Fig. 3. tsh induces competence to respond to dpp and wg in peripodial cells. (A-C,F-H,J) PE clones. Anterior is towards the left, and dorsal upwards. (A) Clones expressing an activated tkv receptor (tkvQD+, red) do not activate Eya expression (green) or induce cell-morphological changes (arrows); in addition, Hth expression remains unchanged (blue). (B) Posterior tsh-expressing peripodial clones (Tsh+) induce Eya expression (arrows), but anterior ones do not (arrowheads). (C) In tsh-expressing clones simultaneously mutant for the dpp signal transducer Mad (Tsh+ Mad-; arrows) eya is never induced. (D,E) ME clones (arrows): (D) tkvQD-expressing clone (red) in anterior regions of the disc de-represses Eya (green; the coexpression is seen in yellow). These clones lose Hth expression (blue). (E) Conversely, a Mad– clone (marked by the absence of lacZ, in red) shows a strong reduction of Eya signal. (F) Axin-expressing clones (lacZ, red; arrows) grow normally in the PE, and do not affect Hth expression (green; overlap in yellow). (G) A tsh-expressing PE clone (tsh+; marked with Tsh in red; arrow) shows overgrowth, with more compact nuclei that strongly express Hth (overlap in yellow). (H) Cells in a clone coexpressing Axin and tsh (tsh+ Axin+, marked with Tsh in red; arrow) lose Hth expression and do not overproliferate. (I) An anterior ME Axin-expressing clone (lacZ in red; arrow) lying within the tsh domain (blue) downregulates Hth (green). Hth levels decrease towards the posterior of the clone, as Axin+ cells are farther away from the anterior wg expression domain. In these Axin+ clones, Tsh expression is maintained (co-expression seen in magenta). (J) PE clones expressing simultaneously tsh, Axin and tkvQD (marked with Tsh, red) activate Eya expression both in posterior (arrow) and in anterior (arrowheads) locations.