In vivo regulation of tissue-specific and LPS-inducible expression of the Drosophila Cecropin genes.

The inducible production of antibacterial cecropins in Drosophila fat body and haemocytes is controlled at the level of transcriptional induction. We demonstrate using germ-line transformation that a short, highly conserved, DNA region, including the insect kappaB motif, is necessary for tissue-specific expression in larvae and adults. Quantitative measurements of reporter gene activity in extracts from transgenic larvae confirmed the requirement of this proximal region for LPS-inducible expression in vivo. Transient expression in a blood cell line indicates the existence of positively acting elements further upstream of the conserved region. Furthermore, our in vivo data suggests that the distal upstream region contains negatively acting element(s).