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 PD4.1, coordinates 2R:8842420..8846609 of the release 5 genome sequence) has been inserted into the FRT cassette, upstream of the Ubx-lacZ reporter, in the same orientation as the direction of transcription of the reporter gene.