Cloning and expression of melanin-concentrating hormone 1 gene in Florida red tilapia (Oreochromis sp.)

We cloned the cDNA sequence of prepro-melanin-concentrating hormone 1 (pmch1) gene in Florida red tilapia (Oreochromis sp.), referred as flpmch1, to analyze the variation in tissue expression for Florida red tilapia with genetic black spots and those after cold stress by real-time quantitative PCR (qRT-PCR). The bioinformatics analysis reveals that the full length of flpmch1 gene was 629 bp, including an open reading frame of 411 bp encoding putative protein of 136 amino acids. It is predicted that the flpmch1 contained 12 potential phosphorylated sites and a CpG island with length of 199 bp. Compared with Pmch1 amino acid structures of 24 species, Flpmch1 was structurally similar with Pmch1 of O.niloticus, O.aureus, O.mossambicus and Neolamprologus brichardi. The phylogenetic tree analysis shows that Flpmch1 and other teleost formed a Clade, and Flpmch1 had the highest identity to O.niloticus Pmch1. In terms of tissue distribution in Florida red tilapia with genetic black spots, flpmch1 mRNA was widely expressed in various tissues with the highest expression level in brain, and the expression level in pinky white skin was significantly higher than that in black skin. The flpmch1 mRNA expression in tissues decreased after cold stress. The results indicate that flpmch1 is involved in the formation of genetic black spots and skin melanin pigmentation for Florida red tilapia after cold stress.