Fig. 2. (A-D) Localisation of Sdt and Drosophila PATJ in sdt^K85 mutant pupal photoreceptor cells upon expression of different Sdt transgenes. Optical cross sections of pupal eyes at 40-45% p.d., before formation of the stalk membrane. MARCM clones mutant for sdt^K85 (A) and those mutant for sdt^K85 and expressing different Sdt-encoding transgenes (B-D) were stained with anti-Sdt-PDZ (A,C), anti-SdtN (B), or anti-PATJ (D) (red), and anti-E-cadherin (A,C,D) or anti-Arm (B) to stain the zonula adherens (blue). Mutant cells expressing a transgene are marked by GFP (green). Depending on the optical section level, the green staining is sometimes weaker. Cells not expressing GFP are wild type and serve as a control to demonstrate that Sdt and PATJ localise apically in PRCs at this stage.