing agent hexylene glycol, but was unaffected by {alpha}-MCAK antibody and AMPPNP, which block catastrophe and kinesin motility, respectively. These measurements move us closer to understanding the complete life history of a spindle microtubule.en
dc.description.sponsorshipThis work was supported by a Universal Imaging Corporation Fellowship to the Cell Division Group at the Marine Biological Laboratories, Woods Hole, MA; and by National Institutes of Health Grants DK02578 and DK58766 (to J.S.T.), GM- 24364 and GM-60678 (to E.D.S.), and GM-39565 (to T.J.M.).en
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dc.language.isoen_USen
dc.publisherAmerican Society for Cell Biologyen
dc.relation.urihttps://doi.org/10.1091/mbc.E03-11-0824
dc.titleMicrotubule plus-end dynamics in Xenopus egg extract spindlesen
dc.typeArticleen
dc.identifier.doi10.1091/mbc.E03-11-0824


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