IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Growth hormone receptors in zebrafish (Danio rerio): adult and embryonic expression patterns
Autor/es:
DI PRINZIO, C.; ARRANZ, S.E.
Lugar:
Buenos Aires, Argentina
Reunión:
Congreso; 4th International Meeting of the Latin American Society of Developmental Biology (LASDB); 2008
Institución organizadora:
Latin American Society of Developmental Biology (LASDB)
Resumen:
Growth hormone (GH) and somatolactin (SL) are evolutionary related hormones, being SL an exclusive fish hormone. Though both hormones have been related to numerous physiological processes, little is known about their mechanism of action and physiological roles. In several fish species two types of receptors for GH (GHRI and GHRII) and one type for SL (SLR) have been characterized, being the last one, homologue to GHR type I. We identify two configs of the zebrafish genome, containing putative GHRs sequences; one of them located in the chromosome 8 and the other in the chromosome 21. We cloned the full-length cDNA sequence of both receptors, as deduced from a phylogenetic study, using known fish GHR proteins. Ghra (homolog to GHR type I) and ghrb (homolog to GHR type II) gene organization was deduced. The protein sequence of ghra has 41% of identity with ghrb. We studied the tissue specific expression patterns of both receptors in adult zebrafish tissues and during zebrafish development using RT-PCR-Southern techniques. The data showed that both genes are expressed during early development and in adult tissues, and that there exist alternative transcripts for both receptors. We identified alternative fragments for both types of receptors in all tissues studied. This is the first time that this kind of pattern is observed in fishes GHRs, being the cause of this, probably the fact that the alternative forms are expressed in lower levels than the complete form and only could be detected with hybridization techniques. Tissue expression patterns of ghra and ghrb are in agree with studies made in another fish species, with some little differences, as in the case of brain, in which receptors expression has been detected in all species studied to date except zebrafish. Developmental patterns indicate that ghrs are expressed from 24 hpf, being undetectable in earlier stages, indicating a zygotic origin. In the case of ghra, only the short transcript was detected at 24 hpf, while both transcripts were found at 48 hpf, 72 hpf and 5 dpf. In the case of ghrb, both types of transcripts were observed from day 1 to 5. The ghrs alternative transcripts found in the present work, could modulate tissue response to growth hormone both in early embryos and adult animals.