Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A genomic clone for rat tyrosine hydroxylase (TH) was isolated and a fragment containing 503 bp upstream of the transcription start site was sequenced. The BamHI/AluI fragment was inserted into a plasmid carrying the coding sequence for bacterial chloramphenicol acetyltransferase (CAT). Another construct with the 5' sequence truncated to -151 bp also was prepared. When these were introduced into several mammalian cell lines, including C6 glioma, BE(2) neuroblastoma, CV-1 or Ltk- fibroblasts, different basal levels of CAT expression were observed. In the fibroblast lines, THCAT constructs were not expressed unless the cells were treated with forskolin or TPA. However, the low basal expression was not correlated to endogenous expression as THCAT constructs expressed comparably in BE(2)C, HeLa, and C6 glioma. Treatment of any of the cell lines with forskolin, TPA, or a combination of the two agents stimulated the expression by at least two-fold in all cell lines and the maximally induced levels were at least 10-fold over promoterless controls. These data indicate that the essential promoter elements as well as those conferring responsivity to cyclic AMP reside within 151 bp of the transcription start site. However, the array of elements regulating cell-type expression lie, at least in part, beyond the 500-bp region examined. Further, a role for phosphorylation in the regulation of basal and induced transcription of TH is suggested.
J Mol Neurosci 1991
PMID:Effects of second messenger system activation on functional expression of tyrosine hydroxylase fusion gene constructs in neuronal and nonneuronal cells. 168 57

This article focuses on the role of protein phosphorylation, especially that mediated by protein kinase C (PKC), in neurotransmitter release. In the first part of the article, the evidence linking PKC activation to neurotransmitter release is evaluated. Neurotransmitter release can be elicited in at least two manners that may involve distinct mechanisms: Evoked release is stimulated by calcium influx following chemical or electrical depolarization, whereas enhanced release is stimulated by direct application of phorbol ester or fatty acid activators of PKC. A markedly distinct sensitivity of the two pathways to PKC inhibitors or to PKC downregulation suggests that only enhanced release is directly PKC-mediated. In the second part of the article, a framework is provided for understanding the complex and apparently contrasting effects of PKC inhibitors. A model is proposed whereby the site of interaction of a PKC inhibitor with the enzyme dictates the apparent potency of the inhibitor, since the multiple activators also interact with these distinct sites on the enzyme. Appropriate PKC inhibitors can now be selected on the basis of both the PKC activator used and the site of inhibitor interaction with PKC. In the third part of the article, the known nerve terminal substrates of PKC are examined. Only four have been identified, tyrosine hydroxylase, MARCKS, B-50, and dephosphin, and the latter two may be associated with neurotransmitter release. Phosphorylation of the first three of these proteins by PKC accompanies release. B-50 may be associated with evoked release since antibodies delivered into permeabilized synaptosomes block evoked, but not enhanced release. Dephosphin and its PKC phosphorylation may also be associated with evoked release, but in a unique manner. Dephosphin is a phosphoprotein concentrated in nerve terminals, which, upon stimulation of release, is rapidly dephosphorylated by a calcium-stimulated phosphatase (possibly calcineurin [CN]). Upon termination of the rise in intracellular calcium, dephosphin is phosphorylated by PKC. A priming model of neurotransmitter release is proposed where PKC-mediated phosphorylation of such a protein is an obligatory step that primes the release apparatus, in preparation for a calcium influx signal. Protein dephosphorylation may therefore be as important as protein phosphorylation in neurotransmitter release.
Mol Neurobiol 1991
PMID:The role of protein kinase C and its neuronal substrates dephosphin, B-50, and MARCKS in neurotransmitter release. 168 57

Improvements in the sensitivity of non-radioactive in situ hybridization histochemistry methods for detection of mRNA now make it feasible to combine the use of non-radioactive and radioactive in situ methods to visualize two mRNAs on the same tissue section. The method reported here allows the simultaneous detection of two mRNAs in one cell and therefore is ideally suited to the studies of co-expression. Here we demonstrate the co-expression of tyrosine hydroxylase (TH) mRNA and cholecystokinin (CCK) mRNA in the ventral mesencephalic dopaminergic neurones of the rat. The distribution of dopaminergic neurones containing both TH and CCK transcripts suggests, on the basis of earlier anatomical studies that these CCK/TH-containing doubled-labelled cells project mainly to the striatal matrix. Dopamine neurones believed to project to the patch compartment did not contain CCK mRNA.
Brain Res Mol Brain Res 1991 Jan
PMID:Co-expression of cholecystokinin mRNA and tyrosine hydroxylase mRNA in populations of rat substantia nigra cells; a study using a combined radioactive and non-radioactive in situ hybridization procedure. 170 77

The levels of tyrosine hydroxylase and galanin mRNA were measured by in situ hybridization histochemistry in the rat locus coeruleus after repeated (21 days) administration of desmethylimipramine (10 mg/kg/day), of reserpine (0.25 mg/kg/day), of coadministered desmethylimipramine and reserpine, or of vehicle. Reserpine administration resulted in increased levels of both tyrosine hydroxylase and galanin mRNAs in locus coeruleus neurons as compared to vehicle-treated controls. Administration of desmethylimipramine alone failed to alter either the tyrosine hydroxylase or galanin mRNA. However, coadministration of desmethylimipramine with reserpine blocked the elevation in tyrosine hydroxylase mRNA induced by reserpine alone.
Brain Res Mol Brain Res 1991 Jul
PMID:Repeated administration of desmethylimipramine blocks the reserpine-induced increase in tyrosine hydroxylase mRNA in locus coeruleus neurons of the rat. 171 8

Primary cultures of chromaffin cells were prepared from bovine adrenal medullae and the levels of mRNA for tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) determined. The cells expressed moderate levels of TH mRNA and low levels of PNMT mRNA. The latter appeared to be more sensitive than TH mRNA to variations in the culture medium. The treatment of cultures with agents that activate signal transduction pathways, forskolin or phorbol esters, dramatically enhanced the expression of both mRNAs. The forskolin-induced increases in the steady-state levels of TH and PNMT mRNAs occurred rapidly and were apparent within 5 hours. These data suggest that the TH and PNMT genes can be regulated by second messengers. In contrast, dexamethasone treatment dramatically increased PNMT mRNA with no change in TH mRNA. The increase in PNMT mRNA was apparent within 6 hours of addition of the drug to the culture medium.
J Mol Neurosci 1991
PMID:Differential and coordinate regulation of TH and PNMT mRNAs in chromaffin cell cultures by second messenger system activation and steroid treatment. 172 44

Several genomic clones encoding carboxypeptidase-E (CPE) have been isolated and partially sequenced. Southern blot analysis indicates that a single copy of this gene is present in the rat genome. The entire gene spans approximately 50 kilobases and consists of nine exons, each of which contains protein-coding regions. Only one of the exon/intron junctions of the rat CPE gene is present in a comparable position within the genes for carboxypeptidase-A and -B, both of which are only 17-21% homologous to CPE at the amino acid level. Nuclease protection analysis shows that alternative splicing of exons 7, 8, and 9 does not occur, indicating that the heterogeneity of the C-terminal region of CPE is due to posttranslational processing. Primer extension and nuclease protection analyses have identified the 5' end of CPE mRNA to be 105 nucleotides up-stream from the ATG used for protein translation. The 5' flanking region does not contain TATA and/or CCAAT boxes in the near vicinity of the transcription initiation site. The 5' flanking region is GC rich, containing 70% GC residues over nucleotides -1 to -150 (relative to the transcription initiation site). Putative consensus sites for the enhancer elements SP-1, NF-1, Pan-1, and AP-2 are present in the region from -60 to -330. Since this report describes the first neuropeptide-processing enzyme gene to be partially sequenced, it is not possible to compare the sequence with those of other processing enzymes that show similar tissue-specific expression. However, comparison of the CPE sequence with 5' flanking regions of other neuroendocrine genes has revealed a short region (12-18 nucleotides) that is highly conserved among CPE, neuropeptide-Y, oxytocin, insulin, and tyrosine hydroxylase genes.
Mol Endocrinol 1991 Sep
PMID:Structural characterization of the rat carboxypeptidase-E gene. 177 Sep 52

Using a solution hybridization-S1 nuclease protection assay, we quantitatively studied tyrosine hydroxylase mRNA (mRNATH) in catecholaminergic cells of the substantia nigra, hypothalamus, superior cervical ganglion, and adrenal of male rats from early neonatal life to old age. Throughout this time, the lowest level of mRNATH in any tissue was found in the youngest animals, and their development was associated with an increase in the quantity of mRNATH. However, the extent of the increase as well as the pattern of change was dependent on the tissue. The amount of mRNATH in the substantia nigra of 1-day-old pups was 162 +/- 7 attomoles (mean and S.E.M.), increasing to 877 +/- 39 amol at 14 days of age. Then, the amount fell to 480 +/- 25 amol at 6 weeks of age, but changed little between 6 weeks and 23 months of age. In the hypothalamus of 1-day-old pups, the quantity of mRNATH was 24 +/- 3 amol, increasing to 60 +/- 6 amol at 2 weeks and changed little thereafter. mRNATH in the superior cervical ganglion increased gradually until 10 months of age; at which time the amount was 3 times that of neonatal animals. In the adrenal, mRNATH increased continuously throughout the period of observation. The amount of mRNATH in the adrenal of 23-month-old animals was 25 times that in the adrenal of 4-day-old pups. These data suggest that tyrosine hydroxylase gene expression does not diminish in aged rats.
Brain Res Mol Brain Res 1990 Jan
PMID:Quantitative study of tyrosine hydroxylase mRNA in catecholaminergic neurons and adrenals during development and aging. 196 14

Tyrosine hydroxylase is activated and phosphorylated following treatment of PC-12 cells with bradykinin. In order to determine the mechanisms by which this occurs, we have evaluated the second messenger systems that may be responsible for this activation and phosphorylation. Inositol phosphates appear to play an important role in the activation and phosphorylation of tyrosine hydroxylase because bradykinin treatment significantly increased the formation of [3H]inositol phosphates and the concentration of intracellular free calcium ([Ca2+]i) in PC-12 cells. The uptake of extracellular 45Ca2+ into PC-12 cells at 1 min was significantly increased (107%) by bradykinin treatment and this increase was blocked by La3+, an inorganic calcium channel inhibitor, but not by nifedipine, an inhibitor of voltage-dependent calcium channels. The activation of tyrosine hydroxylase in PC-12 cells following bradykinin treatment was partially inhibited by La3+. Additivity experiments were performed to evaluate whether the activation and phosphorylation of tyrosine hydroxylase in PC-12 cells following treatment with bradykinin (10 microM) was similar to the activation and phosphorylation of tyrosine hydroxylase in PC-12 cells following treatment with dibutyryl cAMP (2 mM), 4 beta-phorbol-12 beta-myristate-13 alpha-acetate (PMA) (2 microM), and high K+ (56 mM). The combination of bradykinin and PMA produced additive effects, indicating that the activation of tyrosine hydroxylase by treatment with these two compounds was through different mechanisms. Furthermore, exposure of PC-12 cells to bradykinin did not increase intracellular cAMP levels. The combination of bradykinin and PMA treatments produced only partial additivity in tyrosine hydroxylase activity and phosphorylation. No additivity was produced with bradykinin and high K-treatment. Phosphopeptide analysis was performed on tyrosine hydroxylase obtained from PC-12 cells treated with bradykinin. Bradykinin treatment produced a significant incorporation of [32P]-phosphate into two phosphopeptides of tryptically digested tyrosine hydroxylase. One of these peptides corresponds to a peptide obtained by trypsinization of purified tyrosine hydroxylase that is phosphorylated by purified calcium/calmodulin-dependent protein kinase. The other 32P-tyrosine hydroxylase-peptide obtained from PC-12 cells treated with bradykinin corresponds to the phosphorylation site obtained during PMA stimulation of PC-12 cells. These results indicate that bradykinin treatment increases intracellular inositol phosphates, calcium, and possibly diacylglycerol levels in PC-12 cells. These effects could then increase calcium/calmodulin-dependent protein kinase activity and possibly calcium/phospholipid-dependent protein (protein kinase C) activity, resulting in increased phosphorylation and activity of tyrosine hydroxylase.
Mol Pharmacol 1990 Jan
PMID:Regulation of tyrosine hydroxylase activity in pheochromocytoma PC-12 cells by bradykinin. 196 17

The identity of the neuronal nicotinic alpha-bungarotoxin (alpha-BGT) site, which appears to be distinct from the functional nicotinic receptor, is unclear. Recent work in our laboratory has shown that the thymus-derived polypeptide thymopoietin potently and specifically interacts at the nicotinic alpha-BGT site in brain. The present results show that thymopoietin also interferes with the binding of 125I-alpha-BGT to chromaffin cells in culture; a dose-dependent inhibition in binding was observed, with an IC50 of 10(-8) M. To assess the long term effect(s) of thymopoietin in nervous tissue, chromaffin cells were exposed to the polypeptide for varying periods of time. Incubation of the cells in culture with thymopoietin (10(-9) to 3 x 10(-7) M) for 2 to 7 days resulted in an approximate 3-fold increase in alpha-BGT binding. Saturation analysis indicated this was due to an increase in the Bmax. The thymopoietin-induced increase in binding could be reversed with nicotine: thus, the sites can be regulated by a nicotinic receptor ligand. Although thymopoietin potently interacted at the nicotinic alpha-BGT receptor, nicotinic receptor responsiveness was not affected after short or long term exposure to the peptide. Neither basal nor nicotinic receptor-stimulated tyrosine hydroxylase activity was altered by thymopoietin. As well, resting and acetylcholine-evoked noradrenaline release remained similar to control after exposure of the cells to the polypeptide. These results indicate that the thymic polypeptide thymopoietin specifically interacts with the nicotinic alpha-BGT receptor population and, furthermore, can regulate the toxin binding sites in chromaffin cells in culture.
Mol Pharmacol 1990 Jan
PMID:Thymopoietin, a thymic polypeptide, regulates nicotinic alpha-bungarotoxin sites in chromaffin cells in culture. 837 21

1. The studies described herein were designed to test the hypothesis that a neuroleptic, haloperidol, may alter the level of expression of the tyrosine hydroxylase and cholecystokinin genes in discrete brain regions. 2. In situ hybridization was employed to quantitate changes in concentration of mRNA for tyrosine hydroxylase and cholecystokinin in the ventral tegmental area, substantia nigra, and locus ceruleus after acute or chronic treatment with haloperidol or vehicle. 3. Haloperidol had no effect on the level of tyrosine hydroxylase or cholecystokinin mRNAs, in the ventral tegmentum, substantia nigra, or locus ceruleus, at either 3 or 19 days of drug administration. 4. These data suggest that haloperidol administration does not alter the level of tyrosine hydroxylase or cholecystokinin mRNAs in midbrain dopamine neurons of the rat.
Cell Mol Neurobiol 1990 Mar
PMID:Tyrosine hydroxylase and cholecystokinin mRNA levels in the substantia nigra, ventral tegmental area, and locus ceruleus are unaffected by acute and chronic haloperidol administration. 197 Jul 57


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>