Fig. 5. Rab5SN expression alters subcellular localization and mRNA levels of Fz2 and Arrow. (A) In-situ hybridization to Fz2 mRNA in a disc after 4 hours 30 minutes Rab5SN expression in the posterior compartment. Inset shows Rab5SN expression domain (green). (B) In-situ hybridizations detecting arrow mRNA in discs of different genotypes. Left: wild type. Middle: disc expressing GFP-Wg in the posterior compartment for 6 hours. Right: disc expressing Rab5SN in the posterior compartment for 4 hours 30 minutes. (C) Discs expressing Rab5SN in the dorsal compartment for 5 hours 30 minutes stained for Arrow, Fz2 and Armadillo to mark apical junctions. Apical, middle sections and the basal region are shown. Note the accumulation of Fz2 and Arrow above the junctions. Large arrows in middle sections indicate the apical cell surface. In the basal region, the wing pouch curves so that the apical-basal axes of the epithelial cells at the edges of the wing pouch lie parallel to the focal plane. Thus, a complete longitudinal section of these cells is visible. Small arrows point to their basal sides. (D) Larger magnification of the areas boxed in C. Armadillo staining reveals the apical junctions of two rows of epithelial cells facing each other. Fz2 and Arrow accumulate above cellular junctions in Rab5SN-expressing tissue. (E) Single confocal section of a wing imaginal disc expressing YFP-Rab7, CFP-Rab5 and stained for Arrow. Arrowheads indicate co-localization between Arrow and Rab5/7 endosomes. Quantifying ten confocal sections corresponding to the apical-most 10 µm of the disc shown indicates that 49% of the brightest Arrow spots co-localize with either YFP-Rab7 or CFP-Rab5. Scale bar: 20 µm.