Fig. 4. rasp is required for Hh target gene activation. (A-D) Comparison of Hh target gene expression in wing discs heterozygous and homozygous for rasp. (A) ptc-lacZ; rasp9B15/TM6 discs stained with anti-ß-gal (blue) and anti-En (brown). The domain of elevated ptc expression is detectable in a narrow stripe of anterior cells along the AP boundary (arrow). (B) ptc-lacZ; rasp9B15/rasp9B15 discs stained with anti-ß-gal (blue) and anti-En (brown). Levels of ptc-lacZ are reduced in this mutant background (compare A with B). The anti-ß-gal stain was amplified to detect low levels of ptc-lacZ reporter signal (see Materials and Methods). We failed to detect ptc-lacZ expression using fluorescent secondary antibodies. Note the reduced size of the homozygous wing disc. (C) ptc-lacZ; rasp9B15/TM6 discs hybridized to dpp RNA probes (blue). Like ptc-lacZ, dpp is also expressed in a stripe of anterior cells along the AP boundary (arrow). (D) ptc-lacZ; rasp9B15/rasp9B15 discs hybridized to dpp RNA probes (blue). Levels of dpp transcripts are reduced in this mutant background (compare C with D).
