title: CDK-1 inhibits meiotic spindle shortening and dynein-dependent spindle rotation in C. elegans.
abstract: In animals, the female meiotic spindle is positioned at the egg cortex in a perpendicular orientation to facilitate the disposal of half of the chromosomes into a polar body. In Caenorhabditis elegans, the metaphase spindle lies parallel to the cortex, dynein is dispersed on the spindle, and the dynein activators ASPM-1 and LIN-5 are concentrated at spindle poles. Anaphase-promoting complex (APC) activation results in dynein accumulation at spindle poles and dynein-dependent rotation of one spindle pole to the cortex, resulting in perpendicular orientation. To test whether the APC initiates spindle rotation through cyclin B-CDK-1 inactivation, separase activation, or degradation of an unknown dynein inhibitor, CDK-1 was inhibited with purvalanol A in metaphase-I-arrested, APC-depleted embryos. CDK-1 inhibition resulted in the accumulation of dynein at spindle poles and dynein-dependent spindle rotation without chromosome separation. These results suggest that CDK-1 blocks rotation by inhibiting dynein association with microtubules and with LIN-5-ASPM-1 at meiotic spindle poles and that the APC promotes spindle rotation by inhibiting CDK-1.
authors.affiliation: Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Marina L
authors.initials: ML
authors.lastname: Ellefson
authors.forename: Francis J
authors.initials: FJ
authors.lastname: McNally
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D019926:Cyclin B / Q000502:physiology; D056445:Cytoplasmic Dyneins / Q000378:metabolism / Q000502:physiology; D004398:Dyneins / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008540:Meiosis / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D011687:Purines / Q000494:pharmacology; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D043743:Ubiquitin-Protein Ligase Complexes / Q000502:physiology
chemical_list: C471843:6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine; C539484:Aspm-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; D004791:Enzyme Inhibitors; D011687:Purines; C404808:lin-5 protein, C elegans; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D016203:CDC2 Protein Kinase; D056445:Cytoplasmic Dyneins; C502824:DHC-1 protein, C elegans; D004398:Dyneins