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.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Anaphase-Promoting Complex-Cyclosome
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Animals
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CDC2 Protein Kinase / antagonists & inhibitors
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CDC2 Protein Kinase / physiology*
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Caenorhabditis elegans / cytology
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Caenorhabditis elegans / genetics*
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Caenorhabditis elegans / ultrastructure
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Caenorhabditis elegans Proteins / antagonists & inhibitors
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Caenorhabditis elegans Proteins / metabolism
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Caenorhabditis elegans Proteins / physiology*
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Cell Cycle Proteins / metabolism
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Cyclin B / physiology
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Cytoplasmic Dyneins / metabolism
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Cytoplasmic Dyneins / physiology
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Dyneins / physiology*
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Embryo, Nonmammalian / cytology
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Embryo, Nonmammalian / drug effects
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Embryo, Nonmammalian / metabolism
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Enzyme Inhibitors / pharmacology
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Meiosis / physiology*
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Microtubules / metabolism
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Purines / pharmacology
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Spindle Apparatus / metabolism*
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Spindle Apparatus / ultrastructure
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Ubiquitin-Protein Ligase Complexes / physiology
Substances
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6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine
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Aspm-1 protein, C elegans
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Caenorhabditis elegans Proteins
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Cell Cycle Proteins
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Cyclin B
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Enzyme Inhibitors
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Purines
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lin-5 protein, C elegans
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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CDC2 Protein Kinase
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Cytoplasmic Dyneins
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DHC-1 protein, C elegans
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Dyneins