Transcriptional regulation of the tyrosine hydroxylase gene by glucocorticoid and cyclic AMP.

Abstract

Glucocorticoid and cyclic AMP increase tyrosine hydroxylase (TH) activity and mRNA levels in pheochromocytoma cultures. The transcriptional activity of the TH gene, as measured by nuclear run-on assay, is also increased when cultures are treated with the synthetic glucocorticoid dexamethasone or agents that increase intracellular cyclic AMP, such as forskolin and 8-BrcAMP. Both inducers effect transcriptional changes within 10 min after treatment and are maximal after 30 min for forskolin and after 60 min for dexamethasone. The 5' flanking sequences of the TH gene were fused to the bacterial gene chloramphenicol acetyltransferase (CAT), and the hybrid gene was transfected into pheochromocytoma cultures and GH4 pituitary cells. In both cell lines, a region of the TH gene containing bases -272 to +27 conferred induction of CAT by cyclic AMP, but not by glucocorticoid. The same results were found when a region of the TH gene containing -773 to +27 was used. Thus, the sequences required for induction of TH by cyclic AMP are contained within 272 bases of 5' flanking sequence, but sequences sufficient for glucocorticoid regulation are not contained within 773 bases.The rate of biosynthesis of specific neurotransmitters can be modulated by a variety of environmental, neuronal, and hormonal stimuli. In catecholamine biosynthesis, the rate of flow through the pathway is largely dependent on the activity of the initial enzyme, tyrosine hydroxylase (TH), which is expressed in the adrenal medulla, sympathetic ganglia, and certain defined nuclei of the brain. Activity of tyrosine hydroxylase can be modulated both by changes in the synthetic rate of new tyrosine hydroxylase polypeptide and by posttranslational modification of preexisting enzyme molecules.The synthesis of TH is influenced by a variety of factors; in vivo, TH is induced in response to environmental stimuli, such as stress (1), and this induction can be mimicked pharmacologically by treatment of animals with agents that deplete cellular catecholamine stores, such as reserpine (2). In cultures of adrenal chromaffin or pheochromocytoma cells, tyrosine hydroxylase activity is induced by a number of effectors, including glucocorticoid (3, 4), cyclic AMP (5, 6), epidermal growth factor (7), and nerve growth factor (6,8,9).Whether these effectors act through similar mechanisms and whether changes are modulated transcriptionally or posttranscriptionally is not known. Using a cloned cDNA probe for TH, we have previously shown increases in the mRNA for tyrosine hydroxylase following treatment of clonal rat pheochromocytoma cells from an adrenal medullary tumor with analogs of cyclic AMP and glucocorticoid (10). The TH RNA is also increased in adrenal glands and superior cervical ganglia in vivo when animals are subjected to cold stress or reserpine treatment (11-14). In this communication, we have extended those studies by demonstrating that both glucocorticoid and cyclic AMP stimulate the transcriptional activity of the TH gene. In addition, we report that the 5...

Protein kinase A and protein kinase C signaling pathway interaction in phenylethanolamine N‐methyltransferase gene regulation

“…The upstream promoter regulatory sequences for the genes encoding TH (Lewis et al 1987;Piech-Dumas and Tank 1999;Piech-Dumas et al 2001) and DBH (Shaskus et al 1992;Kim et al 1994b) have functional CREs that are cAMP-responsive, and these CREs participate in phorbol ester-mediated PKC activation (Shaskus et al 1992;Piech-Dumas et al 2001). A canonical CRE has not been identified in the rat PNMT gene promoter (Ross et al 1990).…”

The Activity of the Highly Inducible Mouse Phenylalanine Hydroxylase Gene Promoter Is Dependent upon a Tissue-Specific, Hormone-Inducible Enhancer

“…The genes coding for tyrosine or tryptophan hydroxylase, whose proteins are closely related to PAH, show tissue-specific expression and are hormone inducible. However, the promoter structures of these three genes are different (5,32).…”

Nerve growth factor regulates tyrosine hydroxylase gene transcription through a nucleoprotein complex that contains c-Fos.

“…Inspection of the rat TH promoter (Harrington et al 1987) revealed a potential regulatory element between positions -205 and -193 with homology to a previously characterized regulatory sequence, the FSE, which is found in genes regulated during adipocyte differentiation (Distel et al 1987). Within the FSE lies a sequence homologous to the 8-bp AP-l-binding site found in both viral and animal genomes (Angel et al 1987;Lee et al 1987a, b).…”

“…Regulatory DNA regions of the rat TH promoter. The 5'-untranscribed DNA region of the rat TH promoter (Harrington et al 1987)is shown and contains a CRE {{Hyman et al 1988) located at positions -45 to -3 8 and the TH-FSE DNA element located at positions -205 to -193. The TH-FSE shares homology with the FSE2 DNA region of the adipocyte-specific gene aP2 (Distel et al 1987).…”

“…Several mechanisms have been proposed for regulating TH activity, including changes in the rate of enzyme synthesis (Hanbauer 1975;Goodman and Herschman 1978;Schubert et al 1980;Tank et al 1986), post-translational modifications of preexisting enzyme molecules (i.e., phosphorylation; Vulliet et al 1980;Campbell et al 1986), and other post-transcriptional events (Rohrer et al 1978;Acheson et al 1984). More recently, it has been demonstrated that the TH gene is transcriptionally regulated in response to EGF , glucocorticoids (Tank et al 1986;Harrington et al 1987;, and cAMP (Tank et al 1986;). The exact molecular mechanism(s) by which NGF and other transmembrane signaling agents control the TH gene is currently unknown.…”