Molecular cloning, expression and immunological characterization of pejerrey (Odontesthes bonariensis) growth hormone

SCIARA, A.; RUBIOLO, A.; SOMOZA, G.; ARRANZ, SILVIA EDA

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. TOXICOLOGY & PHARMACOLOGY

Año: 2006 vol. 142 p. 284 - 292

1532-0456

Growth hormone is an essential polypeptide required for normal growth and development of vertebrates. The pejerrey fish, Odontesthesbonariensis, is a South American atherinid freshwater fish considered as a promising species for aquaculture. Although growth hormone has beencharacterized in a number of fish, there are no published data on the structure of this hormone in atherinids, except that of a related speciesOdontesthes argentinensis. In this paper, the molecular cloning, expression and immunological characterization of pejerrey growth hormone(pjGH) is described. The predicted amino acid sequence of pjGH cDNA consisted of 204 amino acid residues with an estimated molecular mass of23 kDa. Amino acid sequence was highly conserved among the two Atheriniformes where the growth hormone sequences are known (99% aaidentity), highly to moderately conserve (75–92% aa identity) when compared to the other members of Acantopterigii superorder and clearly lessconserved (49–66% identity) when compared to Salmoniformes (Protacanthopterygii), Cypriniformes and Siluriformes (Ostariophysi). Aphylogenetic tree depicting the relationship of various teleost GH nucleotide sequences was inferred. Pejerrey GH was produced usingrecombinant DNA technology in a bacterial system, representing the first time an atherinid growth hormone protein was expressed as arecombinant protein in Escherichia coli. A specific antiserum of this hormone was raised in rabbits and its specificity tested by using Western blotand immunocytochemistry. The distribution of pjGH mRNA was also studied by RT-PCR and Southern blot analysis. The transcript was detectednot only in the pituitary gland but also in the testis.