Fig. 4. Arrow knockdown causes intracellular Wg accumulation and loss of Wg signaling. (A) Anti-Arrow staining of wing disc with arrow RNAi induced in the dorsal compartment. Dorsal cells lack Arrow, except in four small clones that failed to excise the HcRed cassette and initiate RNAi (imaged using higher gain than Fig. 5C to maximize residual Arrow detection). (B) Top panel shows a control wing. Middle panel shows a wing from a fly that emerged 6 days after arrow RNAi induction in the posterior compartment. Lower panel shows a wing from a fly that emerged 6 days after induction of GFP-Dlp overexpression in the posterior compartment. (C) Projection of 12 confocal sections 1 µm apart from a disc that expressed arrow RNAi in the dorsal compartment for 48 hours, stained for Wg. (D) Single confocal section of the disc shown in (C) showing Wg, CFPRab5 and YFPRab7. Yellow arrowheads show examples of co-localization between Wg and endosomes. Scale bar: 20 µm.