Abstract
Vertebrate oocytes arrest in the second metaphase of meiosis (metaphase II [MII]) by an activity called cytostatic factor (CSF), with aligned chromosomes and stable spindles. Segregation of chromosomes occurs after fertilization. The Mos/.../MAPK (mitogen-activated protein kinases) pathway mediates this MII arrest. Using a two-hybrid screen, we identified a new MAPK partner from a mouse oocyte cDNA library. This protein is unstable during the first meiotic division and accumulates only in MII, where it localizes to the spindle. It is a substrate of the Mos/.../MAPK pathway. The depletion of endogenous RNA coding for this protein by three different means (antisense RNA, double-stranded [ds] RNA, or morpholino oligonucleotides) induces severe spindle defects specific to MII oocytes. Overexpressing the protein from an RNA not targeted by the morpholino rescues spindle destabilization. However, dsRNA has no effect on the first two mitotic divisions. We therefore have discovered a new MAPK substrate involved in maintaining spindle integrity during the CSF arrest of mouse oocytes, called MISS (for MAP kinase-interacting and spindle-stabilizing protein).
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence / genetics
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Animals
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Base Sequence / genetics
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Carrier Proteins / genetics
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Carrier Proteins / isolation & purification*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / isolation & purification*
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Cloning, Molecular
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Embryo, Mammalian / drug effects
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Embryo, Mammalian / embryology
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Embryo, Mammalian / metabolism
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Female
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Genes, myc / genetics
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Intracellular Signaling Peptides and Proteins*
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MAP Kinase Signaling System / physiology*
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Meiosis / physiology*
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Mice
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Mice, Knockout
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Mitosis / genetics
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Molecular Sequence Data
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Mutation / genetics
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Nuclear Proteins / genetics
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Nuclear Proteins / isolation & purification*
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Oligonucleotide Probes / pharmacology
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Oncogene Proteins v-mos / genetics
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Oocytes / cytology
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Oocytes / metabolism*
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Phenotype
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Protein Structure, Tertiary / genetics
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RNA, Messenger / genetics
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RNA, Messenger / isolation & purification
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Spindle Apparatus / metabolism*
Substances
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Carrier Proteins
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Cell Cycle Proteins
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Intracellular Signaling Peptides and Proteins
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MAPK-interacting and spindle-stabilizing protein, mouse
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Nuclear Proteins
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Oligonucleotide Probes
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Oncogene Proteins v-mos
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RNA, Messenger