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)

The present study examined the stress responsiveness of the hypothalamic-pituitary-adrenal axis in relation to the properties of corticosteroid receptors in the brain and pituitary in old (30 months) and young (3 months) male Brown Norway rats. The data demonstrate that circulating ACTH rather than the corticosteroid plasma level was elevated under basal conditions and following stress. Furthermore, a reduction of mineralocorticoid receptor (MR) number in the hippocampus and of glucocorticoid receptor (GR) number in the hypothalamus and the pituitary correspond to increased neuroendocrine responsiveness and negative feedback following stress. The changes in receptor binding do not parallel the changes in the amount of MR and GR mRNA measured with in situ hybridization. This suggests that the processing rather than the receptor gene expression is affected in senescence.
J Steroid Biochem Mol Biol 1991
PMID:Brain corticosteroid receptor gene expression and neuroendocrine dynamics during aging. 165 89

We have used okadaic acid (OA), a cell-permeable inhibitor of serine/threonine protein phosphatase types 1 (PP-1) and 2A (PP-2A), to demonstrate that the subcellular distribution of glucocorticoid receptor (GR) in rat fibroblasts is influenced by its phosphorylation state. Nuclear GRs in OA-treated cells retain transcriptional enhancement activity. Nuclear import or export of hormone agonist-bound GRs is not affected by OA. However, a dose of OA that fully inhibits PP-2A and partially inhibits PP-1, but not a lower dose that only partially inhibits PP-2A, leads to inefficient nuclear retention of agonist-bound GRs, and their redistribution into the cytoplasm. These receptors appear to be trapped in the cytoplasmic compartment and are unable to recycle (i.e. reenter the nucleus). Addition of OA during different steps of GR recycling demonstrates that OA must be present during nuclear export of GRs to block GR recycling. A direct role for PP-1 and/or PP-2A in GR recycling is suggested by site-specific hyperphosphorylation of GRs in vivo during OA inhibition of recycling. These are the same sites that undergo in vitro site-specific dephosphorylation by PP-1 and PP-2A. The block in GR recycling that results from inhibition of PP-1 and/or PP-2A resembles effects previously observed in v-mos-transformed rat fibroblasts. Interestingly, OA inhibition of PP-2A in v-mos-transformed cells leads to the reversal of oncoprotein effects on GR recycling and retention of receptors within the nuclear compartment. We propose that GR recycling is influenced by the activities of distinct protein phosphatases (PP-1 and/or PP-2A), and that the interference of this pathway observed in v-mos-transformed cells may be the result of effects of the oncoprotein on the phosphatases or a specific subset of their targets.
Mol Endocrinol 1991 Sep
PMID:Protein phosphatase types 1 and/or 2A regulate nucleocytoplasmic shuttling of glucocorticoid receptors. 166 12

The DNA binding domains of the nuclear receptor superfamily are highly conserved and consist of residues that fold into two zinc finger-like motifs, suggesting that the structures of this region among the members of the superfamily are likely to be very similar. Furthermore, the response elements that these receptors bind to are similar in sequence and organization. Nevertheless, these receptors selectively recognize target response elements and differentially regulate linked genes. In order to study the details of receptor:DNA binding, we have overexpressed and purified the vitamin D3 receptor DNA binding domain (VDRF) and have begun characterizing its DNA binding properties. We find that the VDRF protein binds strongly and specifically to direct repeats constituting a vitamin D response element from the mouse osteopontin (Spp-1) promoter region but weakly to the human osteocalcin vitamin D response element. Unlike receptors that recognize hormone response elements oriented as inverted repeats, such as the glucocorticoid receptor (GR) and estrogen receptor, VDRF appears to bind half-sites noncooperatively, without the free energy contribution of dimerization seen when the glucocorticoid receptor DNA binding domain associates with a glucocorticoid response element. By comparing and contrasting the DNA binding properties of the vitamin D and glucocorticoid receptors, we suggest a model for how receptors that prefer direct repeats differ in their binding strategy from those that recognize inverted repeats.
Mol Endocrinol 1991 Dec
PMID:DNA binding properties of the vitamin D3 receptor zinc finger region. 166 2

We demonstrate that the rat glucocorticoid receptor enhanced transcription in cultured Drosophila cells from Drosophila promoters linked to glucocorticoid response elements (GREs); promoters either containing or lacking a TATA box were rendered hormone inducible. Enhancement was dependent on the receptor, GREs, and the presence of an agonist ligand such as dexamethasone. The specific activities and relative efficacies of a series of potential ligands were generally similar in Drosophila and mammalian cells, except that dexamethasone mesylate, a potent antagonist in mammalian cells, was a strong agonist in Drosophila cells. A composite GRE, which mediates either positive or negative glucocorticoid regulation in animal cells depending on the presence and composition of the AP-1 transcription factor, conferred hormone-dependent enhancement, but not repression, in Drosophila cells. These results indicate that factors in addition to the receptor and GRE sequences participate as determinants of both signal transduction and transcriptional regulation by the glucocorticoid receptor, and that Drosophila cells carry functional homologs of many or all of those factors. Moreover, receptor activity can be exploited to obtain regulated gene expression in Drosophila.
Mol Endocrinol 1991 Jun
PMID:Signaling and regulation by a mammalian glucocorticoid receptor in Drosophila cells. 168 27

The mechanism of glucocorticoid resistance has been studied in a rat hepatoma cell variant (6.10.2), which contains low levels of glucocorticoid receptor (GR). These cells seem to have lost all the glucocorticoid-induced transcriptional responses as measured by the lack of induction of expression of stably integrated mouse mammary tumor virus (MMTV) and the endogenous gene tyrosine aminotransferase (TAT), as well as the transcriptional suppression of GR gene expression. Physico-chemical characterization of the GR in the glucocorticoid resistant 6.10.2 cells revealed that the receptor is indistinguishable from the wild-type receptor with regard to size, hormone- and DNA-binding. The levels of the receptor mRNA and the total immunoreactive protein found in 6.10.2 cells were about 20% of those found in wild-type cells. Further analysis of 6.10.2 cells demonstrated that the receptor was indeed biologically functional. Treatment of 6.10.2 cells with 8-bromo-cAMP, which induced the endogenous GR level two-fold, restored responsiveness to glucocorticoids. Secondly, pretreatment of the cells with cycloheximide also led to reacquisition of cellular responsiveness to glucocorticoids. We propose that there exists a "threshold" level of GR, which is required for responsiveness and that under normal culture conditions, the level of GR in 6.10.2 cells is below this threshold. Glucocorticoid responsiveness can be restored by raising the GR level above the threshold with 8-bromo-cAMP or, alternatively, by removing the threshold barrier (repressor protein) with cycloheximide. Finally, the existence of such a repressor protein for MMTV induction was shown by in vivo titration with an isolated negative cis-element from the MMTV promoter.
J Steroid Biochem Mol Biol 1991
PMID:The mechanism for glucocorticoid-resistance in a rat hepatoma cell variant that contains functional glucocorticoid receptor. 168 64

By means of double immunolabeling procedures it has been possible to demonstrate glucocorticoid receptor (GR) immunoreactivity (IR) in large numbers of various peptidergic neurons of the brain including neurons containing gastrointestinal peptides, opioid peptides, and peptides with a hypothalamic hormone function. For each peptide system, however, marked heterogeneities exist among brain regions. Thus, in the neocortex and the hippocampal formation most of the brain peptide neurons lack GR IR, while the same types of peptide neurons in the arcuate and paraventricular nucleus [e.g. neuropeptide Y (NPY), somatostatin (SRIF) and the cholecystokinin (CCK) neurons] possess strong GR IR. Furthermore, in the arcuate, parvocellular part of the paraventricular nuclei and the central amygdaloid nucleus practically all the peptidergic neurons are strongly GR IR, while in the lateral hypothalamus, mainly the neurotensin (NT) and galanin (GAL) IR neurons are GR IR. These marked differences among areas probably reflect functional differences dependent upon their participation in stress regulated circuits. All the paraventricular NT, corticotropin-releasing factor (CRF), growth hormone-releasing factor (GRF), thyrotropin-releasing hormone (TRH) and SRIF IR neurons appear to contain GR IR, while the luteinizing hormone-releasing hormone (LHRH) IR neurons lack GR IR, underlying the importance of glucocorticoids (GC) in controlling endocrine function. Finally, the GC may influence pain and mood control mainly via effects on enkephalin (ENK) neurons especially in the basal ganglia (mood) and on all beta-endorphin (beta-END) neurons of the arcuate nucleus, while most of the dynorphin neurons are not directly controlled by GC.
J Steroid Biochem Mol Biol 1991
PMID:Central peptidergic neurons as targets for glucocorticoid action. Evidence for the presence of glucocorticoid receptor immunoreactivity in various types of classes of peptidergic neurons. 168 65

The whey acidic protein (WAP) is a major milk protein. It is abundantly expressed in mammary epithelial cells, and its gene is controlled by lactogenic hormones. The identification of regulatory cis-acting sequences of the mouse WAP gene was so far dependent on the analysis of transgenic animals. We report here the possibility of analyzing regulatory sequences by gene transfer experiments using the lactogenic hormone-dependent mammary epithelial cell line HC11. A WAP-chloramphenicol acetyltransferase construct containing 2.5 kilobases of the 5'-flanking sequence of the WAP gene was stably transfected into HC11 cells. High chloramphenicol acetyltransferase activity was induced in pools of transfected cells cultured in the presence of the lactogenic hormones glucocorticoid, PRL, and insulin. A lower induction was observed by glucocorticoid hormone alone. PRL by itself was not able to induce the WAP gene promoter above the level observed in the absence of lactogenic hormones. A time course of hormone induction showed a weak initial response with a steady increase over at least 4 days of hormone treatment. Induction was not observable in the mammary epithelial cell line NOG-8 and NIH3T3 fibroblasts, despite the presence of functional glucocorticoid receptor in these cells. This indicates the requirement for a cell type-specific transcription factor present in the mammary epithelial cell line HC11, but not in NOG-8 epithelial cells or NIH3T3 fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1991 Nov
PMID:Lactogenic hormone and cell type-specific control of the whey acidic protein gene promoter in transfected mouse cells. 168 65

We have synthesized two peptides that correspond to unique regions of the amino-terminus of the human glucocorticoid receptor (GR). Peptides representing amino acids 245-259 and 346-367 (designated 59 and 57, respectively) were chosen on the basis of hydrophobicity/hydrophilicity ratios as well as overall proline content. These peptides were then used as antigens to produce epitope-specific antibodies that recognize and interact with human GR in a variety of physical states. Antiserum directed against each peptide recognizes denatured, [3H] dexamethasone mesylate-labeled GR as well as unliganded receptor on Western blots. In contrast to other antipeptide GR antibodies, these antibodies recognize and form stable complexes with unactivated and molybdate-stabilized forms of the GR, indicating that neither epitope is occluded when the receptor exists in an oligomeric state. Activated, 4S DNA-binding forms of the receptor are also recognized by both antibodies. The interaction of antibodies 59 and 57 with human GR in various states is highly specific based on the observation that preincubation of either antiserum with the appropriate peptide completely precludes the recognition of receptor by antibody. Titration analysis of antisera reveals that an increase in the antibody concentration cause discrete increases in the sedimentation coefficient of GR on sucrose gradients. These shifts occur under high salt conditions and are consistent with the formation of multiple stable antibody-receptor complexes. Interestingly, neither antibody interferes with the ability of the GR to be activated into a DNA-binding form or with the ability of the activated GR to interact with DNA cellulose. Consistent with these observations, both antibodies recognize and form stable complexes with GR when the receptor is associated with DNA fragments that contain specific glucocorticoid-responsive elements. Thus, both antibodies appear to recognize all known forms of the human GR protein. Using immunohistochemical techniques to visualize GR in HeLa S3 cells as well as in Chinese hamster ovary cells that stably express transfected human GR, a cytoplasmic location for receptor is observed in the absence of ligand. In contrast, immunoreactive GR is predominantly nuclear after hormone treatment, further supporting a role for nuclear translocation in GR function.
Mol Endocrinol 1990 Oct
PMID:Novel antipeptide antibodies to the human glucocorticoid receptor: recognition of multiple receptor forms in vitro and distinct localization of cytoplasmic and nuclear receptors. 170 80

The hepatic transcription of the angiotensinogen gene is regulated by both glucocorticoids and cytokines generated as products of the acute phase reaction. We have identified a multimodular enhancer in the 5'-flanking region of the rat angiotensinogen gene that mediates these responses and consists of an acute phase response element (APRE) flanked on both sides by adjacent glucocorticoid response element consensus motifs (GREs). Induction of transcription by the cytokine interleukin-1 (IL-1) is glucocorticoid dependent and mediated through the APRE. The APRE binds in a mutually exclusive manner a cytokine/phorbol ester-inducible protein (BPi), indistinguishable from nuclear factor kB, and a family of constitutive liver proteins (BPcs) related to the heat-stable transcription factor C/EBP. Using mutated 5'-flanking sequences of the angiotensinogen gene fused to a firefly luciferase reporter gene transfected into hepatoblastoma (HepG2) cells, we have mapped enhanson sequences required for the transcriptional response to glucocorticoids. Two functionally distinct GREs are identified by deletion and site-directed mutagenesis, both of which mediate glucocorticoid-stimulated transcription in vivo. Glucocorticoid-induced transcription mediated by the angiotensinogen gene enhancer is, furthermore, dependent on the occupancy of the APRE by either the BPi or a member of the BPc family because a mutant APRE that binds neither BPi nor BPc exhibits an attenuated glucocorticoid responsiveness. Mutant APREs that permit exclusive binding of either BPi or BPc synergistically transmit the glucocorticoid response mediated by one or the other of the adjacent GREs. Thus, the induction of angiotensinogen gene transcription involves interaction between the glucocorticoid receptor and either one of the APRE-binding proteins: either the cytokine-inducible NFkB or the constitutive family of C/EBP-like proteins, bound to adjacent enhansons in a mutually synergistic enhancer complex.
Mol Endocrinol 1990 Dec
PMID:Synergistic enhansons located within an acute phase responsive enhancer modulate glucocorticoid induction of angiotensinogen gene transcription. 170 27

Expression of the glycoprotein hormone alpha gene is regulated divergently by glucocorticoids in different cell types. Coexpression of the glucocorticoid receptor (GR) with an alpha-CAT reporter gene caused activation of alpha promoter activity in fibroblasts, but repression in JEG-3 choriocarcinoma cells, indicating that cell-specific factors dictate positive vs. negative regulation of this promoter by GR. Cell-specific sequences and other enhancer elements in the the alpha gene have been relatively well characterized in JEG-3 cells, and this model was used to further examine the mechanism of transcriptional repression by glucocorticoids. Promoter mutagenesis indicated that the degree of GR-mediated repression was impaired by a variety of deletional and site-directed mutations between -171 and -111 bp, a region that includes both cell-specific and cAMP response elements (CREs). In an attempt to further localize a negative glucocorticoid response element (GRE) sequence, binding studies were used to assess GR interactions with alpha promoter DNA sequences. Using avidin-biotin complex DNA binding assays, a series of overlapping alpha promoter DNA sequences between -170 to 29 basepairs were tested, but each failed to bind GR, whereas a control GRE avidly bound receptor. Similarly, in competition assays in transfected CV-1 cells, the alpha gene 5'-flanking sequence did not compete for GR stimulation of a glucocorticoid responsive reporter gene, whereas a sequence that contains known GR-binding sites (murine mammary tumor virus) effectively inhibited GR-mediated expression. The absence of high affinity GR-binding sites in the alpha promoter suggested that mutations that affected GR inhibition may have eliminated recognition sites for transactivators, which are themselves targets for the GR, rather than altering specific negative GRE sites in the DNA sequence. To examine this possibility, GR repression was studied using chimeric transcription factors. The transcription-activating domains of several different proteins (CREB, thyroid hormone receptor, or VP16) were linked to the DNA-binding domain of Gal-4, and transcription was driven by the Gal-4 recognition site (UAS). GR markedly repressed transactivation by Gal-4-CREB and, to a lesser degree, the Gal-4-thyroid hormone receptor and Gal-4-VP16 chimeric proteins. Repression occurred when UAS was linked to either the alpha promoter or to the E1B promoter. Thus, inhibition occurs in the absence of either the CRE or the proximal alpha promoter. These results support a mechanism in which GR-mediated repression in JEG-3 cells occurs by receptor interference with the transactivating potential of enhancer-binding proteins or associated transcription factors.
Mol Endocrinol 1991 Jan
PMID:Repression of the human glycoprotein hormone alpha-subunit gene by glucocorticoids: evidence for receptor interactions with limiting transcriptional activators. 170 98


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