A bidirectional kinesin motor in live Drosophila embryos.

Published

Journal Article

Spindle assembly and elongation involve poleward and away-from-the-pole forces produced by microtubule dynamics and spindle-associated motors. Here, we show that a bidirectional Drosophila Kinesin-14 motor that moves either to the microtubule plus or minus end in vitro unexpectedly causes only minor spindle defects in vivo. However, spindles of mutant embryos are longer than wild type, consistent with increased plus-end motor activity. Strikingly, suppressing spindle dynamics by depriving embryos of oxygen causes the bidirectional motor to show increased accumulation at distal or plus ends of astral microtubules relative to wild type, an effect not observed for a mutant motor defective in motility. Increased motor accumulation at microtubule plus ends may be due to increased slow plus-end movement of the bidirectional motor under hypoxia, caused by perturbation of microtubule dynamics or inactivation of the only other known Drosophila minus-end spindle motor, cytoplasmic dynein. Negative-stain electron microscopy images are consistent with highly cooperative motor binding to microtubules, and gliding assays show dependence on motor density for motility. Mutant effects of the bidirectional motor on spindle function may be suppressed under normal conditions by motor: motor interactions and minus-end movement induced by spindle dynamics. These forces may also bias wild-type motor movement toward microtubule minus ends in live cells. Our findings link motor : motor interactions to function in vivo by showing that motor density, together with cellular dynamics, may influence motor function in live cells.

Full Text

Duke Authors

Cited Authors

  • Sciambi, CJ; Komma, DJ; Sköld, HN; Hirose, K; Endow, SA

Published Date

  • November 2005

Published In

Volume / Issue

  • 6 / 11

Start / End Page

  • 1036 - 1046

PubMed ID

  • 16190984

Pubmed Central ID

  • 16190984

International Standard Serial Number (ISSN)

  • 1398-9219

Digital Object Identifier (DOI)

  • 10.1111/j.1600-0854.2005.00343.x

Language

  • eng

Conference Location

  • England