Fig. 1. Localisation of Stbm in the developing wing. Confocal images of third instar wing disc (A) or pupal wings (B-K), or images of dorsal surface of adult wings between vein 3 and vein 4 (L-N). Distal is rightwards and anterior is upwards. (A-D) Stbm-YFP is apicolateral and progressively becomes distributed to proximodistal cell boundaries. (E) Staining with an antibody against Stbm shows the protein to be apicolateral and at proximodistal cell boundaries. (F) No Stbm staining (red) is seen in a stbm⁶ mutant clone (labelled by absence of green lacZ staining). Note that Stbm is ectopically localised in cells on edge of clone, owing to the non-autonomous phenotype of stbm clones in the wing (Taylor et al., 1998). (G-I) Stbm-YFP (green) colocalises with Dsh (red, G) and Fmi (red, H) but not Dlg (red, I). (J) Mosaic expression of Stbm-YFP (white in left panel and green in right panel) reveals it to be preferentially localised to proximal cell boundaries (arrowheads), where it is colocalised with the adherens junction marker Armadillo (white in middle panel and red in right panel). Note in this experiment that all cells have endogenous stbm activity and patterning is normal. A subset of cells also express Stbm-YFP. At the boundaries between cells that express Stbm-YFP and those that do not, it is possible to see at which cell boundary Stbm-YFP preferentially localises. (K) Stbm-YFP (green) localises normally in a stbm⁶ mutant clone (labelled by absence of red lacZ staining). (L) stbm⁶/Df(2R)45-30n. (M) stbm⁶/Df(2R)4530n; P[w⁺; Act-Stbm-YFP]/+. (N) stbm⁶ P[w⁺; Act-Stbm- PBM]/stbm^Vang-A3.