Transgenic construct used to investigate the possible role of z protein in long-range interactions between enhancers and promoters. Contains an FRT cassette containing the w eye enhancer (-1180 to -1450bp relative to the transcription start site), an FRT cassette containing a 430bp gypsy\su(Hw)BR insulator, a loxP cassette containing a 430bp gypsy\su(Hw)BR insulator, and the w+mC mini-gene.