Transgenic construct used to study sequence identified as a putative Polycomb Group response element (PRE). Derived from P{(FRT)Ubx-lacZ.BH}; a fragment from the Psc-Su(z)2 genomic region (fragment PP4.2, coordinates 2R:8865694..8869872 of the release 5 genome sequence) has been inserted into the FRT cassette, upstream of the Ubx-lacZ reporter.