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

Curr Biol. 2015 Dec 7;25(23):3048-57. doi: 10.1016/j.cub.2015.10.018. Epub 2015 Nov 5.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

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 / genetics
  • Zebrafish / physiology*
  • Zebrafish Proteins / genetics*
  • Zebrafish Proteins / metabolism


  • Amphibian Proteins
  • Zebrafish Proteins
  • vitamin A2
  • Vitamin A
  • Cytochrome P-450 Enzyme System
  • Cyp27c1 protein, zebrafish

Associated data

  • GEO/GSE69219