Fig. 4. Dx modulates the intracellular distribution of N. (A-L) Confocal microscopic images of third-instar wing discs overexpressing Dx. The boundaries of the region overexpressing Dx are shown by white lines. (A,C,E,G) Overexpression of Dx (blue in E and G) resulted in the depletion of N (green in A and G), but not Dl (purple in C and G), from the apical cell surface. G is a merged image of A, C and E. (B,D,F,H) In the basal plane, overexpression of Dx (blue in F and H) increased N (green in B and H) in intracellular vesicles. In the cells overexpressing Dx, Dx, but not Dl, was frequently co-localized with N in these vesicles (the left part of B-H). In contrast, N co-localized with Dl in the wild-type cells (the right part of B-H). Similar results were obtained when N was stained either with antibodies against the intracellular domain or against the extracellular domain of N. H is a merged image of B, D and F. (I-L) An optical cross-section of a wing disc overexpressing Dx, stained as in A-H. N (green) and Dl (purple) staining are shown in I and J, respectively. K is a merged image of I and J. L shows Dx (blue) staining merged with K. (M-P) A third-instar wing disc overexpressing Dx (blue) was incubated with fluorescein Dextran (green) to label the endocytic compartments. Fluorescein Dextran (green) and endogenous N (purple) were co-stained. Some of the vesicles containing Fluorescein Dextran and N, although not all, were also marked with Dx (shown by white arrowheads). P is a merged image of M, N and O. UAS-dx was driven by ptc-GAL4.