Figure 5.—

Reducing EGFR signaling phenocopies the differentiation phenotype of loss of Rheb or TOR. pntP2 hypomorphic clones made using the allele pntP2¹²³⁰ show cell-type-specific delays in PR differentiation identical to those seen in LOF clones of positive effectors of InR/TOR signaling such as Rheb and TOR. (A–C) pntP2¹²³⁰ clones have no effect on the differentiation of PR 8 (stained for Senseless expression, shown in red in A and A′), PRs 2/5 (stained for Rough expression, shown in red in B and B′) or PRs 3/4 (stained for Spalt expression, shown in red in C and C′). Note that Spalt staining shows a delay toward the posterior of the disc where the antibody also stains PRs 1 and 6. In contrast pntP2¹²³⁰ clones show a strong delay in the differentiation of PRs 1 and 6 (stained for Bar expression, shown in red in D and D′), PR 7 (stained for Prospero expression, which is also expressed in cone cells, shown in red in E and E′) and cone cells (stained for Cut expression, shown in red in F and F′ and Prospero expression, shown in red in E and E′). LOF clones in all panels are marked by the loss of GFP staining (shown in green). Anterior is to the left in all panels.