Fig. 6. Loss of mwh activity results in excess apical actin. Drosophila (A-D') pupal wings immunolabelled for Mwh (green), actin (Ph, magenta or white) and Arm or Fmi (blue), and (E-F'') S2 cells transfected with EGFP-Mwh. (A,A') mwh¹ clone in wing aged 65 hours at 18°C. Arrowheads indicate examples of cells with actin bundles radiating across the entire apical surface, prior to formation of distinct prehair structures. (B,B') mwh¹ clone in wing aged 32.25 hours at 25°C. Prehair formation is more advanced than in the wing shown in A, but some cells still show actin bundles radiating across the entire apical surface (arrowheads). (C,C') mwh¹ clone in wing aged 32.5 hours at 25°C. All mutant cells now showing multiple prehairs forming at the cell periphery. (D,D') Same clone as in C, but sectioned 1 µm deeper, showing excess actin bundles below the apical surface. (E-E'') S2 cell transfected with EGFP-Mwh (green), labelled for actin (Ph, magenta) and plated on Concanavalin A for 1 hour, shows altered morphology with projections extending from cell edges and a loss of actin bundles at cell periphery. (F-F'') DIC image of an S2 cell transfected with EGFP-Mwh (green) and plated on Concanavalin A for 24 hours, showing more extreme phenotype with long filopodia-like extensions around the cell periphery. Scale bars: 10 µm.