Figure 4. Rescue of ciliogenesis with scAAV8 vector expressing cNPHP5, detected with immunohistochemistry using anti-Flag antibody. A–D: Retina cryosections from Nphp5^+/−; Nrl^-/- (A), Nphp5^+/−; Nrl^-/- treated with self-complementary adenoassociated virus 8 (scAAV8)-cNPHP5 (AAV⁺; B), Nphp5^-/-; Nrl^-/- (C), and Nphp5^−/−; Nrl^−/−; AAV⁺ (D) were probed with monoclonal anti-Flag antibody (red). Lower panels show enlargements of hatched boxes. All mice expressed the Egfp-Cetn2⁺ transgene (eCetn2⁺, green) which specifically labels centrioles and transition zones. Please note that Egfp-Cetn2⁺ binding to the lumen of NPHP5^−/−; Nrl^−/− centrioles is impaired resulting in dispersion to the inner segments. OS, outer segment; CC, connecting cilium; ONL, outer nuclear layer. Scale bar, 20 µm. E–H: Cone PDE6 expression profile in untreated and treated (AAV⁺) retinas. Nphp5^+/−; Nrl^−/− (E), Nphp5^−/−; Nrl^−/− (F), Nphp5^+/−; Nrl^−/−; AAV⁺ (G), and Nphp5^−/−; Nrl^-/; AAV⁺ retina whole cryosections (H) were probed with anticone PDE6 (cPDE) antibody (red). Note the absence of expression in the double-knockout (F) and partial expression of cone PDE6 nasally in the treated retina. Indentation *, point of injection. Cryosections in A, C, and D are from mice on the Egfp-Cetn2⁺ background. Scale bar, 200 µm; enlargement, 50 µm.