Transgenic construct used to study the gypsy insulator. Contains the w+mC reporter (w promoter and coding region without upstream enhancers). Two copies of the su(Hw) binding region of the gypsy element (nucleotides 647-1077, coordinates according to GenBank:M12927, contains all 12 su(Hw) binding sites) are also present, one upstream and one downstream of w+mC.