The shrimp hyperglycemic hormone-like neuropeptide is encoded by multiple copies of genes arranged in a cluster

The crustacean hyperglycemic hormone (CHH) plays an important role in the r egulation of glucose metabolism. We have cloned and sequenced several cDNAs encoding the preproCHH-like of the shrimp, Metapenaeus ensis. The preproCH H-like peptide of the shrimp consists of a signal peptide, a CHH precursor- like peptide (CPRP) and the CHH-like peptide, Comparative analysis revealed that the signal peptide and the CPRP of the shrimp peptide are the shortes t among all the CHHs reported. MeCHH-like is expressed in the eyestalk, but it is not expressed in the heart, hepatopancreas, muscle, nerve cord and p re-hatch embryo. To study the structural organization of the shrimp CHH-lik e gene, we have screened the genomic DNA library constructed from one shrim p. Three groups of overlapping genomic clones have been isolated. The resul ts from both genomic Southern blot analysis and library screening indicate that the shrimp genome contains at least six copies of the CHH-like genes a rranged in a cluster on the chromosome. The size of the CHH-like genes is 1 .5-2.1 kb, DNA sequence determinations indicate that the CHH-like genes sha re 98-100% amino acid sequence identity. There are three exons and two intr ons in each CHH-like gene, The first intron separates the signal peptide an d the second intron separates the mature peptide in the coding region. The 150-200 bp of the upstream 5' flanking region of the CHH-like genes contain s promoters with characteristics similar to most eukaryotic genes. Several putative cis-acting elements are also identified in the first 400 bp 5' end upstream region. The organization of the shrimp CHH-like genes is similar to that of the molt inhibiting hormone gene of the same shrimp and the crab , Charybdis feriatus. (C) 1998 Federation of European Biochemical Societies .