Fig. 2. ds is expressed in the wing disc from early stages. (A-E) Wild-type imaginal wing discs. (A,B) In early- (A) and mid-second (B) instar discs, ds-lacZ expression (red) is confined to the distal part of the wing disc, except in those anterior cells that express Wg (arrowhead). (C) At late second instar, ds-lacZ expression fades away from the P cells adjacent to the AP border (En; green). (D) At early third instar, the ds-lacZ domain forms a ring around the wing pouch that spans the whole hinge territory delimited by Nub (green) and Iro (blue) domains. (E) Spatial distribution of Ds protein is similar to ds-lacZ expression. A cross-section shows that Ds protein is accumulated apically at the plasma membrane. (F) At late third instar, ds-lacZ is expanded into the lateral regions of the notum territory.