Trichoplusia ni gloverin, an inducible immune gene encoding an antibacterial insect protein

By using differential display PCR. we obtained a cDNA clone encoding a gloverin homologue from the cabbage looper, Trichoplusia ni. The expression of the gene was induced by bacterial infections. The gene codes for a 174 amino acid residue protein, including a signal sequence and a prosegment. The deduced mature protein is 14 kDa and shows 58% and 49% identity to P2 from Helicoverpa armigera and to Hyalophora gloveri gloverin, respectively. The protein was detected in hemolymph and hemocytes from bacteria-immunized animals, We expressed gloverin using the baculovirus expression system. N-terminal amino acid sequence analysis showed that the purified protein contained a propart. This progloverin inhibited the growth of E. coli and the activity is comparable to that of H. gloveri mature gloverin. Processing of progloverin was possible in vitro. using human furin. (C) 2002 Published by Elsevier Science Ltd.