Four copies of a dimeric Ecol\lexA protein binding site are fused upstream of two Ubx regulatory elements (BX, an embryonic enhancer, followed by 2212H1, a dorsal imaginal enhancer) which are fused upstream of a Ubx promoter driving lacZ expression.
Construct: Four copies of a dimeric Ecol\lexA protein binding site are located more than 7kb upstream of the w+mC promoter.