MOLECULAR-CLONING OF HEMOCYANIN CDNA FROM PENAEUS-VANNAMEI (CRUSTACEA, DECAPODA) - STRUCTURE, EVOLUTION AND PHYSIOLOGICAL-ASPECTS

Hemocyanin is present as 2 subunits in the hemolymph of Penaeus vannam ei. Isolated from a hepatopancreas cDNA Library of this penaeid shrimp , the cDNA chain (2095 bp) corresponds to a full length hemocyanin mes senger as determined by Northern hybridization, with a short 5' untran slated region (17 bp), an open reading frame (1989 bp counting initiat ion and termination codons) coding for a signal peptide (13 residues) and a mature hemocyanin (648 amino acids), and a 3' untranslated regio n (89 bp) followed by the polyadenylated track, It is the first time t hat the existence of a hydrophobic signal peptide is shown in arthropo d hemocyanin. Two primary N-terminal sequences are determined and a 3- fold increase of mRNA content, measured in the hepatopancreas during t he premoult stages, is reported, The low level of polymorphism shown b y P. vannamei hemocyanin, along with its weak percentage identity with counterparts and its similarity with hemocyanin from Panulirus interr uptus, suggests that this arthropod hemocyanin may be a primitive subu nit that has evolved independently, following gene duplication. (C) 19 97 Federation of European Biochemical Societies.