Fig. 4. Ectopic Msk affects late eye development. All panels show anterior right, dorsal up; genotypes and temperatures are indicated above panels. (A,D,G,J) GMR:Gal4, raised at 18°C; (B,E,H,K) GMR:Gal4 UAS:Msk, raised at 18°C; (C,F,I,L) GMR:Gal4 UAS:Msk, raised at 25°C. (A-C) Adult compound eyes viewed by light microscopy. Note the reduced red pigment upon the addition of ectopic Msk (compare B and C with A). (D-F) Adult compound eyes viewed by scanning electron microscopy. Note the disrupted facet pattern upon the addition of ectopic Msk (compare E and F with D). (G-I) Adult compound eye sections. Note the reduced numbers of photoreceptor and pigment cells upon the addition of ectopic Msk (compare the area indicated by the arrow in H with G). (J-L) 60-hour pupal eyes, stained for F-actin. Note the disrupted pattern upon the addition of ectopic Msk (compare K and L with J). Note, all phenotypes are accentuated by elevated Msk expression (through increased Gal4 activity) at 25°C (C,F,I,L).