A novel lebocin-like gene from eri-silkworm, Samia cynthia ricini, that does not encode the antibacterial peptide lebocin

A cDNA clone with homology to lebocin gene was isolated from fat body of immunized Samia cynthia ricini larvae. The cDNA has an open reading frame encoding 162 amino acid residues. The deduced amino acid sequence shows significant homology to lebocin precursor proteins from Bombyx mori and Trichoplusia ni only in the “prosegment” region, but no homology to mature lebocin, a proline-rich antibacterial peptide, indicating the protein is not a precursor for lebocin antibacterial peptide. Northern analysis indicates that transcript of the lebocin-like gene is not detected in any tissues of naive larvae, but induced mainly in fat body after injection of the larvae with bacterial cells or cell wall components, such as peptidoglycan.