Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Within the long terminal repeat (LTR) of the human immunodeficiency virus type 1 (HIV-1) provirus there exists a steroid hormone-responsive element corresponding to the TGTTCT sequence identified as the glucocorticoid receptor binding element within the LTR of mouse mammary tumor virus. We have used an LTR(HIV-1)-chloramphenicol acetyl transferase (CAT) plasmid construct to transfect infected H9V3 and noninfected H9 cells. Four hours before harvest the cells were divided into two parts and half was treated with hydrocortisone (10(-7) M). The cells were harvested and washed, and the CAT activity was measured. In eight repeat experiments an increased expression of the CAT gene has consistently been observed in H9V3 cells in response to the glucocorticoid but no significant effect of the steroid was observed in noninfected cells. Double transfection of LTR(HIV-1)-TAT and LTR(HIV-1)-CAT into noninfected H9 cells results in a cell population in which the CAT gene was responsive to glucocorticoid stimulation. A time course and dose response for the steroid effect have been determined and the binding of steroid receptor fo the LTR-DNA characterized by gel retardation experiments.
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PMID:Regulatory elements in the human immunodeficiency virus type 1 long terminal repeat LTR (HIV-1) responsive to steroid hormone stimulation. 831 48

The human immunodeficiency virus type 1 Rev protein controls expression of certain viral RNAs by binding to these RNAs in the nucleus. To investigate how dominant negative Rev mutants inhibit Rev function, we fused such mutants to hormone-dependent localization signals from the glucocorticoid receptor. Each was found to have fully potent inhibitory activity whether expressed in the nucleus or in the cytoplasm. Wild-type Rev colocalized with an inhibitory fusion protein, implying that the two proteins interact. The resulting complexes accumulated within nuclei in response to steroids but had no effect on expression of Rev-responsive mRNAs. A mutation known to block in vitro oligomerization of Rev abolished both complex formation and inhibitory activity of the mutant fusion proteins. Thus, trans-dominant inhibition of Rev does not require competition for nuclear substrates but may instead reflect the ability of a mutant to form nonfunctional complexes with the wild-type protein in vivo.
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PMID:trans-dominant inhibition of human immunodeficiency virus type 1 Rev occurs through formation of inactive protein complexes. 154 42

Previous reports (P. D. Katsanakis, C. E. Sekaris, and D. A. Spandidos, Anticancer Res. 11:381-383, 1991; J. Laurence, M. B. Sellers, and S. K. Sikder, Blood 74:291-297, 1989; R. Miksicek, A. Heber, W. Schmid, U. Danesch, G. Posseckert, M. Beato, and G. Schutz, Cell 46:283-290, 1986) have suggested the existence of a glucocorticoid response element in the long terminal repeat of human immunodeficiency virus (HIV) type 1. This study demonstrated a sequence-specific interaction of the glucocorticoid receptor DNA-binding domain with the previously predicted HIV glucocorticoid response element. This interaction may be relevant to the steroid responsiveness of HIV (P. A. Furth, H. Westphal, and L. Hennighausen, AIDS Res. Hum. Retroviruses 6:553-560, 1990; J. Laurence, M. B. Sellers, and S. K. Sikder, Blood 74:291-297, 1989; J. Laurence, H. Cooke, and S. K. Sikder, Blood 75:696-703, 1990; D. A. Spandidos, V. Zoounpovilis, A. Kotsinas, C. Tsiripotis, and C. E. Sekeris, Anticancer Res. 10:1241-1246, 1990).
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PMID:Glucocorticoid receptor-binding site in the human immunodeficiency virus long terminal repeat. 172 2

This study concerns 9 iv drug abusers with acquired immunodeficiency syndrome (AIDS) who developed hypercortisolism without the clinical signs or metabolic consequences of hypercortisolism. All patients were characterized by an Addisonian picture (weakness, weight loss, hypotension, hyponatremia, and intense mucocutaneous melanosis). An acquired form of peripheral resistance to glucocorticoids was suspected. We, therefore, examined glucocorticoid receptor characteristics on mononuclear leukocytes by measuring [3H]dexamethasone binding and the effect of dexamethasone on [3H]thymidine incorporation, which is one of the effects of glucocorticoid receptor activation. Glucocorticoid receptor density was increased in AIDS patients with an Addisonian picture (group 1; 16.2 +/- 9.4 fmol/million cells) compared to values in 12 AIDS patients without an Addisonian picture (group 2; 6.05 +/- 2.6 fmol/million cells; P less than 0.01) and sex- and age-matched controls (3.15 +/- 2.3 fmol/million cells; P less than 0.01). The affinity of glucocorticoid receptors (Kd) was strikingly decreased (9.36 +/- 3.44 nM in group 1; 3.2 +/- 1.5 nM in group 2; 2.0 +/- 0.8 nM in controls; P less than 0.01). [3H]Thymidine incorporation was decreased dose-dependently by dexamethasone in controls and patients; the effect was significantly blunted (P less than 0.05) in group 1 patients, which suggests that activation of glucocorticoid receptor is impaired as a result of the glucocorticoid receptor abnormality. In conclusion, AIDS patients with hypercortisolism and clinical features of peripheral resistance to glucocorticoids are characterized by abnormal glucocorticoid receptors on lymphocytes. Resistance to glucocorticoids implies a complex change in immune-endocrine function, which may be important in the course of immunodeficiency syndrome.
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PMID:Cortisol resistance in acquired immunodeficiency syndrome. 174 Apr 94

The human immunodeficiency virus type 1 (HIV-1) transactivator Rev is a nuclear protein that regulates expression of certain HIV-1 transcripts by binding to an RNA target element (the RRE) present in these transcripts. A short arginine-rich sequence in Rev contains the signals required to direct this protein into nuclei, where it associates preferentially with nucleoli. We created a steroid-inducible transactivator by fusing Rev with the steroid-binding domain of the glucocorticoid receptor (GR). This Rev/GR protein remains inactive in the cytoplasm when steroids are absent, but it enters the nucleus and initiates transactivation within minutes after exposure to dexamethasone. Although the GR moiety is sufficient to transport Rev/GR into nuclei, mutation of certain residues in the arginine-rich region blocks nucleolar localization and also inhibits transactivation. We find that other mutations in this region, however, can abolish the function of Rev/GR without affecting its localization; the latter phenotype may reflect a specific defect in binding of the RRE.
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PMID:Steroid-receptor fusion of the human immunodeficiency virus type 1 Rev transactivator: mapping cryptic functions of the arginine-rich motif. 221 12

An in vitro transcription system from mammary cells was established to study transcription of the long terminal repeat (LTR) of the mouse mammary tumor virus (MMTV). Experiments with progressive 5'-deletion constructs of the MMTV LTR revealed that a 19-base pair (bp) region from -41 to -23 bp, encompassing the TATA box and flanking DNA sequence, was as transcriptionally active as larger promoter constructs, both in nuclear extracts from human mammary cell lines (T47D and MCF7) and a nonmammary cell line (HeLa). The cell-free system was capable of supporting transcriptional induction by factors binding upstream of the TATA box, however, since purified glucocorticoid receptor-induced transcription in larger promoter constructs encompassing the MMTV hormone-responsive elements. Transcription from two other promoters, the adenovirus major late promoter and the human immunodeficiency virus LTR, also revealed a significant transcriptional contribution of upstream elements. The 19-bp TATA region from the MMTV LTR was shown to have considerably more activity in this transcription system than comparable TATA regions from other promoters. Sequences critical to the MMTV TATA region were evaluated by single base pair mutagenesis and found to comprise a consensus TATA box sequence, TATAAAA, as well as a single A just upstream of the TATAAAA sequence. Thus, the high level of basal transcription observed with the TATA region from MMTV is due to a perfect consensus TATA box sequence and a single base immediately 5' adjacent. It is likely that the high basal rate of transcription observed with this TATA box region on histone-free templates represents an inappropriate level of basal expression and that a complete evaluation of transactivation mechanisms in this system will require the recapitulation in vitro of the chromatin-mediated repressive state that exists in vivo.
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PMID:Role of the TATA box in transcription of the mouse mammary tumor virus long terminal repeat. 749 Nov 10

The vpr gene of human immunodeficiency virus type 1 (HIV-1) encodes a 15-kDa virion-associated protein that functions as a regulator of cellular processes linked to the HIV life cycle. We report the interaction of a 41-kDa cytosolic viral protein R interacting protein 1 (Rip-1) with Vpr in vitro. Rip-1 displays a wide tissue distribution, including relevant targets of HIV infection. Vpr protein induced nuclear translocation of Rip-1, as did glucocorticoid receptor (GR)-II-stimulating steroids. Importantly, Vpr and Rip-1 coimmunoprecipitated with the human GR as part of an activated receptor complex. Vpr complementation of a vpr mutant virus was also mimicked by GR-II-stimulating steroids. Vpr and GR-II actions were inhibited by mifepristone, a GR-II pathway inhibitor. Together these data directly link the activity of the vpr gene product to the glucocorticoid steroid pathway and provide a biochemical mechanism for the cellular and viral activity of Vpr, as well as suggest that a unique class of antivirals, which includes mifepristone (RU486), may influence HIV-1 replication.
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PMID:The glucocorticoid receptor type II complex is a target of the HIV-1 vpr gene product. 772 8

We examined the effect of chronic human immunodeficiency virus 1 (HIV-1) infection on the growth of human leukemic CEM T cells exposed to compounds which act through several major hormone or hormone-like signal transduction systems. Three were not altered by HIV-1 infection. Micromolar 8-bromo-cAMP inhibited cell growth equally in uninfected and infected cells. At the concentrations tested, neither (Bu)2cAMP nor the stimulator of protein kinase C, phorbol 12-myristate 13-acetate, altered the growth of infected or uninfected cells. The synthetic prostaglandin analog enisoprost also inhibited both equally. However, responses to two basic signal transduction systems, calcium uptake and the glucocorticoid pathway, were influenced by HIV infection. In chronically HIV-infected cells increased sensitivity to lysis by the calcium ionophore A23187 was observed. Additionally, the infected cells contained reduced amounts of glucocorticoid receptor sites and showed a statistically significant shift toward resistance to glucocorticoid-induced apoptosis.
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PMID:Interactions between human immunodeficiency virus infection and hormonal pathways: enhancement of calcium-induced but reduction of glucocorticoid-induced cell death. 839 9

Dexamethasone inhibited human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR)-directed gene expression in cells of T and B lymphoblastoid lineages, but not in monocytic cells. Suppression required an intact glucocorticoid receptor (GR), as it was amplified by transfection of lymphocytes with a plasmid encoding the human GR and blocked by the receptor antagonist RU486. These results were in direct contrast to the effects of dexamethasone on a murine leukemia retrovirus promoter where, consistent with the findings of others, activation of gene expression was obtained. Potential regions of the HIV-1 LTR mediating these effects were sought, with sequence homologies predicting two new glucocorticoid response element half-sites, GRE-II (nucleotides -6 to -1) and GRE-III (+ 15 to + 20), downstream from a previously identified GR DNA binding domain, GRE-I (-264 to -259). Mutational analyses documented the loss of inhibitory activity attendant on changes in GRE-III and the independence of steroid-mediated effects from GRE-I and GRE-II. Consistent with these findings, electrophoretic mobility shift assays revealed a difference in binding of cellular factors to GRE-III in cells of T and B lymphocyte vs. monocytic lineages. Binding sites for the cellular transcription factor leader binding protein (LBP-1) were found to overlap with GRE-III, and LBP-1 interacted with this element in the HIV LTR only in T and B lymphocytic extracts. We hypothesize that GRE-III sequence-specific effects, including modulation of LBP-GR interactions, underlie the negative regulatory effect of glucocorticoids on HIV-1 gene expression, with some specificity for cell type.
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PMID:Role of glucocorticoid receptor binding sites in the human immunodeficiency virus type 1 long terminal repeat in steroid-mediated suppression of HIV gene expression. 855 53

Fluid shear stress activates the expression of immediate early (IE) genes in vascular endothelial cells. The transcriptional regulation can be mediated through the shear stress-sensitive cis-acting elements at the 5' promoter regions of various IE genes such as the monocyte chemotactic protein-1 (MCP-1) gene. We linked wild-type and mutated MCP-1 promoters to the reporter gene luciferase and used such constructs to investigate the role of the phorbol ester TPA responsive element (TRE) in the shear-induced MCP-1 gene expression in vascular endothelial cells. Functional analysis showed that TGACTCC (a divergent TRE) located at nt -54 to -60 is necessary for shear-inducibility in bovine aortic endothelial cells (BAEC). The induction of the wild-type MCP-1 promoter construct by shear stress was attenuated by pretreating the cells with 1 microM dexamethasone or 1 microM retinoic acid 12 h before the shear stress experiments. The induction by shear stress reduced from 13-fold in the untreated cells to 7- and 3-folds in the dexamethasone- and retinoic acid-treated cells, respectively. These results demonstrate that the glucocorticoid receptor and retinoic acid receptor may interfere with the shear stress-activated AP-1/TRE. The reporter activity of HIV(LTR), which is a plasmid construct of the long terminal repeats of the human immunodeficiency virus and contains a kappa B enhancer element, was also activated by shear stress. The results of our investigations indicate that the shear stress-induced IE gene expression can be mediated through multiple cis-elements.
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PMID:Multiple cis-elements mediate shear stress-induced gene expression. 866 85


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