Contains a 2.1kb promoter fragment from the Ubi-p63E gene, including the first nine coding bases. An FRT site is present downstream of the promoter fragment. Recombination between the FRT sites present in each of the PBac{Ubi-p63E.FRT} and PBac{FRT.GFP} constructs reconstitutes a functional "Ubi-GFP" transgene (PBac{Ubi-p63E.FRT.GFP}), with expression of EGFP driven by the Ubi-p63E promoter. This system has been combined with a marker of cell recombination status (P{lacO.256x}60F) to produce a two-part labeling system called "syncytial tracing by recombination-induced transcription" (STRIT).