Secretion of antimicrobial peptides (AMP) is a central defense mechanism used by invertebrates to combat infections. In
Drosophila, the synthesis of these peptides is a highly regulated process allowing their rapid release in the hemolymph upon contact with
pathogens and the arrest of their production after pathogen clearance. We observed that AMP genes have either a transient or
sustained expression profile in S2 drosophila cells treated with peptidoglycan. Moreover, AMP genes containing AU-rich elements (ARE) in
their 3' untranslated region (UTR) are subject to a post-transcriptional control affecting mRNA stability, thereby contributing to
their transient expression profile. Cecropin A1 (CecA1) constitutes the prototype of this latter class of AMPs.