Abstract
Abstract: :
Purpose: Rhodopsin kinase (Rk) is a light–dependent opsin phosphorylating enzyme expressed in rods, cones and pineal gland. Our goal is to demostrate that the cellular distribution of this crucial photoreceptor enzyme is governed transcriptionally. Methods: The expression of Green Fluorescent Protein (GFP) and endogenous Rk was monitored by dual wavelength immunostaining of whole globes or pineal from transgenic mice carrying a 0.11kb segment of the human Rk enhancer/promoter region upstream of GFP. Rk expression in cone subtypes was examined. Results: Immunostaining studies demostrated colocalization of GFP and Rk not only in rods, but also in cone photoreceptors in the transgenic mouse line. Immunostaining of the pineal gland sections also suggested colocalization of GFP and Rk. Conclusions:The spatial distribution of the Rk gene is transcriptionally mediated. A short sequence segment, immediately upstream of the Rk gene is likely to play a major role in governing the tissue–specific expression of Rk.
Keywords: retina • gene/expression • photoreceptors