Molecular cloning of a cDNA encoding a member of CHH/MIH/GIH family from Penaeus monodon and analysis of its gene structure

We report the nucleotide and deduced amino acid sequences of Pem-CMG peptide, a member of crustacean CHH/MIH/GIH peptide family, in black tiger prawn (Penaeus monodon). The 5' and 3' fragments of Pem-CMG cDNA were cloned by the method of rapid amplification of cDNA ends (RACE). The two fragments constitute a combined cDNA length of 593 bp with a 77 bp overlapping region. Sequence analysis reveals the presence of a 384 bp open reading frame which was subsequently cloned. The open reading frame encodes a precursor peptide that is comprised of 128 amino acids, with a putative processing site, KR. The mature peptide consists of 74 amino acid residues, the sequence of which is significantly homologous to those of the CHH/MIH/GIH family known from other crustaceans. Analysis of a genomic fragment of Pem-CMG reveals a single intron of 314 bp interrupting the coding sequence for the mature peptide. The presence of only one intron in Pem-CMG gene suggests that this gene is structurally different from the previously reported MIH gene of Charybdis feriatus and CHH-like gene of Metapenaeus ensis which possess two introns in their coding sequences.