Characterization of the zebrafish Orb/CPEB-related RNA binding protein and localization of maternal components in the zebrafish oocyte.
The animal/vegetal axis of the zebrafish egg is established during oogenesis, but the molecular factors responsible for its specification are unknown. As a first step towards the identification of such factors, we present here the first demonstration of asymmetrically distributed maternal mRNAs in the zebrafish oocyte. To date, we have distinguished three classes of mRNAs, characterized by the stage of oocyte maturation at which they concentrate to the future animal pole. We have further characterized one of these mRNAs, zorba, which encodes a homologue of the Drosophila Orb and Xenopus CPEB RNA-binding proteins. Zorba belongs to the group of earliest mRNAs to localize at the animal pole, where it becomes restricted to a tight subcortical crescent at stage III of oogenesis. We show that this localization is independent of microtubules and microfilaments, and that the distribution of Zorba protein parallels that of its mRNA.
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA. bally@gsf.de
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Bally-Cuif
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D008841:Actin Cytoskeleton / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016764:Cell Polarity; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins; D005260:Female; D017403:In Situ Hybridization; D008870:Microtubules / Q000502:physiology; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
D018076:DNA, Complementary; D029721:Drosophila Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029961:Zebrafish Proteins; C116678:cpeb1b protein, zebrafish; C089932:orb protein, Drosophila