Purchase this article with an account.
S. C. Khani, J. E. Young, Z. Khani-Oskouie, G.-H. Peng, S. Chen; Retiniods Regulate Rhodopsin Kinase Transcription via Receptor-Modulated Promoter Activity. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1677.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Retinoids are powerful modulators of gene expression in a variety of cell types including photoreceptors where they are found in abundance. Many photoreceptor genes and promoters have retinoid response elements but relatively little is known about whether or not these sites are responsive to retinoid ligand signaling prior to and after differentiation. The purpose of the current study is to demonstrate the presence of active retinoid signaling pathways in the developing and mature photoreceptor cells using rhodopsin kinase (RK or GRK1) as a target gene model.The RK gene contains a uniquely compact promoter and plays a crucial role in photoreceptor recovery.
Bioinformatic, gel retardation, yeast one-hybrid and chromatin immunoprecipitation studies were used to identify retinoid receptor binding sites on the RK promoter. RK expression levels, promoter activity and responsiveness to retinoids were analyzed using quantitative RT-PCR, immunostaining and immunoblotting of retinoblastoma cells or in RK-GFP transgenic mice. RK promoter fragments containing deletions were linked to luciferase reporter and tested by transient transfections for promoter activity and retinoid responsiveness.
Several putative retinoid response elements were found to interact with retinoid receptors primarily retinoid-X-receptor gamma (RXRγ). Chromatin immunoprecipitation further confirmed interaction of this retinoid receptor with Rk promoter in mouse retina. Exposure to retinoids stimulated expression of the endogenous Rk gene along with RK promoter-driven GFP or luciferase reporters not only in the retinoblastoma cells but also whole retinas of RK-GFP transgenic mice. The results of deletion/mutation analyses of the RK promoter suggested the presence of multiple retinoid responsive sites.
In photoreceptors, retinoid receptor pathways modulate RK gene expression prior and after differentiation. Since RK promoter has been used in designing gene therapy for photoreceptor diseases, retinoids may prove useful in modulating RK-driven expression of therapeutic genes.
This PDF is available to Subscribers Only