L Journal of Experimental Marine Biology and Ecology 244 (2000) 145–156 www.elsevier.nl / locate / jembe Molecular cloning of a cDNA encoding a member of CHH / MIH / GIH family from Penaeus monodon and analysis of its gene structure * Apinunt Udomkit , Sunthorn Chooluck, Burachai Sonthayanon, Sakol Panyim Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand Received 10 July 1999; accepted 28 August 1999 Abstract 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 59 and 39 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.  2000 Elsevier Science B.V. All rights reserved. Keywords: Eyestalk; Neuropeptide; Penaeid shrimp; Rapid amplification of cDNA ends 1. Introduction A number of physiological processes in decapod crustaceans are known to be regulated by diverse neuropeptides synthesized by a neurosecretory system called *Corresponding author. Tel.: 1 66-24-419-003 ext: 1237; fax: 1 66-24-419-906. E-mail address: staud@mahidol.ac.th (A. Udomkit) 0022-0981 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0022-0981(99)00134-3