Figure 2. Expression of RP mutants.

(a) SDS–PAGE analysis of purified WT opsin and RP-associated mutants. The gel was visualized by Coomassie staining. BSA (1 μg–200 ng) was run alongside and used for quantification purposes. (b) Fluorescence micrographs of non-permeabilized COS-7 cells expressing WT and mutant opsin as indicated. Cell surface opsin (green) was detected with the Ret-P1 antibody that recognizes an N-terminal (extracellular) epitope; nuclei (red) were stained with 4,6-diamidino-2-phenylindole (DAPI). Scale bar, 20 μm. (c) Rhodopsin immunostaining (green) in cross-sections of rhodopsin knockout mouse retinas transfected with WT, F45L, V209M and F220C rhodopsin constructs, respectively. Nuclei are stained with Hoechst (blue). Scale bar, 10 μm.