Abstract
Abstract: :
Purpose: TULP1 is a member of the TULP family of proteins with unknown function and is expressed specifically in photoreceptor cells. Mutations in TULP1 cause autosomal recessive retinitis pigmentosa and Tulp1 knockout mice develop an early–onset, progressive photoreceptor degeneration. Our previous data indicate that TULP1 may be involved in the movement of proteins from the inner segment to the outer segment of photoreceptors. To better understand the pathogenic mechanism and potential pathways involved in photoreceptor degeneration in tulp1–/– mice, we are comparing the gene expression profile in the tulp1–/– retinas to wild–type (WT) retinas. Methods: RNA was isolated from the retinas of tulp1–/– and WT littermate mice at P15. The RNA was used to make biotinylated cRNA for gene chip hybridization. cRNA was hybridized to Mouse Genome 430 2.0 arrays (Affymetrix) containing ∼45,000 probe sets representing ∼39,000 transcripts. Scanning of probe arrays and data analysis were performed according to Affymetrix protocols. Only the transcripts between experimental groups that have more than a 2–fold change and a p–value less than 0.005 are reported. Results:We identified 97 transcripts that were significantly altered in the tulp1–/– retinas as compared to WT retinas. For transcripts that were decreased in tulp1–/– retinas, the biological processes they are associated with include membrane trafficking, cargo binding and dynein–based movement. The majority of transcripts that were increased in tulp1–/– retinas were unknown, novel cDNAs. We are currently using real–time RT–PCR to verify and quantify our array data and immunohistochemistry to examine spatiotemporal changes in expression patterns. Conclusions: Lack of Tulp1 changes the gene expression profile of the retina. Our results indicate that transcripts involved in vesicular movement are downregulated in tulp1–/– retinas and suggest that photoreceptor degeneration in the tulp1–/– mouse may be due to a disruption of the intracellular protein transport pathway. Support: CCF, FFB
Keywords: gene microarray • retinal degenerations: cell biology • gene/expression