Figure 2.

Dpp Signaling Counteracts JNK-Dependent Activation of reaper via the Transcriptional Repressor Schnurri

(A and B) p-Smad immunoreactivity, seen in control embryos (A), is not detectable in embryos carrying both UAS-dpp[RNAi] and tubulin-Gal4 (B), confirming the effectiveness of this RNAi transgene. Anti-Engrailed and DAPI were used as morphological landmarks. En, Engrailed; st., stage.

(C) In embryos expressing UAS-dpp[RNAi] under the control of tubulin-Gal4, reaper expression becomes upregulated at the dorsal edge of the epidermis. Such embryos are often misshapen probably because of interference with the patterning activity of Dpp.

(D) Expression of reaper is also upregulated at the dorsal edge of homozygous thickveins (tkv) mutants.

(E) Upregulation of reaper in the dorsal and lateral epidermis of schnurri mutants. Expression can be seen along the whole dorsal edge but is segmental elsewhere. The basis of the segmental pattern is unknown.

(F) Upregulation of reaper throughout most of the epidermis of thickveins crumbs double mutants.

(G) No reaper upregulation is detected in schnurri kayak (fos) double mutants, demonstrating the requirement for canonical JNK signaling in reaper activation.

(H) Expression of reaper is upregulated throughout the epidermis of schnurri crumbs double mutants in a pattern that is roughly the sum of those seen in the single mutants.

Scale bar, 200 μm.