Fig. 5. Dpp pathway inhibits Iro-C (green). (A,B) Early third instar wild-type and MS-248 Gal4; UAS-dpp discs, respectively. Iro-C is downregulated in the notum territory (arrowhead). Wing pouch marker: Wg (red). (C,D) UAS-tkv^QD (red, lacZ marker) autonomously inhibits Iro-C in cell clones. Inhibition fails in a region of the lateral-posterior notum (arrowhead in C). Inhibition is also observed in late third instar discs (D, arrowhead). (E,F) Early and late third instar wild-type wing discs. dpp-lacZ expression (red) increases during the third larval instar in the most proximal region of the notum (arrows) and Iro-C is gradually inhibited (M, medial notum; L, lateral notum). (G) tkv^a12 cells (absence of red label) ectopically express Iro-C in the medial notum (asterisk, compare with F). In addition, Iro-C expression is increased within the clone, as compared with the contiguous wild-type territory (arrow). Arrowhead points to the anterior part of the border of the Iro-C domain, which is not modified by the presence of the clone. In contrast, expansion of the Iro-C domain has occurred in the region of the posterior border (red arrow; see also I). (H) Late induced UAS-tkv^QD clones (lacZ marker, red) do not express Iro-C, except at the region within or close to a lateral Dpp source (circled, compare with F). (I) tkv^a12 clone (absence of blue marker) showing a distal expansion of Iro-C expression (arrow), as indicated by the overlap with the Tsh marker (red). Imaginary line between arrowheads would run along the normal border of the Iro-C domain.