Crustacean hyperglycemic hormones of Penaeus monodon: Cloning, production of active recombinant hormones and their expression in various shrimp tissues

Abstract

Crustacean hyperglycemic hormone (CHH) is the most abundant peptide in the eyestalk of crustacean. This hormone not only plays its major role in controlling glucose level in the haemolymph, but is also significant to other processes such as ecdysteroid synthesis and ovarian maturation. Multiple forms of CHH have been reported in several species. In addition to the Pem-CHH1 of Penaeus monodon recently identified, here, we report the cloning and characterization of the cDNA encoding another two Pem-CHH peptides, so-called Pem-CHH2 and Pem-CHH3. Both cDNAs contained 381-bp open reading frame encoding 127 amino acids. The cleavage at the putative processing site of the signal peptide, KR, would generate a 74 amino acids mature hormone for both Pem-CHH2 and Pem-CHH3. Amino acid sequence analysis revealed that Pem-CHH2 and Pem-CHH3 shared 95% identity in their amino acid sequences to that of Pem-CHH1. Both recombinant Pem-CHH2 and recombinant Pem-CHH3 expressed as secreted proteins in Pichia pastoris exhibited hyperglycemic activity at the comparable level to that of Pem-CHH1. Furthermore, investigation of the transcripts of each Pem-CHH in several tissues by RT-PCR showed that expression of Pem-CHH1, Pem-CHH2 and Pem-CHH3 was not restricted only to the eyestalk but also detectable in the heart. In addition, the transcript of Pem-CHH1 was also present in the gill. CHHs from various origins may play different roles and thus contribute towards its pleiotropic nature. © 2003 Elsevier B.V. All rights reserved.