Fig. 2. hh^bar3 phenotypes in the developing eye. Eye-antennal imaginal discs, shown anterior rightwards and dorsal upwards. Black arrowheads indicate the morphogenetic furrow. Genotypes are indicated below each panel. (A-F) Hedgehog antigen (red in C and black in the other panels). Boss is in green in C. (G-I) lacZ driven by the BS3.0 dpp enhancer (Blackman et al., 1991). an, antennal disc; oc, ocellar domain. In hh^bar3, Hedgehog antigen is undetectable in the presumptive eye field (compare at white arrows in A and D) but is normal in the ocellar region and in the antennal disc (black arrows in A,D). Hedgehog is first expressed in only two cells per ommatidium (white arrowheads in B) and that these are not Boss-expressing R8 cells (white arrows in C). A low level of anti-Hedgehog stain is seen at the posterior margin near the time of furrow initiation (white arrows in E,F). dpp:lacZ expression is reduced in the furrow in hh^fse and eliminated from the central furrow in hh^bar3. Scale bar in A: 50 µm for A,D,G-I; 10 µm in B; 1 µm in C; in F, 50 µm for E,F.