Transgenic construct used to study sequence predicted to be a candidate Polycomb/Trithorax response element (PRE/TRE). Derived from P{UAS-lacZ.U/l5}, which contains the Ecol\lacZC4.UAS reporter and a w+mC marker; the candidate sequence, a 3kb fragment from 2kb downstream of prod (genomic coordinates 14,029,608-14,032,676), has been inserted upstream of the w+mC marker and its effects on w expression have been analyzed.