Abstract
Purpose: :
The macula is essential for precise vision; it contains many more cone photoreceptors than the peripheral retina. Cones are known to express specific opsins and other proteins that form part of the phototransduction cascade. However, relatively little is known about macular gene expression compared with the rod–rich peripheral retina. The purpose of this study was to confirm enrichment of two genes, that were macula–enriched in microarray studies, and to localise their protein products in human retina.
Methods: :
Quantitative PCR was used to confirm differential gene expression in sections of mid–peripheral retina and 2mm foveo–macular punches from human donor eyes. Protein localisation using polyclonal antibodies was carried out on human retinal cryosections.
Results: :
Enrichment of both transcripts was confirmed in human macula. One transcript was expressed at levels approaching that of red/green cone opsin. Protein products of both these genes were localised to cone photoreceptor outer segments.
Conclusions: :
The macula enriched transcripts uncovered in this study promise to provide insight into the molecular characterization of the macula’s role in precise vision. They are also excellent candidates for diseases that affect the macula and fovea such as age–related macular degeneration (AMD). Indeed, the transcripts have genomic loci that are consistent with being candidate genes for AMD.
Keywords: gene/expression • retina • age-related macular degeneration