Isolation of growth hormone gene from the Malaysian mahseer, Tor tambroides

Abstract

A study was done to clone a cDNA of the Malaysian mahseer (Tor tambroides) growth hormone (GH) gene. In this study, an RT-PCR technique was used to isolate the GH gene using RNA extracted from brain tissue of T. tambroides. The fragment obtained was purified and cloned into pGEM-T easy cloning vector. The GH cDNA of T. tambroides consists of 1,189 nucleotides (nt) excluding the poly (A) tail, with a 36 nt untranslated region (UTR) at the 5’ region and a 520 nt UTR at the 3’ region. The GH cDNA contains an ORF of 633 nt and encodes for a polypeptide of 210 amino acids (aa), including a signal peptide of 22 aa. Comparison of the T. tambroides GH gene with other teleost GH genes indicated that it has the highest similarity with C. carpio GH type 1 (GHI) with which it share 99% and 98% homology in terms of amino acid and nucleotide sequences, respectively. Molecular characterization of the T. tambroides GH gene showed it exhibits typical GH features similar with other teleost GH genes. Therefore, the GH sequence of T. tambroides was successfully isolated and the sequence added to the GenBank database (JF428142). This is the first report of the isolation of a GH gene from this Malaysian indigenous species, and will assist in understanding the molecular characteristics of the T. tambroides GH gene. This could lead to the use of molecular approaches to better understanding the growth of T. tambroides and give an insight into the molecular aspects of its growth performance in aquaculture