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Cyclic AMP‐Dependent Protein Kinase Regulates Basal and Cyclic AMP‐Stimulated but Not Phorbol Ester‐Stimulated Transcription of the Tyrosine Hydroxylase Gene
Author(s) -
Kim KwangSoo,
Tinti Cristina,
Song Bai,
Cubells Joseph F.,
Joh Tong H.
Publication year - 1994
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.1471-4159.1994.63030834.x
Subject(s) - protein kinase a , microbiology and biotechnology , creb , transcription (linguistics) , forskolin , biology , reporter gene , cyclic amp response element binding protein , tyrosine hydroxylase , protein subunit , gene expression , creb1 , transcription factor , chemistry , gene , biochemistry , kinase , enzyme , linguistics , philosophy , receptor
To define the precise role of cyclic AMP (cAMP)‐dependent protein kinase (PKA) in transcriptional regulation of the tyrosine hydroxylase (TH) gene, we performed transient cotransfection analyses of a reporter construct containing the upstream 2,400 bp sequence of the rat TH gene with expression plasmids encoding a heat‐stable specific inhibitor of PKA (PKI), a mutant regulatory subunit of PKA, or the catalytic subunit of PKA. Inhibition of PKA activity by expression of either PKI or mutant regulatory subunit blocked cAMP‐stimulated induction and reduced basal transcription of the TH‐reporter construct. Expression of the catalytic subunit of PKA induced the expression of the TH‐reporter construct up to 50‐fold in a dose‐dependent manner. Primer extension analysis confirmed that PKA‐mediated induction of TH‐reporter expression occurred at the correct transcription initiation site. Expression of PKI did not affect induction following phorbol ester treatment, suggesting that PKA and protein kinase C (PKC) induce TH transcription by independent mechanisms. Finally, a double mutation within the cAMP response element (CRE) of TH2400‐CAT diminished its basal and forskolin‐stimulated transcription to the level of the promoterless plasmid, pBLCAT3, but did not alter the induction following treatment with phorbol ester, indicating that the CRE is not required for PKC‐mediated transcriptional induction. Our results indicate that PKA, via the CRE, plays a crucial role for basal and cAMP‐inducible transcription of the TH gene.