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 pHS1 (a 235bp genomic fragment whose distal end corresponds to the proximal breakpoint of the 594 bp deletion in Abd-B^iab6,7-P18.1) has been inserted upstream of the ftz enhancer sequences.