Back to Search Start Over

Spherical spindle shape promotes perpendicular cortical orientation by preventing isometric cortical pulling on both spindle poles during C. elegans female meiosis

Authors :
Qianyan Li
Francis J. McNally
Elizabeth Vargas
Daniel B. Cortes
Amy Shaub Maddox
Karen P. McNally
Brennan M Danlasky
Michelle T. Panzica
Source :
Development.
Publication Year :
2019
Publisher :
The Company of Biologists, 2019.

Abstract

Meiotic spindles are positioned perpendicular to the oocyte cortex to facilitate segregation of chromosomes into a large egg and a tiny polar body. In C. elegans, spindles are initially ellipsoid and parallel to the cortex before shortening to a near spherical shape with flattened poles and then rotating to the perpendicular orientation by dynein-driven cortical pulling. The mechanistic connection between spindle shape and rotation has remained elusive. Here we used three different genetic backgrounds to manipulate spindle shape without eliminating dynein-dependent movement or dynein localization. Ellipsoid spindles with flattened or pointed poles became trapped in either a diagonal or a parallel orientation. Mathematical models that recapitulated the shape dependence of rotation indicated that the lower viscous drag experienced by spherical spindles prevented recapture of the cortex by astral microtubules emanating from the pole pivoting away from the cortex. In addition, maximizing contact between pole dynein and cortical dynein stabilizes flattened poles in a perpendicular orientation and spindle rigidity prevents spindle bending that can lock both poles at the cortex. Spindle shape can thus promote perpendicular orientation by three distinct mechanisms.

Details

ISSN :
14779129 and 09501991
Database :
OpenAIRE
Journal :
Development
Accession number :
edsair.doi...........a20478310afcbb1be9b3e5dc9c5e0bae