Fig. 2.

Normal transducin translocation and phototransduction in Cetn1^−/− photoreceptors. (A) Light-induced translocation of transducin subunits, Tα and Tβγ. Cetn1^+/− and Cetn1^−/− mice were dark-adapted for 12 hours, or dark-adapted and exposed to light for 40 minutes. Retina cryosections were probed with anti-transducin antibodies, anti-Gnat1(Tα) and anti-Gngt1 (Tγ). Light-induced translocation of Tα and Tγ was indistinguishable in the two genotypes. (B) Upregulation of CETN2 in Cetn1^−/− knockout retinas. cDNA from Cetn1^WT/WT;iCre75+, Cetn1^3lox/3lox;iCre75+, Cetn1^+/+, and Cetn1^−/− retinas was amplified under real-time conditions (see Materials and Methods). No significant difference in Cetn2 expression was detected in Cetn1^3lox/3lox;iCre75+ (N = 2) compared with WT retinas. In global knockouts, Cetn2 was upregulated over 30% (N = 2) suggesting compensation for loss of the CETN1 isoform. (C) Electroretinogram of wild-type, heterozygous and homozygous Cetn1 rod-specific deletion retinas. (D) Immunoblots of outer segment polypeptides unaffected (rhodopsin, recoverin, PDE6, rod Tα, and rod arrestin), and downregulated (GRK1 and PDE6D) by Cetn1 deletion.