title: Insulin-like growth factor-binding protein (IGFBP)-1, -2, -3, -4, -5, and -6 and IGFBP-related protein 1 during rainbow trout postvitellogenesis and oocyte maturation: molecular characterization, expression profiles, and hormonal regulation.
abstract: In the present study we report the full coding sequence of rainbow trout IGF-binding protein-1 (IGFBP1), -2, -3, -5, and -6 and IGFBP-related protein-1 (IGFBP-rP1) mRNAs as well as the partial coding sequence of IGFBP-4 mRNA. To our knowledge, this is the first report of IGFBP4, IGFBP6, and IGFBP-rP1 in a nonmammalian species. The tissue distribution of all mRNAs was studied, and the ovarian expression profiles of IGFBP2 to -6 and IGFBP-rP1 between late vitellogenesis and oocyte maturation were characterized. In addition, in vitro hormonal regulation by the maturation-inducing steroid 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP), gonadotropin, and estradiol were studied. We observed that besides IGFBP1, which was only found in liver, IGFBP2 to -6 and IGFPB-rP1 were expressed in the preovulatory ovary. IGFBP3 was also detected in liver, trunk, kidney, skin, and gills, whereas IGFBP2 to -6 and IGFBP-rP1 exhibited a wider tissue distribution. In the preovulatory ovary, IGFBP3 was strongly down-regulated during the postvitellogenesis period, whereas IGFBP5 exhibited a limited up-regulation. In addition, IGFBP6 and IGFBP-rP1 were up-regulated during oocyte maturation. Hormonal regulation data indicated that all ovarian IGFBPs and IGFBP-rP1 transcripts are regulated under gonadotropic stimulation at a concentration that induced 100% oocyte maturation. In addition, IGFBP2 to -5 transcripts are regulated by 17,20betaP and estradiol. Together, our observations strongly suggest that during final oocyte maturation, a down-regulation of IGFBP3, -4, and -5 occurs in the oocyte in response to gonadotropic and 17,20betaP (IGFBP3 and -5) stimulation, whereas an up-regulation of IGFBP2 and -6 occurs in follicular layers or extrafollicular tissue in response to gonadotropic stimulation.
authors.affiliation: Institute National de la Recherche Agronimique, SCRIBE, Institut Fédératif de Recherche 140, Rennes, France.
authors.forename: Barzan Bahrami
authors.initials: BB
authors.lastname: Kamangar
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Gabillard
authors.forename: Julien
authors.initials: J
authors.lastname: Bobe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D020224:Expressed Sequence Tags; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006728:Hormones / Q000378:metabolism; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000096:biosynthesis*; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000096:biosynthesis*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000096:biosynthesis*; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000096:biosynthesis*; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000096:biosynthesis*; D018976:Insulin-Like Growth Factor Binding Protein 6 / Q000096:biosynthesis*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss; D009865:Oocytes / Q000378:metabolism*; D010053:Ovary / Q000378:metabolism; D010802:Phylogeny; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014818:Vitellogenesis
chemical_list: D018076:DNA, Complementary; D006728:Hormones; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018974:Insulin-Like Growth Factor Binding Protein 4; D018975:Insulin-Like Growth Factor Binding Protein 5; D018976:Insulin-Like Growth Factor Binding Protein 6; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; C102529:insulin-like growth factor binding protein-related protein 1; D004958:Estradiol; D012313:RNA