6kb genomic fragment (from BAC clone CH322-158DO6) that encompasses su(Hw), containing 1.3kb of 5' and 0.5kb of 3' sequence. The zinc-chelating amino acid in zinc finger 3 has been mutated (amino acid replacement H337A).
su(Hw)M3 mutants are female sterile and show partial loss of the gypsy insulator function (assayed through body, wing and bristle phenotypes induced by mutations in the y, ct and f genes) relative to wild-type controls.