title: Dynactin-dependent cortical dynein and spherical spindle shape correlate temporally with meiotic spindle rotation in Caenorhabditis elegans.
abstract: Oocyte meiotic spindles orient with one pole juxtaposed to the cortex to facilitate extrusion of chromosomes into polar bodies. In Caenorhabditis elegans, these acentriolar spindles initially orient parallel to the cortex and then rotate to the perpendicular orientation. To understand the mechanism of spindle rotation, we characterized events that correlated temporally with rotation, including shortening of the spindle in the pole-to pole axis, which resulted in a nearly spherical spindle at rotation. By analyzing large spindles of polyploid C. elegans and a related nematode species, we found that spindle rotation initiated at a defined spherical shape rather than at a defined spindle length. In addition, dynein accumulated on the cortex just before rotation, and microtubules grew from the spindle with plus ends outward during rotation. Dynactin depletion prevented accumulation of dynein on the cortex and prevented spindle rotation independently of effects on spindle shape. These results support a cortical pulling model in which spindle shape might facilitate rotation because a sphere can rotate without deforming the adjacent elastic cytoplasm. We also present evidence that activation of spindle rotation is promoted by dephosphorylation of the basic domain of p150 dynactin.
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Marina E
authors.initials: ME
authors.lastname: Crowder
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Flynn
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Karen P
authors.initials: KP
authors.lastname: McNally
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Cortes
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Kari L
authors.initials: KL
authors.lastname: Price
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kuehnert
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Panzica
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Armann
authors.initials: A
authors.lastname: Andaya
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Leary
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616 fjmcnally@ucdavis.edu.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: McNally
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000378:metabolism*; D048430:Cell Shape / Q000502:physiology; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D005260:Female; D008540:Meiosis / Q000502:physiology; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D012399:Rotation; D062211:Spatio-Temporal Analysis; D008941:Spindle Apparatus / Q000378:metabolism*; D013223:Statistics as Topic
chemical_list: D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D004398:Dyneins