Expression occurs in a stripe along the center of the wing blade in a region that maps to the site of the L3 vein. Activity reduces gradually both anterior and posterior to this stripe.

Enhancer trap expression isindistinguishable from ds expression in third instar larvae but differssignificantly during embryogenesis. In embryos, enhancer trap expressionis observed in a weak anterior stripe during cellularization and along theventral furrow, cephalic furrow, and in the procephalon duringgastrulation but not in pair-rule stripes. During germ band elongation, noexpression is seen in ectodermal stripes or in tracheal pits. After dorsalclosure, EcollacZ and ds expression are nearly congruent but ectopicexpression is seen in the eighth abdominal segment and no expression isseen in the frontal sac.