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R.M. Kelln, V. Vasireddy, R. Darrow, D.T. Organisciak, R. Ayyagari, P. Wong; Functional Analysis of a Novel Rat Retinal Expressed Gene Associated With Light–Induced Retinal Degeneration . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3083.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Many genes have been identified which when defective result in retinal degeneration however the precise pathways that initiate and underlie any particular tissue degeneration are not known. In an effort to identify genes involved in this retinal tissue degeneration process we screened a rat retinal cDNA library for genes that are differentially expressed during light–induced retinal degeneration. An uncharacterized gene, 1363, isolated from this cDNA library screen was chosen for further study. Methods:Northern analysis was performed on retinal RNA isolated from rats exposed to varying durations of light exposure to confirm the differential expression profile of 1363. To obtain the full–length transcript of 1363 a combination of 5’ RACE and bioinformatics were used. Homology searches were performed using the nucleotide sequence as well as the putative protein sequence to determine gene conservation across various organisms. Bioinformatic analysis of the protein sequence identified two nuclear localization signals (NLS) in the C–terminus of the protein. The functionality of these sites was analyzed by determining localization of wildtype and mutant GFP–1363 fused constructs in Cos–7 cells. Results: Northern analysis indicates that 1363 is expressed in the dark–reared rat retina and repressed after short exposures to green light. The gene structure of 1363 consists of two exons separated by a large intron. The 1363 nucleotide and protein sequence are highly conserved among numerous species. Bioinformatic analysis of the protein sequence identified three potential functional domains corresponding to two NLSs as well as a BTB/POZ domain, which is a protein–protein interaction motif. Mutation of the NLS regions lead to aberrant cellular distribution of the 1363 protein in Cos–7 cells. Conclusions: Being that the 1363 gene was isolated from a screen for genes involved in retinal degeneration, it may have a unique and, as of yet, unknown role in the degenerative process. The characterization of aspects of this gene will enhance our knowledge of cellular functions in the normal retinal as well as the degenerative retina, which is important in the overall understanding of retinal disease.
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