Fig. 1.

Complete elimination of RGS7 preserves retina ON-BC responses to light. (A) Targeting exon 4 in the Rgs7 gene by homologous recombination is expected to truncate the protein in the middle of the DEP domain. (B) Western blot analysis of protein expression in mouse retinas. Knockout of RGS7 (RGS7^−/−) selectively reduces the levels of its interaction partners Gβ5 and R7BP (P < 0.05, t test; error bars are SEM values) without affecting the expression of proteins critical for the ON-BC function. Four retinas from separate mice in each case were used for the quantification. (C) RGS7 immunoreactivity is absent in the outer plexiform region of retina cross-sections. (Scale bar: 20 μm.) (D) RGS7-knockout mice display normal light responses as measured by ERG. A representative trace is shown out of four total experiments conducted with different mice, all yielding similar results. (E) Flash families of rod ON-BC responses in RGS7^−/− mice display normal amplitude and response kinetics. Flash strengths were 0.4, 0.7, 1.4, 2.7, 5.5, and 11 activated rhodopsin (Rh*) per rod. Records are representative of data collected across four cells from one WT and nine cells from two RGS7^−/− mice.