Chicken pineal Cry genes: Light-dependent up-regulation of cCry1 and cCry2 transcripts

Kazuyuki Yamamoto, Toshiyuki Okano, Yoshitaka Fukada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Citations (Scopus)


Vertebrate cryptochrome homologs (CRYs) are negative regulators for the transcription/translation-based autoregulatory feedback loop of the circadian clock. In this study we identified two Cry genes in the chicken, cCry1 and cCry2, which are expressed in the pineal gland. Messenger RNA levels of both cCry1 and cCry2 displayed circadian oscillation in cultured pineal cells under light/dark and constant darkness conditions. Noticeably, their mRNA levels during the light period were significantly higher than those in the dark, indicating light-dependent up-regulation of the two Cry genes mediated by photoreceptor(s) intrinsic to the chick pineal cells. These cCRYs inhibited E-box element-dependent cBMAL1/2-cCLOCK-induced transcription, suggesting that the chick pineal circadian oscillator is composed of molecules that are functionally similar to those of mammals but are subject to light-regulation distinct from the mammalian clockwork.

Original languageEnglish
Pages (from-to)13-16
Number of pages4
JournalNeuroscience Letters
Issue number1-2
Publication statusPublished - 2001 Nov 2
Externally publishedYes


  • Chicken
  • Circadian clock
  • Clock gene
  • Cryptochrome
  • Pineal gland
  • Transcriptional inhibitor

ASJC Scopus subject areas

  • Neuroscience(all)


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