Figure 3. mRNA expression of opsins in Moorfields/Institute of Ophthalmology-Müller 1 (MIO-M1) cells and human retinas. A: The expression of the following genes was determined with real-time PCR in MIO-M1 cells and (B) in neural retinal tissues from post-mortem donors. Long- and midwave-sensitive cone opsin (OPN1LW+MW), shortwave-sensitive cone opsin (OPN1SW), rhodopsin (OPN2), panopsin (OPN3), melanopsin (OPN4), neuropsin (OPN5), retinal G protein-coupled receptor (RGR), and peropsin (RRH). In addition, the detection of hypoxanthine phosphoribosyl-transferase (HPRT) transcripts is shown. The data from two independent experiments (1, 2) are shown. The negative control (-) was done by adding double-distilled water instead of cDNA. C: A plasmid (pBSII SK+OPN4) containing the open reading frame of melanopsin (OPN4; 1) was used as positive control for the PCR experiments. D: MIO-M1 cells that were cultured for 18 h in the absence (1) and presence (2), respectively, of fetal bovine serum (10%) contained transcripts for OPN4. E: Relative expression level of opsins in MIO-M1 cells and postmortem neural retinal tissues. The data were determined by real-time-PCR. The bars represent the cycle numbers required to detect the transcripts (relative to the cycle number for the detection of HPRT mRNA). The data are the means±standard error of the mean (SEM) of seven independent experiments. *P value (p)<0.001. F: Mean cycle threshold (CT) values (±SEM) for each gene determined by real-time PCR.