Fig. 7. cmn mutant discs produce reduced levels of active Hh in the P-compartment. Late third instar wing discs were stained with anti-Col (green) or anti-Smo (red) antibody to monitor Hh signaling activity. (A-C). Wild-type wing discs activate col in A-compartment cells near the AP compartment boundary in the wing pouch region (A). disp mutant discs exhibit diminished levels of Col expression in a narrow stripe of A-compartment cells (arrowhead in B). Note that Col staining surrounding the wing pouch region is not controlled by Hh (indicated by asterisks in B). cmn mutant discs fail to express Col at detectable levels near the AP compartment boundary (C). (D-F) Expression of CiU in wild-type (D) or disp (E) discs activates Col expression at comparable levels in P-compartment cells, whereas expression of CiU in cmn mutant discs (F) induces ectopic Col expression in P-compartment cells at levels much lower than wild or disp mutant discs. (G-I). Wild-type (G) and disp (H) discs stabilized Smo at comparable levels in P-compartment cells whereas Smo was only slightly stabilized in P-compartment cells of cmn discs (I).