PBac{IS.VP16AD.GAL4} represents a transgenic construct generated in vivo using the InSITE system; an enhancer trap cassette that contains a minimal P\T promoter followed by the VP16(AD)::Zip+ hemidriver, derived from the P{ID.VP16AD} donor element, has been inserted into a PBac{IT.GAL4.w-} target element, by first using FLP recombinase to release the donor cassette and then using phiC31:int integrase to insert this cassette into the attP site in the target element. The inserted sequence also includes a loxP cassette (containing the w^+mC marker) and a single FRT site (these are located downstream of the VP16(AD)::Zip+ enhancer trap sequence). The GAL4 enhancer trap cassette present in the original PBac{IT.GAL4.w-} target element has not been excised and a single loxP site is present downstream of this GAL4 enhancer trap cassette.