Fig. 3.

Ectopic expression of Nrl in S-opsin-expressing cone photoreceptors. (A and B) Quantification of S-cones in the inferior domain of flat-mounted retinas from WT and BPp-Nrl/WT mice with anti-S-opsin antibody (A) revealed a 40% decrease in S-cones. Light-adapted ERG photoresponses from WT and BPp-Nrl/WT mice are shown in B [photopic b-wave (Left) and photopic b-wave at maximum intensity (Right)]. In BPp-Nrl/WT mice, ≈50% reduction in the photopic b-wave amplitude is observed compared with the WT mice. (C–N) Immunostaining of cryosections from Nrl^−/− retina show the lack of rhodopsin expression and higher S-opsin expression in the ONL (C–F). In the BPp-Nrl/Nrl^−/− retina rhodopsin expression can be detected in the ONL and the OS (G and K). Hybrid photoreceptors expressing both S-opsin (H and L) and rhodopsin can be observed in the ONL, INL, and the GCL (G–N). OS, outer segments; ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer; BBZ, bisbenzamide. (Scale bar: C–N 50 μm.) Arrows refer to colocalization of S-opsin and rhodopsin in the INL and GCL; arrowheads refer to colocalization of S-opsin and rhodopsin in the ONL.