Rhodopsin formation in Drosophila is dependent on the PINTA retinoid-binding protein.

Abstract

Retinoids participate in many essential processes including the initial event in photoreception. 11-cis-retinal binds to opsin and undergoes a light-driven isomerization to all-trans-retinal. In mammals, the all-trans-retinal is converted to vitamin A (all-trans-retinol) and is transported to the retinal pigment epithelium (RPE), where along with dietary vitamin A, it is converted into 11-cis-retinal. Although this cycle has been studied extensively in mammals, many questions remain, including the specific roles of retinoid-binding proteins. Here, we establish the Drosophila visual system as a genetic model for characterizing retinoid-binding proteins. In a genetic screen for mutations that affect the biosynthesis of rhodopsin, we identified a novel CRAL-TRIO domain protein, prolonged depolarization afterpotential is not apparent (PINTA), which binds to all-trans-retinol. We demonstrate that PINTA functions subsequent to the production of vitamin A and is expressed and required in the retinal pigment cells. These results represent the first genetic evidence for a role for the retinal pigment cells in the visual response. Moreover, our data implicate Drosophila retinal pigment cells as functioning in the conversion of dietary all-trans-retinol to 11-cis-retinal and suggest that these cells are the closest invertebrate equivalent to the RPE.

• Authors: Tao Wang, Craig Montell
• Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci) Vol. 25 Issue 21 Pg. 5187-94 (May 25 2005) ISSN: 1529-2401 [Electronic] United States
• PMID: 15917458 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Drosophila Proteins
• Eye Proteins
• PINTA protein, Drosophila
• Retinol-Binding Proteins
• ninaE protein, Drosophila
• Tretinoin
• Rhodopsin

Topics

• Animals
• Animals, Genetically Modified
• Blotting, Northern (methods)
• Blotting, Western (methods)
• Chromosome Mapping (methods)
• Cloning, Molecular (methods)
• Dose-Response Relationship, Drug
• Drosophila (genetics, metabolism)
• Drosophila Proteins (genetics, metabolism, physiology)
• Electroretinography (methods)
• Eye Proteins (genetics, metabolism)
• Gene Expression Regulation, Developmental (physiology)
• Genotype
• In Situ Hybridization (methods)
• Light
• Mutation
• Pigment Epithelium of Eye (cytology, metabolism)
• Protein Binding (drug effects)
• Protein Structure, Tertiary (genetics)
• Radioligand Assay (methods)
• Retinol-Binding Proteins (genetics, physiology)
• Rhodopsin (metabolism)
• Sequence Alignment
• Tretinoin (pharmacology)