Fig. 7. Diffusion properties and signaling activity of Hh-GFP, HhN-GFP and Hhc85s-GFP in ttv^- mutant cells. (A-K) ttv^- clones labeled by the absence of b-gal staining (blue) in wing discs expressing Hh-GFP (A-C), HhN-GFP (E-G) and Hhc85s-GFP (I-K) with the hh-Gal4 driver (green) and stained for Ptc (A,E,I), Col (B,F,J) and Iro (C,G,K) in red. HhN-GFP and Hhc85s-GFP, but not wild-type Hh-GFP, appear inside the ttv^- cells and in the cells located anterior to the clone (arrows in E,I). Ptc and Col are expressed only in the first row of ttv^- cells next to the AP border (arrowheads in A,B,E,F,I,J) and Hh-GFP vesicles co-localize with Ptc in all cases (arrowheads in A). Iro is expressed only in the first row of cells in the wild-type Hh-GFP- and Hhc85s-GFP-expressing discs (arrows in C,K). In HhN-GFP-expressing discs, Iro is activated throughout the ttv^- clone (arrowheads in G, clone 1 in H). However, Iro expression decreases in a clone far from the HhN-GFP-producing cells because HhN-GFP levels are lower than at the AP compartment border (arrow in G, clone 2 in H). (D,H,L) Graphs showing the activation of Ptc, Col and Iro in ttv^- clones abutting the AP compartment border (clone 1) or located distant to the AP border (clone 2) by wild-type Hh-GFP (D), HhN-GFP (H) and Hhc85s-GFP (L). The light green represents Hh levels and the graded distribution of the protein produced in the P compartment and secreted to the A compartment; the dark green represents the signaling activity induced by the different Hh forms. The broken lines represent the Hh gradients and signaling activity in a disc that does not contain ttv^- clones.