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Involvement of NF‐Y and Sp1 in basal and cAMP‐stimulated transcriptional activation of the tryptophan hydroxylase ( TPH ) gene in the pineal gland
Author(s) -
Côté F.,
Schussler N.,
Boularand S.,
Peirotes A.,
Thévenot E.,
Mallet J.,
Vodjdani G.
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00890.x
Subject(s) - caat box , biology , microbiology and biotechnology , tryptophan hydroxylase , promoter , response element , transcription (linguistics) , transcription factor , gene , transcriptional regulation , gene expression , genetics , serotonin , receptor , linguistics , philosophy , serotonergic
The expression of the tryptophan hydroxylase (TPH) gene, encoding the rate‐limiting enzyme of serotonin biosynthesis, is tightly regulated both at the transcriptional and at the post‐transcriptional levels. In the pineal gland, transcription of the gene is activated in response to an intracellular circadian increase of the cAMP concentration. We have previously shown that transcription of a 2.1‐kb fragment of the human TPH promoter is induced by cAMP, although it lacks the canonical cAMP responsive element, CRE. The minimal promoter (−73/+29) has only weak transcriptional activity but is responsive to cAMP. It contains an inverted CCAAT box, which was demonstrated to be involved in this response. Here, we have extended our investigation to the functional features of the inverted CCAAT box in the −252/+29 TPH promoter, which has a higher basal activity. We show that an additional cis ‐acting sequence, the adjacent GC‐rich region, cooperates with the inverted CCAAT box for the full activation of basal transcription, and that both elements are essential for the full cAMP response. We also show that in pinealocytes, NF‐Y and Sp1 transactivators bind the inverted CCAAT box and GC‐rich‐region, respectively. These factors participate in a novel pathway for the cAMP‐mediated response of the TPH promoter, which is independent of the canonical CRE‐mediated response.