Fig. 1. Notch modulates the activity of an activated form of Armadillo. (A-D) Apical sections through third larval instar wing discs stained for endogenous Armadillo (N27A1) and expressing different signalling molecules under the control of dpp GAL4. (A) Wild-type wing disc. Notice elevated levels of Armadillo around the dorsal-ventral boundary (arrow) which coincide with high levels of Wingless signalling. The white line indicates the region of ectopic expression in experimental situations. (B) Disc expressing TNotch. Slight differences in the pattern of endogenous Armadillo, particularly at the DV boundary are observed. (C) Wing disc expressing Armadillo^s10 (Pai et al., 1997). This molecule lacks the epitope recognised by the monoclonal antibody N27A1. The domain of expression of Armadillo^S10 expression is demarcated by changes in the concentration and subcellular location of the endogenous Armadillo. Also note the alterations of growth in the notum (arrowhead) (see Pai et al., 1997). (D) Co-expression of TNotch with Armadillo^S10 suppresses significantly the effects of Armadillo^S10 both on the shape of the disc and on the altered distribution of endogenous Armadillo (compare to C, similar focal plane, also see Fig. S1 in supplementary material). (E-G) Wing disc expressing Armadillo^S10, apical section at the level of the adherens junctions; posterior to right and anterior to left. (E) Armadillo^S10 detected with anti-myc antibody. Notice its association with the adherens junctions. (F) Endogenous Armadillo (N27A1 antibody) is excluded from the adherens junctions over the domain of Armadillo^S10 expression. The shadows correspond to the cells from the peripodial membrane. (G) Merged image of E and F.