Figure 3.

RNase protection, Northern blot analysis, and in situ hybridization localize peropsin transcripts to the RPE. (A) Total RNA from the indicated adult mouse tissues was used for RNase protection with a mouse peropsin probe. Peropsin transcripts are detected only in the eye. A control reaction with an RNA polymerase II probe is shown at bottom. (B) Northern blot of total RNA from the indicated bovine tissues was hybridized to a probe encompassing the human peropsin coding region. Peropsin transcripts are detected only in the RPE. Arrowheads indicate the mobilities of the ribosomal RNAs. (C) In situ hybridization using a digoxigenin-labeled mouse peropsin probe localizes peropsin transcripts in the adult rat to the RPE (arrowhead). (Left) Antisense probe. (Right) Sense probe. Albino rats were used for this experiment so that RPE melanin would not obscure the signal. At long substrate incubation times, a faint hybridization signal is seen in the inner nuclear layer; the origin of this signal is not known. Arrowhead, nucleus of RPE cell. OS, outer segments; ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer.