Fig. 6. Wg does not appear to induce Emc or H expression in the eye, but emc and/or h is required for Wg-dependent repression of Da expression and bristle formation. (A-D) Wandering third instar eyes; (E-G) pupal eyes (6 h APF) and adult P[sev-wg] eye with emc¹, h^IL clones (H). (A,C) P[dpp-Gal4], P[UAS-lacZ]; (B,D) P[dpp-Gal4], P[UAS-wg]; (E) P[GMR-Gal4], P[UAS-lacZ]; (F) P[GMR-Gal4], P[UAS-wg]; (G,H) clones of emc¹, h^IL in a P[sev-wg] (G) or P[GMR-Gal4], P[UAS-wg] (H) background. (A,B,E,F) H expression; (C,D) Emc expression; (G,H) Da expression. Clonal boundaries were marked with ß-gal (not shown). H is normally expressed in a stripe several cell diameters ahead of the MF (marked with arrows). Emc is expressed in a stripe between the H stripe and MF. In Dpp/wg eyes, Emc is at the posterior edge of the eye (D) and H just anterior. This is consistent with the lack of MF progression in this background. Behind the MF, ectopic expression of wg (via the GMR promoter) does not induce H expression (F) or Emc (data not shown). Removal of emc and h blocks P[sev-wg] from inhibiting Da expression (G) but not P[GMR-Gal4], P[UAS-wg]-dependent Da repression (H). Clonal boundaries are indicated by white lines.