Abstract
Abstract: :
Purpose: To identify genes that regulate cone photoreceptor development through their interaction with Nr2e3. Methods: The rd7/rd7 mouse, harboring a mutation in Nr2e3, was used to study cone photoreceptor development and function. BrdU incorporation was analyzed on mice at various time points to determine if the increase in cone cells observed in rd7 mice was due to an increase rate or a prolonged window of cell proliferation. Real time PCR analysis was performed using cDNA from postnatal day 2 (P2) and P30 eyes. Over 100 genes involved in retina development and function were analyzed. Eight control genes were also analyzed with each experiment to monitor PCR fidelity. Subtractive hybridization was performed using cDNA libraries created from P0 and P2 eyes of rd7/rd7 and C57BL6/J control mice. Subtraction was performed in both directions. Subtracted libraries were cloned and sequenced to identify unique cDNAs in each population. Genes identified by subtractive hybridization were subsequently tested by real time PCR analysis. Results: BrdU incorporation studies demonstrate that the increased number of cone cells in rd7 retinas is due to prolonged proliferation of cone photoreceptor cells. From the differential gene expression experiments, 3 developmental, 6 visual pathway, 2 cell fate, 2 structure/support, and 10 orphan receptor genes were identified as being misregulated in rd7 retinas. At P2, 14 genes identified by real time PCR analysis appear to be misregulated. The expression of these genes was downregulated in rd7 mice compared to wildtype. In contrast, at P30, 16 genes were misregulated and most of these genes were upregulated in rd7 mice. Conclusions: Genes misregulated in rd7 may provide entry points for pathways in which Nr2e3 functions during photoreceptor development and visual transduction in the adult retina.
Keywords: photoreceptors • gene/expression • retinal development