CHAN, S.-M.; GU, P.-L.: The study of shrimp CHH/MIH/GIH gene family: gene structure, expression and biological assay of recombinant neuropeptides

The crustacean CHH/MIH/GIH neuropeptide family constitutes a group of important hormone that regulates important processes such as molting, glucose metabolism and reproduction. The characterization of these neuropeptides has attracted much attention due to their potential importance in aquaculture. By RT-PCR and library screening approach, we have isolated and cloned four cDNAs from the eyestalk of the shrimp Metapenaeus ensis. Two of the cDNAs encoded for proteins are homologous to the CHH-subtypes and two of the cDNA encoded for proteins belong to the MIH/GIH subtypes. The organizations of these genes are very similar. They consist of three exons and two introns with conserved location of boundaries between the intron-exon. There are more than 20 CHH-A genes, 5-6 CHH-B genes and 1-2 copies of MIH and GIH gene in the shrimp genome. CHH-A, CHH-B, MIH- and GIH RNA transcripts can be detected in the eyestalk of animal at most stages. Only CHH-A and GIH transcripts are detected in ventral nerve cord. Recombinant proteins for these neuropeptides have been produced and used for bioassay. Additionally, the recombinant proteins were purified for antibody generation. Specific antibodies against these recombinant proteins were generated and had been used to detect these neuropeptides by immunochemistry. Supported in part by a HKU institutional grant (CRCG) and the RGC of the HKSAR, China (HKU 7229/00M)