Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Microtubule plus-end dynamics in Xenopus egg extract spindles.
Tirnauer JS
,
Salmon ED
,
Mitchison TJ
.
???displayArticle.abstract??? Microtubule 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 approximately 11 microm/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 ( approximately 30 microm/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.
Belmont,
Identification of a protein that interacts with tubulin dimers and increases the catastrophe rate of microtubules.
1996, Pubmed,
Xenbase
Belmont,
Identification of a protein that interacts with tubulin dimers and increases the catastrophe rate of microtubules.
1996,
Pubmed
,
Xenbase
Carazo-Salas,
Ran-GTP coordinates regulation of microtubule nucleation and dynamics during mitotic-spindle assembly.
2001,
Pubmed
,
Xenbase
Desai,
The use of Xenopus egg extracts to study mitotic spindle assembly and function in vitro.
1999,
Pubmed
,
Xenbase
Desai,
Microtubule polymerization dynamics.
1997,
Pubmed
Forer,
Spindle birefringence of isolated mitotic apparatus: further evidence for two birefringent spindle components.
1976,
Pubmed
Harris,
Conditions for assembly of tubulin-based structures in unfertilized sea urchin eggs. Spirals, monasters and cytasters.
1992,
Pubmed
Hayden,
Kinetochores capture astral microtubules during chromosome attachment to the mitotic spindle: direct visualization in live newt lung cells.
1990,
Pubmed
Heald,
Spindle assembly in Xenopus egg extracts: respective roles of centrosomes and microtubule self-organization.
1997,
Pubmed
,
Xenbase
Hyman,
Preparation of modified tubulins.
1991,
Pubmed
Inoué,
Force generation by microtubule assembly/disassembly in mitosis and related movements.
1995,
Pubmed
Kalab,
Visualization of a Ran-GTP gradient in interphase and mitotic Xenopus egg extracts.
2002,
Pubmed
,
Xenbase
Karsenti,
The mitotic spindle: a self-made machine.
2001,
Pubmed
,
Xenbase
Kinoshita,
Reconstitution of physiological microtubule dynamics using purified components.
2001,
Pubmed
,
Xenbase
Leslie,
Spindle microtubule dynamics following ultraviolet-microbeam irradiations of mitotic diatoms.
1984,
Pubmed
Maddox,
Direct observation of microtubule dynamics at kinetochores in Xenopus extract spindles: implications for spindle mechanics.
2003,
Pubmed
,
Xenbase
Mastronarde,
Interpolar spindle microtubules in PTK cells.
1993,
Pubmed
Mitchison,
Properties of the kinetochore in vitro. II. Microtubule capture and ATP-dependent translocation.
1985,
Pubmed
Nicklas,
Mechanically cut mitotic spindles: clean cuts and stable microtubules.
1989,
Pubmed
Nédélec,
Self-organisation and forces in the microtubule cytoskeleton.
2003,
Pubmed
Parsons,
Microtubule assembly in clarified Xenopus egg extracts.
1997,
Pubmed
,
Xenbase
Rieder,
Mitosis through the microscope: advances in seeing inside live dividing cells.
2003,
Pubmed
Sawin,
Poleward microtubule flux mitotic spindles assembled in vitro.
1991,
Pubmed
,
Xenbase
Shelden,
Observation and quantification of individual microtubule behavior in vivo: microtubule dynamics are cell-type specific.
1993,
Pubmed
Spurck,
Ultraviolet microbeam irradiations of epithelial and spermatocyte spindles suggest that forces act on the kinetochore fibre and are not generated by its disassembly.
1997,
Pubmed
Spurck,
UV microbeam irradiations of the mitotic spindle. II. Spindle fiber dynamics and force production.
1990,
Pubmed
Tirnauer,
EB1-microtubule interactions in Xenopus egg extracts: role of EB1 in microtubule stabilization and mechanisms of targeting to microtubules.
2002,
Pubmed
,
Xenbase
Tirnauer,
EB1 targets to kinetochores with attached, polymerizing microtubules.
2002,
Pubmed
Tournebize,
Control of microtubule dynamics by the antagonistic activities of XMAP215 and XKCM1 in Xenopus egg extracts.
2000,
Pubmed
,
Xenbase
Tran,
A metastable intermediate state of microtubule dynamic instability that differs significantly between plus and minus ends.
1997,
Pubmed
Trieselmann,
Ran localizes around the microtubule spindle in vivo during mitosis in Drosophila embryos.
2002,
Pubmed
Vallotton,
Recovery, visualization, and analysis of actin and tubulin polymer flow in live cells: a fluorescent speckle microscopy study.
2003,
Pubmed
,
Xenbase
Vasquez,
XMAP from Xenopus eggs promotes rapid plus end assembly of microtubules and rapid microtubule polymer turnover.
1994,
Pubmed
,
Xenbase
Walker,
Asymmetric behavior of severed microtubule ends after ultraviolet-microbeam irradiation of individual microtubules in vitro.
1989,
Pubmed
Waterman-Storer,
Fluorescent speckle microscopy, a method to visualize the dynamics of protein assemblies in living cells.
1998,
Pubmed
,
Xenbase
Waters,
Pathways of spindle assembly.
1997,
Pubmed
Wilde,
Ran stimulates spindle assembly by altering microtubule dynamics and the balance of motor activities.
2001,
Pubmed
,
Xenbase