Limits...
A microtubule-destabilizing kinesin motor regulates spindle length and anchoring in oocytes.

Zou J, Hallen MA, Yankel CD, Endow SA - J. Cell Biol. (2008)

Bottom Line: We frequently observe the pole bodies attached to cortical microtubules, indicating that KLP10A could mediate spindle anchoring to the cortex via cortical microtubules.A dominant-negative klp10A mutant shows both reoriented and shorter oocyte spindles, implying that, unexpectedly, KLP10A may stabilize rather than destabilize microtubules, regulating spindle length and positioning the oocyte spindle.By altering microtubule dynamics, KLP10A could promote spindle reorientation upon oocyte activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.

ABSTRACT
The kinesin-13 motor, KLP10A, destabilizes microtubules at their minus ends in mitosis and binds to polymerizing plus ends in interphase, regulating spindle and microtubule dynamics. Little is known about kinesin-13 motors in meiosis. In this study, we report that KLP10A localizes to the unusual pole bodies of anastral Drosophila melanogaster oocyte meiosis I spindles as well as spindle fibers, centromeres, and cortical microtubules. We frequently observe the pole bodies attached to cortical microtubules, indicating that KLP10A could mediate spindle anchoring to the cortex via cortical microtubules. Oocytes treated with drugs that suppress microtubule dynamics exhibit spindles that are reoriented more vertically to the cortex than untreated controls. A dominant-negative klp10A mutant shows both reoriented and shorter oocyte spindles, implying that, unexpectedly, KLP10A may stabilize rather than destabilize microtubules, regulating spindle length and positioning the oocyte spindle. By altering microtubule dynamics, KLP10A could promote spindle reorientation upon oocyte activation.

Show MeSH
KLP10A binds to both spindle poles and cortical microtubules. (A) Meiosis I spindles in fixed klp10A-gfp oocytes show pole bodies attached to cortical microtubules (arrows). (B) Fixed gfp–α-tubulin or klp10A-gfp oocytes treated with microtubule-destabilizing/stabilizing drugs show changes in GFP–α-tubulin (top) or KLP10A-GFP cortical microtubule signals (middle) and spindle length (bottom). Taxol causes increased KLP10A-GFP spindle fluorescence (arrows). Bars, 5 μm (A, two images at right, 3 μm).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2234233&req=5

fig2: KLP10A binds to both spindle poles and cortical microtubules. (A) Meiosis I spindles in fixed klp10A-gfp oocytes show pole bodies attached to cortical microtubules (arrows). (B) Fixed gfp–α-tubulin or klp10A-gfp oocytes treated with microtubule-destabilizing/stabilizing drugs show changes in GFP–α-tubulin (top) or KLP10A-GFP cortical microtubule signals (middle) and spindle length (bottom). Taxol causes increased KLP10A-GFP spindle fluorescence (arrows). Bars, 5 μm (A, two images at right, 3 μm).

Mentions: Mature klp10A-gfp oocytes also showed fluorescent cortical microtubules near the metaphase I–arrested spindle at the oocyte surface. Optical sections through the cortex of fixed whole-mount oocytes frequently showed microtubules attached to a pole body (Fig. 2 A, arrows). KLP10A binding to both the pole bodies and cortical microtubules implies a potential role in anchoring the meiosis I spindle to the cortex and positioning the spindle in the oocyte.


A microtubule-destabilizing kinesin motor regulates spindle length and anchoring in oocytes.

Zou J, Hallen MA, Yankel CD, Endow SA - J. Cell Biol. (2008)

KLP10A binds to both spindle poles and cortical microtubules. (A) Meiosis I spindles in fixed klp10A-gfp oocytes show pole bodies attached to cortical microtubules (arrows). (B) Fixed gfp–α-tubulin or klp10A-gfp oocytes treated with microtubule-destabilizing/stabilizing drugs show changes in GFP–α-tubulin (top) or KLP10A-GFP cortical microtubule signals (middle) and spindle length (bottom). Taxol causes increased KLP10A-GFP spindle fluorescence (arrows). Bars, 5 μm (A, two images at right, 3 μm).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2234233&req=5

fig2: KLP10A binds to both spindle poles and cortical microtubules. (A) Meiosis I spindles in fixed klp10A-gfp oocytes show pole bodies attached to cortical microtubules (arrows). (B) Fixed gfp–α-tubulin or klp10A-gfp oocytes treated with microtubule-destabilizing/stabilizing drugs show changes in GFP–α-tubulin (top) or KLP10A-GFP cortical microtubule signals (middle) and spindle length (bottom). Taxol causes increased KLP10A-GFP spindle fluorescence (arrows). Bars, 5 μm (A, two images at right, 3 μm).
Mentions: Mature klp10A-gfp oocytes also showed fluorescent cortical microtubules near the metaphase I–arrested spindle at the oocyte surface. Optical sections through the cortex of fixed whole-mount oocytes frequently showed microtubules attached to a pole body (Fig. 2 A, arrows). KLP10A binding to both the pole bodies and cortical microtubules implies a potential role in anchoring the meiosis I spindle to the cortex and positioning the spindle in the oocyte.

Bottom Line: We frequently observe the pole bodies attached to cortical microtubules, indicating that KLP10A could mediate spindle anchoring to the cortex via cortical microtubules.A dominant-negative klp10A mutant shows both reoriented and shorter oocyte spindles, implying that, unexpectedly, KLP10A may stabilize rather than destabilize microtubules, regulating spindle length and positioning the oocyte spindle.By altering microtubule dynamics, KLP10A could promote spindle reorientation upon oocyte activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.

ABSTRACT
The kinesin-13 motor, KLP10A, destabilizes microtubules at their minus ends in mitosis and binds to polymerizing plus ends in interphase, regulating spindle and microtubule dynamics. Little is known about kinesin-13 motors in meiosis. In this study, we report that KLP10A localizes to the unusual pole bodies of anastral Drosophila melanogaster oocyte meiosis I spindles as well as spindle fibers, centromeres, and cortical microtubules. We frequently observe the pole bodies attached to cortical microtubules, indicating that KLP10A could mediate spindle anchoring to the cortex via cortical microtubules. Oocytes treated with drugs that suppress microtubule dynamics exhibit spindles that are reoriented more vertically to the cortex than untreated controls. A dominant-negative klp10A mutant shows both reoriented and shorter oocyte spindles, implying that, unexpectedly, KLP10A may stabilize rather than destabilize microtubules, regulating spindle length and positioning the oocyte spindle. By altering microtubule dynamics, KLP10A could promote spindle reorientation upon oocyte activation.

Show MeSH