Rod photoreceptors degeneration in the rd1 model of retinitis pigmentosa involves a cascade of events leading to proteasome dysfunction

Retinitis pigmentosa is an inherited disease with sequential retinal degeneration of rod then cone photoreceptors leading to blindness. As in this human syndrome the rd1 mouse model carries a recessive mutation in the rod-specific cGMP phosphodiesterase beta subunit gene leading to rod followed by cone photoreceptor death. The cascade of early events leading to the induction of rod cell death through apoptosis remains unknown. We report a differential whole-genome expression profiling analysis of the wild-type and rd1 mouse retinal transcriptional program using high-density oligonucleotide microarrays with a time series experiment spanning the entire rod photoreceptor degeneration process. Among the 1252 genes found to be significantly differentially expressed, a key group of 19 loci showed distinct differences in expression early in development, suggesting that these genes of clinical interest may play a fundamental role in the induction of the rod photoreceptor degeneration. Samples from purified retinal RNA from mice aged at different post-natal days were taken