Lack of Omb causes cells to retract toward the basal side. (A) omb null mutant clones (arrowhead), labelled by absence of GFP, contain retracted cells in the clonal center. (B) ombRNAi clones (arrowhead), labelled by absence of Omb, also contain retracted cells in the clonal center. (C-G) x-z scans of omb null mutant clones (marked by absence of GFP) and ombRNAi clones (marked by reduction of Omb). (C) Central (arrowhead) but not the very lateral (arrow) mutant clones contain retracted cells. (D) ombRNAi clone (marked by reduced anti-Omb staining, arrowhead) with strong central retraction toward the basal lamina. (E and F) Reduction of the apical microtubule web in retracting cells of omb null mutant clone (arrowhead, E) and ombRNAi clone (arrowhead, F). (G) The DE-Cadherin level appears normal (arrowhead) in omb null mutant clones (absence of GFP). (H) Dorsal, middle, and ventral views of an omb mutant clone in adult wing.