title: Molecular characterization and transcriptional regulation by GH and GnRH of insulin-like growth factors I and II in white seabream (Diplodus sargus).
abstract: Insulin-like growth factors (IGF) I and II are key regulators of development, growth and reproduction in fish. In the present study we have cloned and characterized the cDNA and genomic sequences of IGF-I and IGF-II in the white seabream (Diplodus sargus). The igf1 and igf2 genes were encoded putatively by five and four exons, respectively. Moreover, the 5'-flanking upstream region of the igf1 gene contained highly conserved regulatory elements including HNF-1α, HNF-3β, CCAAT/enhancer binding protein (C/EBP) and the TATA box. The full-length cDNAs were 1225 and 1666 nucleotides long for igf1 and igf2, respectively. Sequence analysis identified the A-E domains as well as three spliced forms involving the E domain in exons 3-5. ORF identities were higher than 83% with respect to other fish orthologs. Expression analysis demonstrated that igf1 and its spliced forms were mostly expressed in liver, whereas the igf2 was expressed ubiquitously not detecting significant differences among the ten tissues analyzed. Hormonal treatments using the porcine GH demonstrated a sharply increase of both igf1 and igf2 mRNA levels in liver and gills at 30 min and 1h after injection. In the gonads, igf1 mRNA levels increased steadily with testis and ovary maturation. In contrast, igf2 transcript amounts were higher in immature stages (S1-S2). Hormonal treatments using GH and GnRH demonstrated that igf1 and igf2 expression were upregulated in the gonads. Overall, these data demonstrate that IGF-I and IGF-II are locally expressed in several tissues and regulated by key hormones of the somatotropic and gonadotropic axes.
authors.affiliation: IFAPA Centro El Toruño, Junta de Andalucía, Camino Tiro Pichón s/n, 11500 El Puerto de Santa María, Cádiz, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Pérez
authors.affiliation: Institute of Marine Science of Andalusia (ICMAN). CSIC, Av Republica Saharaui, 2, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Juan Bosco
authors.initials: JB
authors.lastname: Ortiz-Delgado
authors.affiliation: IFAPA Centro El Toruño, Junta de Andalucía, Camino Tiro Pichón s/n, 11500 El Puerto de Santa María, Cádiz, Spain. Electronic address: manuel.manchado@juntadeandalucia.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Manchado
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D005880:Gills / Q000254:growth & development / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics*; D013006:Growth Hormone / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis / Q000235:genetics*; D008099:Liver / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D021541:Sea Bream / Q000235:genetics / Q000254:growth & development
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone
keywords: Diplodus sargus; Gene expression; Growth hormone; IGF-I; IGF-II; Insulin-like growth factors