Fig. 3. Genetic control of 3'ato³⁴⁸- ßgal expression by RD factors.(A-C) Wild-type L3 eye discs (A) stained for ß-gal (blue) to detect expression of the 3'ato³⁴⁸- ßgal reporter, and for the pan-neural marker Elav (brown) to detect developing neuronal clusters. The 3'ato³⁴⁸- ßgal reporter is not expressed and neurons do not form in so¹ (B) or eya² (C) mutant discs. (D-F) dpp-Gal4-driven expression of Ey (D) or So+Eya (E) in the wing disc activates expression of the 3'ato³⁴⁸-ßgal reporter. A negative control (dpp-gal4 alone) is shown in F; the inset shows the pattern of Gal4 expression in a dpp-Gal4 UAS-lacZ wing disc. (G) dpp-Gal4-driven expression of Ey (D) is not sufficient to induce the 3'ato³⁴⁸- ßgal reporter in the so¹ mutant.