The R9C11 enhancer is fused upstream of the Drosophila synthetic core promoter (DSCP), followed by a lexA::GAD driver composed of Ecol\lexA fused at the C-terminal end to an extended version of the Scer\GAL4 activation domain (amino acids 148-881) (sequence optimised for Drosophila codon usage). An Hsp70 transcriptional terminator is present.