Transgenic construct used in enhancer blocking and anti-silencing assays. The construct contains elements in the following order: the y body cuticle enhancer, an FRT cassette containing the 661bp Polycomb Response Element (PRE) from the regulatory region of Ubx, the y wing blade enhancer, a loxP cassette containing a 340-bp 'MCP' insulator that includes a pita binding site (inserted at -893 relative to the y transcription start site), the y gene (including the intronic bristle enhancer), and a w gene.