Fig. 1. mop is required for EGFR signaling. (A-F') Third instar Drosophila eye discs. (A,A') mop^T612 mutant clones marked by the absence of GFP (green in A'). Photoreceptors are stained with anti-Elav (A, magenta in A'). (B-B'',C-C'') Eye discs with large mop^T612 mutant clones generated in a Minute background and marked by the absence of GFP (B',C', green in B'',C''). R8 photoreceptors are stained with anti-Ato (B, magenta in B'') or anti-Sens (C, magenta in C''). mop has little effect on R8 differentiation. (D-F') mop^T612 mutant clones marked by the absence of GFP (green in D',E',F'). Activated Caspase 3 staining (D, magenta in D') marks apoptotic cells and Cyclin B staining (E, magenta in E') marks cells in G2 or M phase. Posterior mop mutant clones contain reduced numbers of photoreceptors and show increased cell death and cell cycle re-entry. Phospho-MAPK staining (F, magenta in F') is reduced in mop mutant clones in the morphogenetic furrow (long arrow) and posteriorly (short arrow). (G,H) Embryos stained with anti-β-galactosidase reflecting aos-lacZ expression. (G) Wild type; (H) maternal/zygotic mop mutant. aos expression is strongly reduced in the absence of mop. (I) An adult wing containing mop^T612 mutant clones shows loss of wing vein material (arrow). (J) A third instar wing disc with mop^T612 clones made in a Minute background and marked by the absence of GFP (green), stained with anti-β-galactosidase reflecting aos-lacZ expression (magenta).