Figure 4. mRNA expression of phototransduction proteins. A: The expression was determined with reverse-transcription PCR in Moorfields/Institute of Ophthalmology-Müller 1 (MIO-M1) cells. B: In human post-mortem neural retinas. The expression of the following genes was determined with RT–PCR: transducin-α (GNAZ), rod-type transducin-α (GNAT1), cone-specific transducin-α (GNAT2), retinal arrestin (cone arrestin; ARR3), and S antigen (rod photoreceptor arrestin; SAG). The data from two independent experiments (1, 2) are shown. The negative control (-) was done by adding double-distilled water instead of cDNA.