Transgenic construct used in an enhancer-blocking assay. Transgenic construct used to examine the properties of the Mcp element from the bithorax complex. Contains a ftz-lacZ reporter that includes the ftz zebra (Z), neurogenic enhancer (NE) and UPS enhancer elements (the same reporter as in P{ftz-lacZ.ff#1}). A fragment of the gypsy insulator containing 12 su(Hw) protein binding sites has been inserted in between the NE and Z elements.