PURPOSE To identify novel transcriptional regulators of rhodopsin expression as a model for understanding photoreceptor-specific gene regulation. METHODS A bovine retinal cDNA library was screened in a yeast one-hybrid assay, with a 29-bp bovine rhodopsin promoter fragment as bait. Expression studies used RT-PCR and beta-galactosidase (LacZ) histochemistry of retinas from transgenic mice hete...

A Drosophila mutant (ninaAP228) that is low in rhodopsin concentration but identical to the wild-type fly in photoreceptor morphology has been isolated. R1-6 photoreceptors of the mutant differ from those of wild type in that (a) the prolonged depolarizing afterpotential (PDA) is absent, (b) concentrations of rhodopsin and opsin are substantially reduced, and (c) intramembrane particle density ...

A heptahelical transmembrane bundle is a common structural feature of G-protein-coupled receptors (GPCRs) and bacterial retinal-binding proteins, two functionally distinct groups of membrane proteins. Rhodopsin, a photoreceptor protein involved in photopic (rod) vision, is a prototypical GPCR that contains 11-cis-retinal as its intrinsic chromophore ligand. Therefore, uniquely, rhodopsin is a G...

The effect of cholesterol on rod outer segment disk membrane structure and rhodopsin activation was investigated. Disk membranes with varying cholesterol concentrations were prepared using methyl-cyclodextrin as a cholesterol donor or acceptor. Cholesterol exchange followed a simple equilibrium partitioning model with a partition coefficient of 5.2 0.8 in favor of the disk membrane. Reduced cho...

PURPOSE To isolate and characterize the rhodopsin cDNA from the fish, Astyanax fasciatus, and to determine the effect of tyrosine 261 on its spectral tuning. METHODS The rhodopsin cDNA was cloned using reverse transcription-polymerase chain reaction amplification and then sequenced. A mutant, Y261F, was generated by site-directed mutagenesis. Both wild type and mutant were transiently express...

The capacity to generate 11-cis retinal from retinoids arising naturally in the eye was examined in the retina of the bullfrog, Rana catesbeiana. Retinoids, co-suspended with phosphatidylcholine, were applied topically to the photoreceptor surface of the isolated retina after substantial bleaching of the native visual pigment. The increase in photoreceptor sensitivity associated with the format...

Light-activated, ion-pumping rhodopsins are broadly distributed among many different bacteria and archaea inhabiting the photic zone of aquatic environments. Bacterial proton- or sodium-translocating rhodopsins can convert light energy into a chemiosmotic force that can be converted into cellular biochemical energy, and thus represent a widespread alternative form of photoheterotrophy. Here we ...

Most vertebrate retinas contain two types of photoreceptor cells, rods and cones, which show different photoresponses to mediate scotopic and photopic vision, respectively. These cells contain different types of visual pigments, rhodopsin and cone visual pigments, respectively, but little is known about the molecular properties of cone visual pigments under physiological conditions, making it d...

Photoreceptor development begins in the larval eye imaginal disc, where eight distinct photoreceptor cells (R1-R8) are sequentially recruited into each of the developing ommatidial clusters. Final photoreceptor differentiation, including rhabdomere formation and rhodopsin expression, is completed during pupal life. During pupation, spalt was previously proposed to promote R7 and R8 terminal dif...

Mice carrying a targeted disruption of the rhodopsin gene develop a severe degenerative retinopathy, failing to elaborate rod photoreceptor outer segments (ROS), having no recordable rod electroretinogram (ERG) and losing all of their rod cells over a period of approximately 12 weeks. Murine and human rhodopsins differ in their amino acid sequences. Whether, or to what extent, such variability ...