Transgenic construct used in an analysis of Trithorax response elements (TREs) in the bxd region of Ubx. Contains two divergently transcribed reporters; Ecol\lacZUbx.P140 and a w minigene. Three fragments from the bxd/pbx region upstream of Ubx; an SspI-BamHI fragment (nucleotides 209,575 to 210,192), a HindIII-BglII fragment (nucleotides 214,871 to 221,674) and a BglII-EcoRI fragment (nucleotides 226,706 to 232, 519, all coordinates relative to GenBank accession number U31961) have been inserted in between the two divergent promoters. Nucleotides 218,835 to 219,249 (coordinates relative to GenBank accession number U31961) from the bxd/pbx regulatory sequences have been deleted.