DROSOPHILA IMMUNITY - A SEQUENCE HOMOLOGOUS TO MAMMALIAN INTERFERON CONSENSUS RESPONSE ELEMENT ENHANCES THE ACTIVITY OF THE DIPTERICIN PROMOTER

Bacterial challenge of larvae or adults of Drosophila induces the rapi d transcription of several genes encoding antibacterial peptides with a large spectrum of activity One of these peptides, the 82-residue ant i-gram negative diptericin, is encoded by a single intronless gene and we are investigating the control of expression of this gene. Previous studies using both transgenic experiments and footprint analysis have highlighted the role in the induction of this gene of a 30 nucleotide region which contains three partially overlapping motifs with sequenc e homology to mammalian NF-kappa B and NF-IL6 response elements and to the GAAANN sequence present in the interferon consensus response elem ents of some mammalian interferon-induced genes. We now show that the latter sequence binds in immune responsive tissues (fat body, blood ce lls) of Drosophila a similar to 45 kDa polypeptide which cross-reacts with a polyserum directed against mammalian Interferon Regulatory Fact or-1, Using a transfection assay of Drosophila tumorous blood cells, w e show that the GAAANN sequence positively regulates the activity of t he diptericin promoter, We propose that this motif cooperatively inter acts with the other response elements in the regulation of the dipteri cin gene expression.