Fig. 3. Dx activates N signaling in a Su(H)-independent manner. (A) A mid-third-instar wing disc of vgBE-lacZ. ß-GAL protein is shown in green. (B,C) Overexpression of Dx (purple) along the AP boundary in a mid-third-instar wing disc ectopically activated the vgBE (green) in both dorsal and ventral compartments of the wing pouch. B and C show a single green channel and a merged image, respectively. (D) In the wing disc dissected from a vgBE Su(H)m-lacZ transgenic line, ß-GAL (green) was not detected along the DV boundary. (E,F) Overexpression of Dx (purple) along the AP boundary did not activate vgBE Su(H)m-lacZ (green). E and F show a single green channel and a merged image, respectively. (G-J) Within Su(H)⁴⁷/Su(H)⁴⁷ mutant clones (marked by an absence of green fluorescence) generated in the late-third-instar wing disc, an overexpression of N^ICD (blue) failed to activate the vgBE along the AP boundary (purple). J is a merged image of G, H and I. (K-N) Within Su(H)⁴⁷/Su(H)⁴⁷ mutant clones (marked by an absence of green fluorescence) generated in the late-third-instar wing disc, an overexpression of Dx (blue) still activated the vgBE (purple). N is a merged image of K, L and M. (O) Overexpression of Dx (purple) along the AP boundary induced ectopic expression of Wg mostly, but not exclusively, in the ventral region of the wing pouch (green). (P) Misexpression of double-strand RNA of N along the AP boundary resulted in the suppression of Wg expression (green) in the late-third-instar wing disc. (Q,R) Overexpression of Dx (purple) with double-strand RNA of N failed to induce the ectopic expression of Wg (green) in the late-third-instar wing disc. Q and R show a single green channel and a merged image, respectively. (S-V) Expression of the wg gene (blue) detected by in situ hybridization in the late-third-instar disc. (S) wg expression in the wild-type wing disc. (T) Overexpression of Dx along the AP boundary induced a weak ectopic wg expression mostly in the ventral region of the wing pouch. (U) Overexpressed N^FL induced a weak ectopic wg expression. (V) Co-expression of Dx and N^FL resulted in a synergistic enhancement of N signaling revealed by strong wg expression along the AP boundary. (W-Z) Within Dl^REV10 and Ser^RX106 double mutant clones (marked by an absence of green fluorescence) generated in the late-third-instar wing disc, an overexpression of Dx (blue) still activated the vgBE (purple). Z is a merged image of W, X and Y. UAS-dx (B,C,E,F,O-R,T-V,W-Z) and UAS-N^IR (P-R) were driven by ptc-GAL4. UAS-dx (K-N) and UAS-N^ICD (G-J) were driven by dpp-GAL4.