COMPLETE SEQUENCE, EXPRESSION, AND EVOLUTION OF THE HEXAMERIN LSP-2 OF CALLIPHORA-VICINA

In cyclorraphan Diptera, two different types of hemolymph proteins exi st which belong to the hexamerin family. During the last larval instar , Calliphora vicina synthesizes, besides the major fraction of arylpho rin, a second hexameric protein, LSP-2, Here the developmentally regul ated biosynthesis of this protein was analyzed. Western blot analyses showed that LSP-2 is not present in eggs, 1st, and 2nd instar larvae, whereas it can be detected in all tissues of last instar larvae. We re port the characterization of the complete cDNA sequence that encodes a LSP-2 subunit, a nascent polypeptide of 701 amino acids with a molecu lar mass of 83.16 kDa, By Northern blotting, a mRNA of about 2.2 kb co ding for LSP-2 is identified exclusively in the fat body of 3rd larval instars reflecting the stage and tissue specificity of LSP-2 gene exp ression, Phylogenetic analysis demonstrates the existence of two disti nct groups of hexamerins in Diptera, (C) 1998 Elsevier Science Ltd. Al l rights reserved.