Figure 1. GPR109A mRNA expression in mouse retina. A: Total RNA collected from mouse neural retina and retinal pigment epithelium (RPE)/eyecup was used for RT–PCR analysis of GPR109A mRNA expression. GPR109A expression was detected in RPE/eyecup but not in neural retina. 18S rRNA was used as an internal control. B: Localization of GPR109A mRNA transcripts was evaluated by fluorescent in situ hybridization (FISH). Hybridization of mouse retinal cryosections with GPR109A-specific antisense probe detected positive (red) labeling indicative of GPR109A expression in the RPE. No positive signal was detected in sections hybridized with sense (negative control) probe. Abbreviations: retinal ganglion cell layer (rgc); inner nuclear layer (inl); outer nuclear layer (onl). Magnification of all images in panel B is 200X.