Fig. 1. Wg signalling does not delimit the notal Iro-C domain. (A-C) Domains of Iro-C expression in second, early third and late third instar wg^CX3/wg^CX4 wing discs, respectively. Arrows indicate ectopic nota; arrowhead, residual hinge territory. (D,E) Early third instar disc with clones of cells overexpressing UAS-Axin (red). The clones did not affect the distal border of Iro-C expression (arrowhead in green channel image, E). (F) Early third instar disc expressing UAS-dTCF driven by dpp^disk-Gal4. The distal border of Iro-C expression (green) was not appreciably disturbed. Arrow points to region of maximal UAS-dTCF expression. Red channel, Wg counterstaining. (G) An older disc similarly expressing UAS-dTCF showed abnormal pattern of Wg (red, compare with Fig. 2G) in the wing pouch, indicating the activity of the construct. Control flies expressing this or the UAS-Axin construct showed typical wg insufficiency phenotypes. (H) Second instar wild-type disc stained for Tsh (red) and Iro-C (yellow or green; green channel shown at right). Note the absence of Tsh protein from the prospective wing pouch (arrowhead). (I) Older late second instar wg^CX3/wg^CX4 wing disc, stained as in H. Tsh is almost not removed from the distal part of the disc (asterisk), indicating the failure of the residual Wg to specify the wing territory (Wu and Cohen, 2002). Compare also with Fig. 4I.