A sub-fragment of the GMR9D11 enhancer (from the erm locus), in which the klu and dpn/E(spl) binding sites are mutated, is fused upstream of the Drosophila Synthetic Core Promoter (DSCP) promoter followed by a coding sequence consisting of mCherry fused to rLUC (codon optimized for expression in Drosophila), with a nuclear localization signal at the C-terminal end of the open reading frame.