CDNA SEQUENCE AND EXPRESSION OF THE CERATOTOXIN GENE ENCODING AN ANTIBACTERIAL SEX-SPECIFIC PEPTIDE FROM THE MEDFLY CERATITIS-CAPITATA (DIPTERA)

Ceratotoxins are antibacterial 3-kDa molecular mass amphiphilic peptid es isolated from the female reproductive accessory glands of the medfl y Ceratitis capitata, They are physiologically related to bee melittin and show amino acid sequence homology with magainin peptides,In this paper, we report the complete sequence of cDNA coding for ceratotoxin A and the expression of the gene during the life cycle of the insect, Experimental data show that the ceratotoxin is a gene expressed exclus ively in the imaginal stages and that it is female-specific, related t o sexual maturity, and stimulated by mating, Differently from most ant ibacterial insect hemolymph peptides, it is not induced by microbial i nfection, Western blot analysis using an anti-ceratotoxin antibody ind icates the female accessory glands as the only site where the producti on of the ceratotoxin peptide occurs.