CDNA CLONING AND GENE-EXPRESSION OF LEBOCIN, A NOVEL MEMBER OF ANTIBACTERIAL PEPTIDES FROM THE SILKWORM, BOMBYX-MORI

A cDNA encoding lebocin, a novel member of insect antibacterial peptid es, was isolated from the fat body cDNA library of Bombyx mori larvae immunized with Exherichia coli. The cDNA was 844 bp long and had an op en reading frame (ORF) containing a probable signal peptide (16 amino acids), a putative prosegment (104 amino acids) and a mature peptide ( 32 amino acids) followed by 27 additional amino acids at its carboxyl- terminus. Northern blot analysis showed that lebocin gene expression w as inducible by bacterial injection, occured tissue-specifically in th e fat bodies and continued at least for 48 h post-infection. Theses re sults suggest that lebocin has a unique precursor structure and shows typical gene expression pattern as insect abtibacterial peptide. (C) 1 995 Academic Press, Inc.