Transgenic construct used in an enhancer blocking assay to study the properties of the '1A-2' su(Hw) binding region. A 79bp fragment of the 1A-2 region, containing two su(Hw) protein binding sites, has been inserted into the Yp2-lacZ reporter of P{Yp2-lacZ.FBE1.ctrl}, in between the FBE1 enhancer and the Yp2 promoter sequence.