Isolation and characterization of the growth hormone receptor in Pejerrey (Odontesthes bonariensis)

BOTTA, PABLO; SCIARA, ANDRÉS A; ARRANZ, SILVIA E.

Mar del Plata, Argentina

Congreso; XLIII Reunión anual de la Sociedad Argentina de Investigacion en Bioquímica y de Bilogía Molecular; 2007

Sociedad Argentina de Investigacion en Bioquímica y de Bilogía Molecular

Growth hormone (GH) is a pluripotent regulator that is involved in metabolism and linear growth of fish. It exerts its functions interacting with a GH receptor (GHR) on the cell membrane of the target tissues. GHR belongs to the hematopoietic cytokine receptor superfamily, it has a single extracellular domain with conserved cysteine residues (Cys) that are involved in the GH binding, one transmembrane domain, and one intracellular domain with conserved regions and conserved tyrosine residues (Tyr). There are two types of GHRs in fish (GHRI and GHRII) that differ in the number of Cys and Tyr between each other. It has been proved that the effect of GH in growth is closely related with the GHR transcription level in liver. Our group is interested in the endocrinology of growth in Pejerrey (Atheriniformes). We are characterizing the GH receptor in this species. We isolated a 1500 bp cDNA sequence that covers almost the entirely open reading frame of the receptor. It presents a 70% homology with perciformes GHRs, and it has all the features of GHRs type II. We detected transcripts of the receptor in 14 organs. ghrII expression was measured in fish injected with recombinant pjGH using a RT-PCR semiquantitative assay. Although the level of IGF-I mRNA increased significantly 9 h post injection, no variation in the transcription level of GHR was found up to 24 h post injection.