Circadian regulation of iodopsin gene expression in embryonic photoreceptors in retinal cell culture

Neuron. 1993 Apr;10(4):579-84. doi: 10.1016/0896-6273(93)90161-j.


A circadian clock regulates a number of diverse physiological functions in the vertebrate eye. In this study, we show that mRNA for the red-sensitive cone pigment, iodopsin, fluctuates with a circadian rhythm in chicken retina. Transcript levels increase in the late afternoon just prior to the time of cone disc shedding. Furthermore, iodopsin mRNA levels are regulated similarly by a circadian oscillator in primary cultures of dispersed embryonic chick retina. Nuclear run-on experiments show that the circadian regulation of iodopsin transcript abundance occurs at the level of gene transcription. Our results provide a demonstration of clock-regulated gene expression in a vertebrate preparation maintained in cell culture.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Chick Embryo
  • Circadian Rhythm*
  • Gene Expression*
  • Photoreceptor Cells / embryology
  • Photoreceptor Cells / physiology*
  • RNA, Messenger / metabolism
  • Retina / cytology
  • Retina / embryology*
  • Retinal Pigments / genetics*
  • Rod Opsins*
  • Transcription, Genetic


  • RNA, Messenger
  • Retinal Pigments
  • Rod Opsins
  • iodopsin