CHARACTERIZATION OF A BOMBYX-MORI CDNA-ENCODING A NOVEL MEMBER OF THEATTACIN FAMILY OF INSECT ANTIBACTERIAL PROTEINS

A Bombyx mori cDNA was cloned that hybridized with Hyalophora cecropia attacin probe and its nucleotide sequence was determined. This cDNA c onsisted of 846 nucleotides and the deduced amino acid sequence showed that the cDNA encodes an attacin precursor protein, The putative matu re protein of B, mori attacin had 70.4, 68.3 and 18.8% identity in ami no acid sequences with that of H. cecropia acidic and basic attacins a nd Saucophaga pevegrina sarcotoxin IIA, respectively. B. mori and H. c ecropia attacins and S. peregrina sarcotoxin IIA had two subdomains in each G domain, suggesting that common amino acid residues in the subd omains are conserved during evolution and plays an important role in t he activity of the antibacterial proteins. Expression of B. mori attac in gene was rapidly induced by the injection of Escherichia coli cells into B. mori larvae and continued at least for 48 h mainly in fat bod ies and hemocytes.