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)

The kappa B transcriptional enhancer motif, present in many viruses, is broadly active in many cell types. It is recognized by c-Rel/HIVEN86A in DNA affinity precipitation (DNAP) assays and by the Rel-related p50 and p65 subunits of the nuclear factor NF-kappa B in electrophoretic mobility shift assays (EMSA). We have analyzed activities that bind the human immunodeficiency virus type 1 and simian virus 40 kappa B motifs in two human leukemia cell lines, Jurkat and H9. In both DNAP and EMSA analyses of Jurkat cell extracts, we detected multiple kappa B motif-binding activities in addition to c-Rel/HIVEN86A and p50-p65 NF-kappa B. In Jurkat cell nuclear extracts, EMSA analysis revealed at least six specific DNA-protein complexes, of which one comigrated with the p50-p65 NF-kappa B complex. Formation of all six complexes was enhanced by stimulation of the cells with phorbol 12-myristate-13-acetate and phytohemagglutinin but was differentially affected by the salt concentration in the binding reaction and by the conditions of Jurkat cell growth. Nuclear extracts from both unstimulated and stimulated H9 cells revealed similar levels of five kappa B motif-specific complexes, all of which displayed mobilities distinct from those of the Jurkat cell complexes. Indeed, a complex corresponding to p50-p65 NF-kappa B was not detectable in nuclear extracts from unstimulated H9 cells although such a complex was apparent in nuclear extracts from stimulated H9 cells. In contrast to the inducibility of a p50-p65 NF-kappa B-like complex, transcriptional enhancers composed of multimerized kappa B motifs displayed similar high levels of activity in both the unstimulated and stimulated H9 cells. Thus, the activity of the kappa B motif in H9 cells corresponded to the abundance of the H9 cell-specific kappa B motif complexes and not to the levels of p50-p65 NF-kappa B complex. These results suggest that the broad activity of the kappa B enhancer element is not only due to the broadly distributed NF-kappa B activator but also to cell type-specific kappa B motif-binding activities.
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PMID:The kappa B enhancer motifs in human immunodeficiency virus type 1 and simian virus 40 recognize different binding activities in human Jurkat and H9 T cells: evidence for NF-kappa B-independent activation of the kappa B motif. 133 33

The cis-acting control elements of the interleukin-2 receptor alpha-chain (IL-2R alpha) gene contain a potent kappa B-like enhancer whose activity can be induced by various mitogenic stimuli. Recent cloning of the p50 and p65 subunits of the kappa B-binding protein NF-kappa B complex revealed a striking sequence homology of these proteins with the c-rel proto-oncogene product (c-Rel). On the basis of this homology, we examined the potential role of c-Rel in controlling IL-2R alpha transcription. We now demonstrate that the recombinant human c-Rel protein binds to the kappa B element in the IL-2R alpha promoter and results in alteration of the DNA structure in the adjacent downstream regulatory elements containing the CArG box and the GC box. We found that human c-Rel can activate transcription from the IL-2R alpha promoter, but not the kappa B-containing human immunodeficiency virus type 1 promoter, upon cotransfection into Jurkat T cells. Furthermore, truncation of the carboxyl terminus of c-Rel results in a c-Rel mutant (RelNA) that (i) localizes exclusively in the nucleus and (ii) acts in synergy with wild-type c-Rel in activating transcription from the kappa B site of the IL-2R alpha promoter. Finally, induction of surface IL-2R alpha expression coincides with the induced levels of endogenous c-Rel and induced c-Rel binding to the IL-2R alpha kappa B site. Our study identified c-Rel as one component of the Rel/NF-kappa B-family proteins involved in the kappa B-dependent activation of IL-2R alpha gene expression. Furthermore, our results suggest that a Re1NA-like cellular factor (e.g., NF-kappa B p50 or p49 subunit) acts in synergy with c-Re1 during T-cell activation.
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PMID:Kappa B site-dependent activation of the interleukin-2 receptor alpha-chain gene promoter by human c-Rel. 150 3

NF-kappa B is a protein complex which functions in concert with the tat-I gene product to stimulate human immunodeficiency virus (HIV) transcription. To determine whether specific members of the NF-kappa B family contribute to this effect, we have examined the abilities of different NF-kappa B subunits to act with Tat-I to stimulate transcription of HIV in Jurkat T-leukemia cells. We have found that the p49(100) DNA binding subunit, together with p65, can act in concert with Tat-I to stimulate the expression of HIV-CAT plasmid. Little effect was observed with 50-kDa forms of p105 NF-kappa B or rel, in combination with p65 or full-length c-rel, which do not stimulate the HIV enhancer in these cells. These findings suggest that the combination of p49(100) and p65 NF-kappa B can act in concert with the tat-I gene product to stimulate the synthesis of HIV RNA.
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PMID:Specific NF-kappa B subunits act in concert with Tat to stimulate human immunodeficiency virus type 1 transcription. 158 34

The v- and c-Rel oncoproteins bind to oligonucleotides containing kappa B motifs, form heterodimers with other members of the Rel family, and modulate expression of genes linked to kappa B motifs. Here, we report that the RxxRxRxxC motif conserved in all Rel/kappa B family proteins is absolutely required for v-Rel protein-DNA contact and its resulting transforming activity. We also demonstrate that serine substitution of the cysteine residue conserved within this motif enables v-Rel to escape redox control, thereby promoting overall DNA binding. These mutant proteins retained the ability to competitively inhibit kappa B-mediated transcriptional activation of the human immunodeficiency virus long terminal repeat but failed to efficiently transform chicken lymphoid cells both in vitro and in vivo. Our data indicate that reduction of the conserved cysteine residue in the RxxRxRxxC motif may be required for optimal DNA-protein interactions. These results provide direct biochemical evidence that the DNA-binding activity of v-Rel is subject to redox control and that the conserved cysteine residue in the RxxRxRxxC motif is critical for this regulation. These studies suggest that the DNA-binding, transcriptional, and biological activities of Rel family proteins may also be subject to redox control in vivo.
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PMID:The RxxRxRxxC motif conserved in all Rel/kappa B proteins is essential for the DNA-binding activity and redox regulation of the v-Rel oncoprotein. 162 Jan 18

The human immunodeficiency virus (HIV) enhancer element is important in the regulation of HIV gene expression. A number of cellular proteins have been demonstrated to bind to the NF-kappa B motifs in this element. The genes encoding several of these proteins, including members of the rel family and PRDII-BF1, have been cloned. We characterized the binding of proteins encoded by the human c-rel and PRDII-BF1 genes to HIV NF-kappa B motifs and related enhancer elements. Both the human c-rel protein and two proteins derived from the PRDII-BF1 gene by alternative splicing bound specifically to the HIV NF-kappa B motif and related enhancer elements found in the immunoglobulin kappa, class I major histocompatibility complex, and interleukin-2 receptor genes. To determine the role of these factors in regulating HIV gene expression, we fused the cDNAs encoding either of the two proteins derived by alternative splicing of the PRDII-BF1 gene or the c-rel gene to the DNA binding region of the yeast transcription factor GAL4. GAL4 binding sites were inserted in place of the native HIV enhancer sequences in an HIV long terminal repeat chloramphenicol acetyltransferase construct. Cotransfection of these constructs revealed that c-rel was a strong activator of basal HIV gene expression but did not result in synergistic effects in the presence of tat. PRDII-BF1-derived cDNAs did not result in stimulation of either basal or tat-induced activated gene expression. These results indicate that multiple enhancer binding proteins may potentially regulate HIV in both a positive and negative manner.
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PMID:Regulation of human immunodeficiency virus enhancer function by PRDII-BF1 and c-rel gene products. 172 88

Our studies originally demonstrated that the v-rel oncoprotein repressed gene expression in chicken lymphoid cells, while it activated transcription in rodent fibroblasts. Here we report that the c-rel protein can activate expression of genes linked to kappa B motifs when low levels of endogenous kappa B-binding activity are present. In contrast v-rel, and to a lesser extent c-rel, inhibit NF-kappa B-mediated activation of the human immunodeficiency virus long terminal repeat (HIV LTR) in phorbol ester-stimulated HeLa cells. Competition assays show that v-rel competitively inhibits both NF-kappa B and c-rel-mediated transcriptional activation. Analysis of mutant HIV LTR-chloramphenicol acetyltransferase (CAT) constructs in which all Sp1 or both NF-kappa B elements have been deleted shows that NF-kappa B motifs are required for rel-mediated effects on gene expression. Transforming v-rel mutants compete efficiently with phorbol ester-activated kappa B factors, whereas a transformation-defective mutant of v-rel is impaired in this activity. Taken together, these results strengthen the hypothesis that v-rel functions as a dominant interfering member of rel family proteins. These results also suggest that the ability of v- and c-rel to activate or repress gene expression in specific cells may result from their capacity to compete with endogenous rel family proteins whose expression and/or activity are cell-specific.
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PMID:Transcriptional activity of rel family proteins. 174 Nov 61

Although monocytic cells can provide a reservoir for viral production in vivo, their regulation of human immunodeficiency virus type 1 (HIV-1) transcription can be either latent, restricted, or productive. These differences in gene expression have not been molecularly defined. In THP-1 cells with restricted HIV expression, there is an absence of DNA-protein binding complex formation with the HIV-1 promoter-enhancer associated with markedly less viral RNA production. This absence of binding was localized to the NF-kappa B region of the HIV-1 enhancer; the 65-kDa plus 50-kDa NF-kappa B heterodimer was preferentially lost. Adding purified NF-kappa B protein to nuclear extracts from cells with restricted expression overcomes this lack of binding. In addition, treatment of these nuclear extracts with sodium deoxycholate restored their ability to form the heterodimer, suggesting the presence of an inhibitor of NF-kappa B activity. Furthermore, treatment of nuclear extracts from these cells that had restricted expression with lipopolysaccharide increased viral production and NF-kappa B activity. Antiserum specific for NF-kappa B binding proteins, but not c-rel-specific antiserum, disrupted heterodimer complex formation. Thus, both NF-kappa B-binding complexes are needed for optimal viral transcription. Binding of the 65-kDa plus 50-kDa heterodimer to the HIV-1 enhancer can be negatively regulated in monocytes, providing one mechanism restricting HIV-1 gene expression.
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PMID:Negative regulation of human immunodeficiency virus type 1 expression in monocytes: role of the 65-kDa plus 50-kDa NF-kappa B dimer. 194 56

Interleukin 12 (IL-12) is an inducible cytokine composed of 35- and 40-kDa subunits that is critical for promoting T helper type 1 development and cell-mediated immunity against pathogens. The 40-kDa subunit, expressed by activated macrophages and B cells, is induced by several pathogens in vivo and in vitro and is augmented or inhibited by gamma interferon (IFN-gamma) or IL-10, respectively. Control of IL-12 p40 expression is therefore important for understanding resistance and susceptibility to a variety of pathogens, including Leishmania major and perhaps human immunodeficiency virus. In this report, we provide the first characterization of IL-12 p40 gene regulation in macrophages. We localize inducible activity of the promoter to the sequence -122GGGGAATTTTA-132 not previously recognized to bind Rel family transcription factors. We demonstrate binding of this sequence to NF-kappa B (p50/p65 and p50/c-Rel) complexes in macrophages activated by several p40-inducing pathogens and provide functional data to support a role for NF-kappa B family members in IL-12 p40 activation. Finally, we find that IFN-gamma treatment of cells enhances this binding interaction, thus potentially providing a mechanism for IFN-gamma augmentation of IL-12 production by macrophages.
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PMID:Regulation of interleukin 12 p40 expression through an NF-kappa B half-site. 756 74

Vascular cell adhesion molecule 1 (VCAM-1) is expressed in both endothelial and epithelial cell types, where it contributes to lymphocyte migration to sites of inflammation. Its expression is regulated by cytokines, in part through two kappa B-like regulatory elements. Because NF-kappa B can be composed of multiple alternative subunits with differential effects on gene expression, the role of different specific NF-kappa B family members subunits in VCAM-1 regulation is unknown. In this report, we define the contribution of different NF-kappa B family members to VCAM-1 gene regulation. We show that both kappa B sites in the VCAM-1 enhancer are required to optimally stimulate gene expression, but the enhancer is differentially regulated by specific combinations of NF-kappa B subunits. At low concentrations, RelA(p65) acted in concert with the approximately 50-kDa product of p105 NF-kappa B, NF-kappa B1(p50), to stimulate transcription, and at high concentrations, RelA(p65) alone stimulated the VCAM-1 promoter. In contrast, NF-kappa B2 inhibited functional activation of the VCAM reporter by p65. Consistent with this finding, an additional binding complex was detected by using recombinant NF-kappa B2(p49)/RelA(p65) with radiolabeled VCAM kappa B site probes. Interestingly, the human immunodeficiency virus enhancer responded differently to stimulation by NF-kappa B subunits, with optimal response to p49(100)/p65. Analysis of NF-kappa B mRNA in human umbilical vein endothelial cells revealed that nfkb1, nfkb2, and relA NF-kappa B but not c-rel were induced by tumor necrosis factor alpha and lipopolysaccharide, which also induce VCAM-1. These data suggest that specific subunits of NF-kappa B regulate VCAM-1 and differentially activate other genes in these cells.
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PMID:Differential regulation of vascular cell adhesion molecule 1 gene expression by specific NF-kappa B subunits in endothelial and epithelial cells. 769 29

Distinct NF-kappa B subunit combinations contribute to the specificity of NF-kappa B-mediated transcriptional activation and to the induction of multiple cytokine genes including interferon-beta (IFN-beta). To evaluate the regulatory influence of different homo- and heterodimers, NF-kappa B subunits were analyzed for transcriptional activity in vitro using test templates containing two types of NF-kappa B recognition elements (the human immunodeficiency virus type 1 enhancer and the IFN-beta-positive regulatory domain-II (PRDII) as well as IFN-beta PRDIII-PRDI-PRDII linked to the -56 minimal promoter of rabbit beta-globin. Recombinant NF-kappa B subunits (p50, p65, c-Rel, p52, and I kappa B alpha) and interferon regulatory factor 1 were produced from either Escherichia coli or baculovirus expression systems. Transcriptional analysis in vitro demonstrated that 1) various dimeric complexes of NF-kappa B differentially stimulated transcription through the human immunodeficiency virus enhancer or PRDII up to 20-fold; 2) recombinant I kappa B alpha specifically inhibited NF-kappa B-dependent transcription in vitro; and 3) different NF-kappa B complexes and interferon regulatory factor 1 cooperated to stimulate transcription in vitro through the PRDIII-PRDI-PRDII virus-inducible regulatory domains of the IFN-beta promoter. These results demonstrate the role of NF-kappa B protein dimerization in differential transcriptional activation in vitro and emphasize the role of cooperativity between transcription factor families as an additional regulatory level to maintain transcriptional specificity.
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PMID:Differential transcriptional activation in vitro by NF-kappa B/Rel proteins. 785 94


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