Transgenic construct used in an enhancer-blocking assay. Contains a ftz-lacZ reporter that includes two ftz enhancers (the UPS and NE elements) fused upstream of an Hsp70 promoter followed by the lacZ open reading frame. A fragment consisting of a tetramer of pHS1B (a 133bp genomic fragment whose proximal end is 198bp distal to the proximal breakpoint of the 594 bp deletion in Abd-B^iab6,7-P18.1) has been inserted in between the NE element and the Hsp70 promoter.