Molecular cloning of chick pineal tryptophan hydroxylase and circadian oscillation of its mRNA levels

Jose C. Florez, Kenneth J. Seidenman, R. Keith Barrett, Ashvin M. Sangoram, Joseph S. Takahashi

Research output: Contribution to journalArticle

30 Scopus citations


We have previously shown that the level of [35S]methionine incorporation into tryptophan hydroxylase (TPH) shows a circadian rhythm in cultured chick pineal cells. The TPH protein oscillation persists in constant darkness, peaks in the early night and can be phase-shifted by light, in parallel to the effect of these treatments on melatonin synthesis. We have cloned and sequenced a full-length cDNA for chick pineal TPH. Levels of TPH mRNA show a robust diurnal oscillation both in vivo and in vitro. The rhythm in TPH mRNA also persists in constant darkness, suggesting that TPH mRNA synthesis and/or turnover is regulated by an endogenous circadian clock in cultured chick pineal cells. The circadian oscillation of TPH constitutes the first described circadian rhythm of a chick pineal gene at the mRNA level.

Original languageEnglish (US)
Pages (from-to)25-30
Number of pages6
JournalMolecular Brain Research
Issue number1
StatePublished - Nov 1996



  • Circadian rhythm
  • Melatonin
  • Molecular cloning
  • Pineal
  • Tryptophan hydroxylase

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience

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