Title: Cyp27c1 Red-Shifts the Spectral Sensitivity of Photoreceptors by Converting Vitamin A1 into A2.

Authors: Enright, Jennifer M; Toomey, Matthew B; Sato, Shin-ya; Temple, Shelby E; Allen, James R; Fujiwara, Rina; Kramlinger, Valerie M; Nagy, Leslie D; Johnson, Kevin M; Xiao, Yi; How, Martin J; Johnson, Stephen L; Roberts, Nicholas W; Kefalov, Vladimir J; Guengerich, F Peter; Corbo, Joseph C

Published In Curr Biol, (2015 Dec 07)

Abstract: Some vertebrate species have evolved means of extending their visual sensitivity beyond the range of human vision. One mechanism of enhancing sensitivity to long-wavelength light is to replace the 11-cis retinal chromophore in photopigments with 11-cis 3,4-didehydroretinal. Despite over a century of research on this topic, the enzymatic basis of this perceptual switch remains unknown. Here, we show that a cytochrome P450 family member, Cyp27c1, mediates this switch by converting vitamin A1 (the precursor of 11-cis retinal) into vitamin A2 (the precursor of 11-cis 3,4-didehydroretinal). Knockout of cyp27c1 in zebrafish abrogates production of vitamin A2, eliminating the animal's ability to red-shift its photoreceptor spectral sensitivity and reducing its ability to see and respond to near-infrared light. Thus, the expression of a single enzyme mediates dynamic spectral tuning of the entire visual system by controlling the balance of vitamin A1 and A2 in the eye.

PubMed ID: 26549260

MeSH Terms: Amphibian Proteins/genetics*; Amphibian Proteins/metabolism; Animals; Cytochrome P-450 Enzyme System/genetics*; Cytochrome P-450 Enzyme System/metabolism; Infrared Rays; Photoreceptor Cells, Vertebrate/physiology; Rana catesbeiana/genetics; Rana catesbeiana/physiology*; Transcriptome; Visual Perception; Vitamin A/analogs & derivatives*; Vitamin A/metabolism*; Zebrafish Proteins/genetics*; Zebrafish Proteins/metabolism; Zebrafish/genetics; Zebrafish/physiology*