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

Hydrocortisone hemisuccinate within 4 hours after in vivo administration produced an increase in precursor incoporation into rat thymus RNA and proteins in the whole animal. From these results, together with information obtained from measurements of the tyrosine aminotransferase activity and the action of mitomycin C administered one hour before the injection of hydrocortisone, it can be concluded that the increase in tissue level of the enzyme, consequent to hydrocortisone treatment, results from an increased rate of biosynthesis of the enzyme, which participates in the catabolic processes of proteins in glucocorticoid sensitive thymus cells.
Mol Cell Biochem 1975 Dec 31
PMID:L-tyrosine: 2-oxoglutarate aminotransferase induction by hydrocortisone in the thymus of the white rat. 0 Jun 10

Sepharose 4B column with antibody to tyrosine aminotransferase (E.C. 2.6.1.5) (TAT) covalently bound can selectively remove a specific fraction of TAT polysomes from rat liver homogenates. From the polysomes which was adsorbed by immunosorbent one may obtain mRNA containing a segment of poly-adenilate-rich residues, having sedimentation constant of 11--16S. This mRNA may program synthesis of the specific protein in a cell free system. Near 70% of the protein was synthesized in such a system, may react with the antibody to TAT.
Mol Biol (Mosk)
PMID:Extraction of tyrosine aminotransferase mRNA by polyribosome immunosorption on sepharose 4B. 2 21

HTC cell variants chosen for their lack of tyrosine aminotransferase (EC 2.6.1.5) (TAT) induction by glucocorticoids were tested for interrelated effects on other glucocorticoid responses: TAT induction by dibutyryl cyclic AMP (dBcAMP) +/- dexamethasone, glutamine synthetase (GS) induction, cyclic nucleotide phosphodieterase (PDE) suppression, inhibition of alpha-aminoisobutyric acid (AIB) uptake, inhibition of plasminogen activator (PA), and induction of mouse mammary tumor virus (MTV). Loss of TAT induction by steroid was accompanied by loss of TAT induction by dBcAMP and of PDE suppression by steroid. In addition, subclones of MTV-infected cells were examined for the effect of the virus on glutamine synthetase (GS) and TAT induction. The virus had no effect on their induction in wild-type cells and no effect on GS induction in the variants. One MTV-infected subclone from a TAT variant, however, showed significant return of TAT induction.
Mol Cell Endocrinol 1979 Sep
PMID:Unlinked control of multiple glucocorticoid-induced processes in HTC cells. 3 58

The phosphoenolpyruvate carboxykinase (PEPCK) gene is highly expressed in cultured rat hepatoma cells, but extinguished in hepatoma x fibroblast hybrids. Extinction of PEPCK gene expression in hybrids is a polygenic process that involves several fibroblast loci, only one of which (tissue-specific extinguisher-1, TSE1) has been characterized to date. To identify sequence elements of the PEPCK gene that are involved both in TSE1-mediated extinction and in TSE1-independent processes, we assayed expression of chimeric PEPCK transgenes in transiently and stably transfected hybrid cells. We report that TSE1 responsiveness mapped to the PEPCK CRE (cAMP response element), as shown previously for the tyrosine aminotransferase gene. This was expected from the recent identification of the TSE1 gene product as a regulatory subunit of protein kinase A. However, none of the transgenes we assayed were responsive to TSE1-independent extinction mechanisms, suggesting that these controls require DNA sequences and/or chromatin structures that were not present in the transfected reporters. The implications of these findings are discussed.
Somat Cell Mol Genet 1992 Nov
PMID:Multiple elements regulate phosphoenolpyruvate carboxykinase gene expression in hepatoma hybrid cells. 133 26

The duration of the antagonizing activity of RU486 on tyrosine aminotransferase (TAT) induction and the glucocorticoid receptor in rat liver was studied. A single dose of RU486 (10 mg/kg) caused occupation of the cytosol glucocorticoid receptor in rat liver at 1 h. During this time no nuclear binding of [3H]dexamethasone ([3H]Dex) receptor complex was recorded, and TAT induction was completely blocked. TAT inducibility recovery parallelled receptor binding in both the cytosol and the nuclei, reaching maximum at 12 h. In contrast, nuclear binding recovered in 24 h, and [3H]Dex receptor binding in cytosol 48 h after RU486 application. It is concluded that the inhibitory effect of a single dose of RU486 on TAT induction is of rather short duration. At concomitant presence of agonist and antagonist in vivo, no direct correlation between agonist receptor occupancy and TAT induction could be observed.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Duration of antagonizing effect of RU486 on the agonist induction of tyrosine aminotransferase via glucocorticoid receptor. 134 26

The rat tyrosine aminotransferase gene (TAT) is a glucocorticoid-inducible gene, specifically expressed in liver. Using gel retardation assays, we have shown that its promoter (nt + 1 to -350; TAT.35) binds a combination of both ubiquitous and liver-specific trans-acting factors. Cis-acting sequences spanning: (i) nt -65 to -85 bound NF-Y, an ubiquitous "AACCAAT" box binding factor; (ii) nt -157 to -171 bound a liver-enriched member of the NF1 gene family [NF1Liver (NF1L hereafter)]; (iii) nt -266 to -281 bound the liver specific factor HNF1; and (iv) nt -283 to -288 bound ubiquitous "CCAAT" box binding factor(s). Moreover, the TAT gene promoter was able to drive liver-specific basal transcription, even in an in vitro assay using TAT-expressing (liver) vs non-expressing (spleen) crude nuclear extracts (NEs). Competition studies in transcription with both unmutated and mutated ds-oligonucleotides (ds-oligos) demonstrated that NF1L and HNF1 supported approx. 60 and 25% of the basal transcriptional activity sustained by TAT.35 in the liver, respectively. Neither of these oligos affected the very low level of transcription sustained by spleen NEs. This suggests a minor role for HNF1 in liver-specific basal TAT gene expression, consistent with previous observations with dedifferentiated C2 hepatoma cells (which does not express HNF1) [Deschatrette and Weiss. Biochimie 56 (1974) 1603-1611 and Cereghini et al. EMBO Jl9 (1990) 2257-2263]. Competition studies in liver-specific in vitro transcription with ds-oligo -265/-290 yielded a 90% inhibition, suggesting either that sequences spanning nt -283 to -288 sequester "CCAAT-box" binding factor(s) that may be relevant elsewhere for TAT promoter function (e.g. NF-Y which interacts with nt -65 to -85), or that such a factor interacts functionally with HNF1.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Two liver-enriched trans-acting factors support the tissue-specific basal transcription from the rat tyrosine aminotransferase promoter. 134 27

Tyrosine aminotransferase (L-tyrosine: 2 oxoglutarate aminotransferase; EC 2.6.1.5; TATase) is the first enzyme in the catabolic pathway of tyrosine. The gene of this transaminase is regulated by glucocorticoid hormones as well as via the cAMP pathway. This review gives a brief survey of the structural and physico-chemical properties of this well-known protein. A comparative study of the properties of TATase with other aminotransferases is also included to analyse this molecule for itself, and not only as a marker used in studies on enzymatic induction. Finally, the regulation of the gene expression is presented, in order to underline a few important features of this model.
Cell Mol Biol 1992 Apr
PMID:Tyrosine aminotransferase: a transaminase among others? 134 65

We have studied the requirement for an intact cAMP-dependent protein kinase (PKA) system to regulate cAMP-mediated gene transcription in Chinese hamster ovary (CHO) cells. Wild-type CHO cells and mutant CHO cell lines selected for their resistance to the growth inhibitory effect of 8-Br-cAMP and defective in their PKA system were transiently transfected with reporter plasmids containing 2.5 and 3.0 kb of the 5'-flanking sequence of the rat tyrosine aminotransferase (TAT) gene promoter. This segment of DNA contains no CRE-like sequences, yet wild-type transfectants exhibited a specific increase in TAT promoter activity following growth in medium containing 8-Br-cAMP. In CHO cell lines defective in their PKA, the transfected TAT promoter failed to respond to cAMP treatment. We conclude that an intact PKA system is necessary for the cAMP-mediated increase in TAT promoter activity in CHO cells and that there is no requirement for a CRE to see this effect.
Somat Cell Mol Genet 1992 Mar
PMID:Ablation of stimulation of a cAMP-responsive promoter in CHO cell lines defective in their cAMP-dependent protein kinase system. 134 45

Regulation of tyrosine aminotransferase (TAT) gene expression was examined in RALA255-10G, a simian virus-40 tsA mutant-immortalized adult rat hepatocyte line. At the nonpermissive temperature (40 C), these hepatocytes exhibited a differentiated phenotype and actively expressed the TAT gene, but only in the presence of dexamethasone (DEX). The glucocorticoid-mediated TAT expression was inhibited by cycloheximide, a protein synthesis inhibitor, and by RU486, a glucocorticoid antagonist, suggesting that glucocorticoid induction requires protein synthesis and may be mediated through hormone receptors. (Bu)2cAMP (Bt2cAMP) or retinoic acid, individually or in combination, failed to increase TAT mRNA levels. However, Bt2cAMP greatly potentiated the induction by DEX, whereas retinoic acid inhibited the induction by DEX or DEX/Bt2cAMP. Nuclear run-on assays demonstrated that the induction of TAT expression by DEX or DEX/Bt2cAMP in RALA255-10G cells is regulated primarily at the transcriptional level. In contrast, retinoic acid antagonized the DEX- or DEX/Bt2cAMP-mediated induction without affecting the rate of TAT gene transcription. Instead, retinoic acid destabilized TAT mRNA. The half-life values of TAT mRNA in DEX/Bt2cAMP- and DEX/Bt2cAMP/retinoic acid-treated cells were approximately 235-270 min and 90-100 min, respectively. Our results indicate that inhibition of TAT expression by retinoic acid was regulated primarily at the posttranscriptional level.
Mol Endocrinol 1992 Apr
PMID:Inhibition of tyrosine aminotransferase gene expression by retinoic acid. 135 56

The amount of agonist activity displayed by the antiglucocorticoid dexamethasone mesylate (Dex-Mes) for the induction of tyrosine aminotransferase (TAT) in rat hepatoma cells is greater than for glutamine synthetase and varies over a period of weeks. This variation, which has been reproduced over a period of 40 h by changing the density of the cells, suggests the involvement of a trans-acting factor. The target of this proposed trans-acting factor has now been localized to the region between -3.9 to -2.9 of the rat TAT gene from experiments with cells that were stably transfected with hybrid TAT/CAT constructs. Deletion experiments with transiently transfected TAT/tk promoter/CAT constructs revealed that this entire activity could be conveyed by a 21 bp sequence of the TAT gene. Gel shift experiments support the binding of a factor(s) to this 21 bp sequence. Thus the activity of the antagonist Dex-Mes is relatively independent of steroid structure and is largely determined by the further interactions of a trans-acting factor with the cis-acting sequence. We call this novel sequence a glucocorticoid modulatory element. A model is advanced which accounts for almost all of the results concerning TAT induction by glucocorticoids. This same model may also be useful in explaining why the amount of agonist activity of most antisteroids varies, even for different genes within the same cell.
J Steroid Biochem Mol Biol 1992 Sep
PMID:Modulation of the agonist activity of antisteroids by a novel cis-acting element. 135 17


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