Molecular cloning and sequence analysis of growth hormone gene Ⅱof chum salmon (Oncorhynchus keta)

Abstract

A clone which contains the entire growth hormone (GH) gene has been isolated from an EMBL-3 genomic library of Chum salmon (Oncorhynchus keta ) which was constructed in our laboratories. The entire nucleotide sequence was determined, and the gene consists of six exons and five introns spanning 3361 base-pairs(bp) in length. The sequence predicts a polypeptide of 210 amino acids including a putative signal peptide of 22 hydrophobic amino acid residues. The arrangement of exons and introns is identical to that of the other salmonids and tilapia, but different from that for the GH genes of carps which share the similar arrangement of mammals and birds. Comparison of the Chum salmon GH (csGH) genomic gene with the published cDNAs of csGH-I and csGH- Ⅱ reveals that the genomic csGH gene reported in this study belongs to csGH- Ⅱ sharing a 100% homology in coding sequence.