Fig. 4. Relationships of the sal genes with JNK activity and cell death.

(A–A‴) Expression of activated Cas3 (Cas3*; red) in UAS-dicer2/+; sal^EPv-Gal4 UAS-GFP/UAS-salm-i; UAS-salr-i/+ third instar discs. Cell death is observed in the Sal domain, labelled in green, and is particularly prominent in its periphery. The red channels (activated Cas3) are shown in A″ and A‴. (B–B‴) Expression of activated Cas3 in a pupal wing of UAS-dicer2/+; sal^EPv-Gal4 UAS-GFP/UAS-salm-i; UAS-salr-i/+ genotype 36–40 hours APF. (C,C′) Expression of activated Cas3 in en-Gal4 UAS-GFP/UAS-salm-i; UAS-salr-i/+. The expression of activated Cas3 is detected along the anterior–posterior compartment boundary, in the most posterior cells, and in scattered cells located basally in the anterior compartment. (D,D′) Activation of JNK signalling in the posterior compartment of en-Gal4 UAS-GFP/UAS-salm-i; UAS-salr-i/puc-lacZ. The expression of puc-lacZ (blue in D and D′) is detected through the posterior compartment (labelled in green). The expression of Salm is shown in red. (E) sal^EPv-Gal4/UAS-salm-i; UAS-salr-i/+ wing. (F,F′) Third instar wing imaginal disc of sal^EPv-Gal4/UAS-salm-i; UAS-salr-i/puc-lacZ genotype showing the expression of GFP (green in F) and puc-lacZ (single channel in F′). (G,G′) Expression of activated Cas3 (red in G and single channel in G′) in sal^EPv-Gal4/UAS-salm-i; UAS-salr-i/+ third instar discs. The expression of FasIII is shown in green. (H–I′) sal^EPv-Gal4/UAS-salm-i; UAS-salr-i/UAS-puc wing (H) and corresponding imaginal disc showing the expression of activated Cas3 (red in I and single channel in I′) and FasIII (green in I). The expression of activated Cas3 is not prevented by the over-expression of the JNK negative regulator Puc (compare with G′ and I′), but the resulting wing shows an even stronger sal loss-of-function phenotype (compare E with H).