Fig. 5. Wg, Hh and Egfr signalling are required for maintenance of Cut and Sal expression in the posterior spiracle. (A) Schematic representation of the delayed effects of DN molecules expression on Sal and Cut expression, and correspondence between embryonic stages and times of development at 25°C. (B-E) Sal expression in sal-Gal4/UAS-DN-TCF (C) and Cut expression in ems-Gal4/UAS-DN-TCF (E) in late stage 12 embryos are not affected compared with expression in wild-type embryos (B,D). (F-I) Anti-Sal staining at stage 13. Wild-type embryos (F), and embryos carrying sal-Gal4 and UAS-DN-TCF (G), UAS-DN-Egfr (H) or UAS-DN-Ci (I). Black brackets indicate cells close to the spiracular opening and white brackets indicate more distant cells, in which Sal is no longer detected upon signalling inhibition. (J-M) Anti-Cut staining at stage 13. Wild-type embryos (J), or embryos carrying ems-Gal4 and UAS-DN-TCF (K), UAS-DN-Egfr (L) or UAS-DN-Ci (M). The discontinuous lines encircle spiracular chamber cells, where Cut expression is significantly reduced upon signalling inhibition.