Abstract
Waves of cyclin synthesis and degradation regulate the activity of Cdc2 protein kinase during the cell cycle. Cdc2 inactivation by Wee1B-mediated phosphorylation is necessary for arrest of the oocyte at G2-prophase, but it is unclear whether this regulation functions later during the metaphase-to-anaphase transition. We show that reactivation of a Wee1B pathway triggers the decrease in Cdc2 activity during egg activation. When Wee1B is down-regulated, oocytes fail to form a pronucleus in response to Ca(2+) signals. Calcium-calmodulin-dependent kinase II (CaMKII) activates Wee1B, and CaMKII-driven exit from metaphase II is inhibited by Wee1B down-regulation, demonstrating that exit from metaphase requires not only a proteolytic degradation of cyclin B but also the inhibitory phosphorylation of Cdc2 by Wee1B.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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CDC2 Protein Kinase / antagonists & inhibitors
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CDC2 Protein Kinase / metabolism
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Calcium / metabolism
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Calcium Signaling
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Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cyclin B / genetics
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Cyclin B / metabolism
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Down-Regulation
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Female
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Gene Knockdown Techniques
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Maturation-Promoting Factor / metabolism
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Meiosis*
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Metaphase*
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Mice
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Mice, Inbred C57BL
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Oocytes / physiology*
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Phosphorylation
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
Substances
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Cell Cycle Proteins
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Cyclin B
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RNA, Messenger
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Wee1B protein, mouse
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Protein-Tyrosine Kinases
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Calcium-Calmodulin-Dependent Protein Kinase Type 2
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CDC2 Protein Kinase
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Maturation-Promoting Factor
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Calcium