Molecular cloning of chick pineal tryptophan hydroxylase and circadian oscillation of its mRNA levels.
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.
Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208-3520, USA.
J C
JC
Florez
K J
KJ
Seidenman
R K
RK
Barrett
A M
AM
Sangoram
J S
JS
Takahashi
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D002645:Chickens; D002940:Circadian Rhythm / Q000502:physiology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D005815:Genetic Code; D015698:Genomic Library; D008969:Molecular Sequence Data; D010870:Pineal Gland / Q000201:enzymology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014365:Tryptophan Hydroxylase / Q000235:genetics / Q000378:metabolism*
D018076:DNA, Complementary; D012333:RNA, Messenger; D014365:Tryptophan Hydroxylase