FIGURE 5.

Relative expression of GRK1 in rods and cones of WT and GRK1⁺ retinas. A, cryosections of photoreceptor outer segments from WT and GRK1⁺ retinas, juxtaposed, then fixed, and stained with cone marker PNA (green) and GRK1 antibody (red) and imaged with confocal microscope. The positions of the cones are marked by white arrows. B, relative estimate of expression levels of GRK1 epitopes in rods and cones in WT and GRK1⁺ mouse outer segments based on quantitative immunostaining. After double staining WT and GRK1⁺ sections for GRK1 and PNA, the average pixel densities (APDU) of GRK1 immunofluorescence were quantified for PNA-negative rod (R) and PNA-positive cone (C) outer segment sections using the ImageJ Select and Measure tools in confocal stacks. The GRK1⁺/WT ratios and statistical significance were unaffected by normalization against the PNA pixel volume and densities: rods, 2.6/1 (p < 10⁻¹²); and cones, 2.8/1 (p < 10⁻⁷). Error bars show S.E.