Abstract
Purpose: :
. Human blindness can result from functional loss of rod and/or cone photoreceptors. Loss of cone photoreceptors results in severe visual handicap in rare genetic diseases e.g. achromatopsia and in prevalent complex diseases e.g. age-related macular degeneration. Therefore, we sought to identify genes enriched in cone photoreceptors that represent therapeutic targets to slow the severity of blindness.
Methods: :
. A transgeniczebrafish line expressing green fluorescent protein (EGFP) in cone photoreceptors was used (Kennedy et al 2007, IOVS 48: 522-529). Retinas from adult fish were dissected, dissociated and sorted by FACS into EGFP+ (cone photoreceptors) and EGFP- cells. High quality RNA was isolated and microarray analysis performed.
Results: :
. RT-PCR confirmed that cone photoreceptors were highly enriched by FACS purification. Among the 15,617 probesets on the chip, 1,838 show statistically differential expression in cone photoreceptors versus the remaining non-EGFP retinal cells. Several gene ontology terms were found to be significantly overrepresented in the set of differentially expressed genes.
Conclusions: :
. Gene ontology and pathway mapping analysis will be used to select genes for functional studies. In-situ hybridization and morpholino knockdown approaches are currently been applied to identify gene subsets that are essential for cone photoreceptor function and integrity.
Keywords: gene microarray • genetics • gene/expression