Transgenic construct used to study a Polycomb response element (PRE) in the vg region. Generated in vivo by integration of donor plasmid sequence into the attP site present in the P{attP,y+,w3'} element. As a result of the integration event, a 1kb fragment from the distal vg PRE (normally located ~25kb downstream of vg) is inserted directly upstream of a reconstituted w[+] reporter.