Fig. 4. PP2A is essential for Hh signaling. (A,A') A wild-type wing disc was stained to show the expression of Ci^FL and dpp-lacZ. The Ci antibody only recognizes Ci^FL in wing discs. (B,B') A wing disc co-expressing UAS-MtsRNAi with UAS-P35 by MS1096 Gal4 was immunostained with Ci and β-gal antibodies. Arrowhead in B indicates the decreased Ci^FL levels. Arrowhead in B' indicates the downregulated dpp-lacZ expression. MS1096 Gal4 is expressed at lower level in the ventral region than in the dorsal region of the wing disc (Jia et al., 2003). (C-C') A wing disc expressing UAS-WdbRNAi by MS1096 Gal4. Arrowhead in C indicates the decreased Ci^FL and arrowhead in C' indicates the downregulated dpp-lacZ. (D-E') Wing discs expressing UAS-Mts or UAS-Wdb by ap-Gal4. Arrowheads in D and E show the elevation of Ci^FL and arrowheads in D' and E' show the induced ectopic dpp-LacZ expression. (F-F'') A wing disc bearing wdb^IP homozygous clones that were marked by the lack of GFP expression was immunostained with anti-Ci and anti-SmoN antibodies. Arrowhead in F shows the reduction of Ci^FL. Arrowhead in F' shows the unaffected Smo accumulation in wdb mutant cells. (G,H) Wing discs expressing UAS-HA-Ci^FL alone, or along with UAS-Wdb by C765 Gal4. Arrowhead in H indicates the ectopic Ptc-lacZ expression in A-compartment cells.