DISTRIBUTION OF FGF-5 IN THE RHESUS MACAQUE RETINA

Purpose. To determine the distribution of mRNA transcribed from the FG F-5 gene and the distribution of FGF-5 protein in the normal adult ret ina of the rhesus macaque. Methods. Freshly enucleated globes from rhe sus macaque were prepared for Northern blot analysis, in situ hybridiz ation, and immunohistochemical studies. A 350 base pair sequence from the human FGF-5 was subcloned and used to prepare S-35-labeled cRNAs f or Northern and in situ experiments. Antipeptide antibodies were raise d against an aminoterminal sequence as well as an internal sequence an d were affinity purified on recombinant FGF-5 coupled to AffiGel-10. T he specificity of antibody probes was verified by dot blot and Western blot analyses. Results. Ganglion cells and photoreceptors express the highest levels of FGF-5 mRNA, although all neurons and the retinal pi gment epithelium (RPE) were clearly labeled. Immunohistochemical stain ing similarly revealed a widespread distribution of the protein, with prominent labeling observed in photoreceptor inner segments, especiall y in cone cells. Plexiform layers and RPE cells were also clearly labe led. Conclusions. Clear evidence was established for the expression of FGF-5 in the retina, where it may play an important extracellular rol e as a secreted member of the FGF gene family.