Ubx sequence from -1763 to +1136 of the promoter are fused to lacZ sequences.
2.9kb PstI fragment of Ubx, including 1.7kb 5' flanking sequence and 1.2kb of the first exon is fused in frame to lacZ, creating a gene fusion of the 56th codon of Ubx to the 8th codon of lacZ.
Carried in plasmid "Ubx0", expressed in haploid cell line 1182-4 and the effect of trx and Pc on the Ubx promoter is studied to determine if trx is involved in promoter activation and Pc-dependent repression can be reproduced.