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All immunoglobulin genes contain a conserved octanucleotide promoter element, ATGCAAAT, which has been shown to be required for their normal B-cell-specific transcription. Proteins that bind this octamer have been purified, and cDNAs encoding octamer-binding proteins have been cloned. Some of these proteins (referred to as OTF-2) are lymphoid specific, whereas at least one other, and We have identified two human pre-B-cell lines that contain extremely low levels of OTF-2 yet still express high levels of steady-state immunoglobulin heavy-chain mRNA in vivo and efficiently transcribe an immunoglobulin gene in vitro. Addition of a highly enriched preparation of OTF-1 made from one of these pre-B cells or from HeLa cells specifically stimulated in vitro transcription of an immunoglobulin gene. Furthermore, These results

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The IL-2 growth hormone is the major growth factor of activated T lymphocytes during a developing immune response. IL-2 is required not only for cell cycle progression but also to protect Ag-activated T cells from programmed cell death. In several cell types, activation of NF-kappa B and/or activating protein-1 (AP-1) has been demonstrated to be extremely important in blocking apoptosis. To determine The current study clearly demonstrates that IL-2 does Similarly, IL-2 On the other hand, the growth factor does induce the activation of STAT3 and STAT5 in these cells, as has been previously demonstrated. These data show that

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The expression of the gene encoding the granulocyte-macrophage colony-stimulating factor (GM-CSF) is induced upon activation of T cells with phytohemagglutinin and active phorbolester and upon expression of tax1, a transactivating protein of the human T-cell leukemia virus type I. The same agents induce transcription from the interleukin-2 receptor alpha-chain and interleukin-2 genes, depending on promoter elements that bind the inducible transcription factor NF-kappa B (or an NF-kappa B-like factor). We therefore tested the A recent functional analysis by Miyatake et al. (S. Miyatake, M. Seiki, M. Yoshida, and K. Arai, Mol. Cell. Biol. 8:5581-5587, 1988) described a short promoter region in the GM-CSF gene that conferred strong inducibility by T-cell-activating signals and tax1, but Using electrophoretic mobility shift assays, we showed binding of purified human NF-kappa B and of the NF-kappa B activated in Jurkat T cells to an oligonucleotide comprising the GM-CSF promoter element responsible for mediating responsiveness to T-cell-activating signals and tax1. As shown by a methylation interference analysis and oligonucleotide competition experiments, purified NF-kappa B binds at positions -82 to -91 (GGGAACTACC) of the GM-CSF promoter sequence with an affinity similar to that with which it binds to the biologically functional kappa B motif in the beta interferon promoter (GGGAAATTCC). Two kappa B-like motifs at positions -98 to -108 of the GM-CSF promoter were also recognized but with much lower affinities. Our data provide strong evidence that the expression of the GM-CSF gene following T-cell activation is controlled by binding of the NF-kappa B transcription factor to a high-affinity binding site in the GM-CSF promoter.

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Receptors for the Fc portion of immunoglobulin molecules (FcR) present on leukocyte cell membranes mediate a large number of cellular responses that are very important in host defense, including phagocytosis, cell cytotoxicity, production and secretion of inflammatory mediators, and modulation of the immune response. Cross-linking of FcR with immune complexes leads, first to activation of protein-tyrosine kinases. The molecular events that follow and that transduce signals from these receptors to the nucleus are still poorly defined. We have investigated the signal transduction pathway from Fc receptors that leads to gene activation and production of cytokines in monocytes. Cross-linking of FcR, on the THP-1 monocytic cell line, by immune complexes resulted in both activation of the transcription factor NF-kappaB and interleukin 1 production. These responses were completely blocked by tyrosine kinase inhibitors. In contrast, expression of dominant negative mutants of Ras and Raf-1, in these cells, did However, MAPK activation was easily detected by in vitro kinase assays, after FcR cross-linking with immune complexes. Using the specific MAPK/extracellular signal-regulated kinase kinase (MAPK kinase) inhibitor PD98059, we found that MAPK activation is necessary for FcR-dependent activation of the nuclear factor NF-kappaB. These results strongly

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Induction of the adaptive immune response depends on the expression of co-stimulatory molecules and cytokines by antigen-presenting cells. The mechanisms that control the initial induction of these signals upon infection are poorly understood. It has been proposed that their expression is controlled by the non-clonal, or innate, component of immunity that preceded in evolution the development of an adaptive immune system in vertebrates. We report here the cloning and characterization of a human homologue of the Drosophila toll protein (Toll) which has been shown to induce the innate immune response in adult Drosophila. Like Drosophila Toll, human Toll is a type I transmembrane protein with an extracellular domain consisting of a leucine-rich repeat (LRR) domain, and a cytoplasmic domain homologous to the cytoplasmic domain of the human interleukin (IL)-1 receptor. Both Drosophila Toll and the IL-1 receptor are known to signal through the NF-kappaB pathway. We show that a constitutively active mutant of human Toll transfected into human cell lines can induce the activation of NF-kappaB and the expression of NF-kappaB-controlled genes for the inflammatory cytokines IL-1, IL-6 and IL-8, as well as the expression of the co-stimulatory molecule B7.1, which is required for the activation of naive T cells.

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A long period of clinical latency before development of symptoms is characteristic of human immunodeficiency virus type 1 (HIV-1) infection. OM10.1, a promyelocyte cell line latently infected with HIV-1, has been developed as a model for studying the mechanism of viral latency and the activation of virus expression. We found that this latently infected cell line with heat shock at 42 degrees C for 2 h resulted in a high level of HIV-1 production The mechanism of activation was analyzed by using anti-TNF-alpha antibody and various inhibitors. Although the TNF-alpha level in culture supernatants was below the sensitivity of an ELISA assay system, addition of anti-TNF-alpha antibody in culture medium could partially suppress the heat shock induced HIV-1 production. Staurosporine (PKC inhibitor), pentoxifylline (NF-kappa B inhibitor), and Ro5-3335 (HIV-1 Tat inhibitor) also inhibited significantly the heat shock induced virus activation. In particular, staurosporine achieved approximately 90% inhibition of the HIV-1 antigen expression in heat shock-treated OM10.1 at a non-toxic concentration. Although Thus, the present observations will provide a further insight into the pathogenesis of HIV-1 infections.

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Optimal activation of T cells requires at least two signals. One signal can be delivered by the antigen-specific T-cell receptor, and the second signal is provided by the costimulatory molecule ( s ) delivered by the antigen-presenting cell. CD28 is a T-cell surface molecule and stimulation through this protein plays an important role in delivering the second activation signal. In this report, we show that in human peripheral blood T cells, CD28-mediated signal transduction involves the rel family proteins--c-Rel, p50, and p65. Treatment of peripheral blood T cells with phorbol 12-myristate 13-acetate (PMA) and anti-CD28 monoclonal antibody (mAb) results in augmentation of nuclear c-Rel, p50, and p65, and this augmentation can occur in the presence of the immunosuppressant cyclosporin A. It is also shown in this report that , in response to PMA/anti-CD28 mAb or anti-CD3/anti-CD28 mAb, c-Rel, p50, and p65 are associated with CD28-responsive element present in the promoter of the human interleukin 2 gene. The functional significance of c-Rel involvement in the CD28-responsive complex is demonstrated by transient transfection analysis, where cotransfection of c-Rel augments the level of expression of a chloramphenicol acetyltransferase reporter gene linked to the CD28-responsive element.

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Although transcriptional factors AP-1 and nuclear factor of activated T cells (NF-AT) are important for the normal induction of IL-2, it is unknown In the current studies, IL-2 production by T cells from elderly (mean 78 years) and young (mean 37 years) humans was measured in cultures stimulated with PHA, PHA plus PMA, crosslinked anti-CD3 mAB OKT3 plus PMA, or PMA plus ionomycin. Substantial decreases of IL-2 production were observed for cell cultures from 7 of 12 elderly individuals in response to the different stimuli, whereas the levels of IL-2 produced by stimulated T cells from other elderly individuals were equivalent to those observed for stimulated T cells of young subjects. Analyses of nuclear extracts by electrophoretic DNA mobility shift assays showed that decreased IL-2 production by stimulated T cells of elderly individuals was closely associated with impairments in the activation of both AP-1 and NF-AT. By contrast, T cells from elderly subjects with normal levels of IL-2 production exhibited normal activation of AP-1 and NF-AT. In addition, the results of competition experiments analyzing the normal components of NF-AT showed that the age-related reductions in stimulus-dependent NF-AT complexes corresponded to the slow migrating complexes that were composed of c-Fos/c-Jun AP-1. The resting and stimulated levels of NF kappa B were reduced in T cells from certain elderly individuals; however, alterations of NF kappa B did Thus, these results show that age-related impairments in the activation of AP-1 and NF-AT are closely associated with decreased expression of IL-2 and further

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Using homologous recombination, both EKLF alleles in murine embryonic stem (ES) cells were inactivated. These EKLF-/- ES cells were capable of undergoing in vitro differentiation to form definitive erythroid colonies that were similar in size and number to those formed by wild-type ES cells. However, the EKLF-/- colonies were poorly hemoglobinized and enucleated erythrocytes in these colonies contained numerous Heinz bodies. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses revealed that adult and embryonic globin genes were appropriately regulated, The ratio of adult beta-globin/alpha-globin mRNA in the mutant ES cells was 1/15 of that in wild-type ES cells. When the EKLF-/- cells were injected into blastocysts, they did In contrast, semiquantitative RT-PCR analysis of RNA from reticulocytes of the same chimeric animals This Consistent with this hypothesis, the short life span was ameliorated by introduction into the EKLF-/- ES cells of a human LCR/gamma-globin gene, as evidenced by the presence of ES cell-derived reticulocytes as well as mature erythrocytes in the blood of the chimeric animals.

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Flavonoids are a group of naturally-occurring phenolic compounds in the plant kingdom, and many flavonoids are found with vascular protective properties. Nevertheless how the protective response is exerted by flavonoids is not well characterized. In view of the nuclear factor-kappaB (NFkappaB) In this study, the effects of flavonoids on NFkappaB/inhibitor-kappaB (IkappaB) system in ECV304 cells activated with tumor necrosis factor-alpha (TNFalpha) were examined. We investigated the inhibitory action of six flavonoids on IkappaB kinase (IKK) activity, an enzyme recently found to phosphorylate critical serine residues of IkappaB for degradation. Of six flavonoids tested, myricetin was found to strongly inhibit IKK kinase activity, and prevent the degradation of IkappaBalpha and IkappaBbeta in activated endothelial cells. Furthermore, myricetin was also found to inhibit NFkappaB activity correlated with suppression of monocyte adhesion to ECV304 cells. Therefore we conclude that flavonoids Copyright 1999 Wiley-Liss, Inc.

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Transgenic mice with a lymphocyte-specific defect in NF-kappaB activation were produced by targeted expression of human IkappaB alpha. The thymic cellularity of these mice was significantly decreased. The proportion of mature, TCRhigh thymocytes of the alphabeta lineage was reduced, and the remaining TCRhigh population contained an unusually high proportion of double-positive cells. This defect in maturation resulted in a transgene dose-dependent reduction in peripheral T lymphocytes, with the CD8 lineage being more severely affected. These data provide direct evidence for the involvement of NF-kappaB/Rel family proteins in late stages of T lymphocyte development, coincident with positive and negative selection.

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Despite overwhelming evidence that enhanced production of the p75 tumor necrosis factor receptor (p75TNF-R) accompanies development of specific human inflammatory pathologies such as multi-organ failure during sepsis, inflammatory liver disease, pancreatitis, respiratory distress syndrome, or AIDS, the function of this receptor remains poorly defined in vivo. We show here that at levels relevant to human disease, production of the human p75TNF-R in transgenic mice results in a severe inflammatory syndrome involving mainly the pancreas, liver, kidney, and lung, and characterized by constitutively increased NF-kappaB activity in the peripheral blood mononuclear cell compartment. This process is shown to evolve independently of the presence of TNF, lymphotoxin alpha, or the p55TNF-R, although coexpression of a human TNF transgene accelerated pathology. These results establish an independent role for enhanced p75TNF-R production in the pathogenesis of inflammatory disease and implicate the direct involvement of this receptor in a wide range of human inflammatory pathologies.

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Thapsigargin (TG), an inhibitor of Ca(2+)-ATPase, depletes intracellular Ca2+ stores and induces a sustained Ca2+ influx TG plus phorbol myristate acetate (PMA) but However, TG induced increases in IL-2R alpha protein as well as IL-2R alpha mRNA in Jurkat T cells in a dose-dependent manner. A similar increase in IL-2R alpha by TG was also observed in human peripheral T cells. Further, like PMA, TG markedly induced NF kappa B in Jurkat T cells. However, TG and PMA exhibited a synergistic action on IL-2R alpha expression, PMA- but In toto, these results

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Nonhuman primates are naturally infected with a B-lymphotropic herpesvirus closely related to Epstein-Barr virus (EBV). These simian EBV share considerable genetic, biologic, and epidemiologic features with human EBV, including virus-induced tumorigenesis. However, latent, transformation-associated viral genes demonstrate marked sequence divergence among species despite the conserved functions. We have cloned the latent membrane protein 1 (LMP1) homologs from the simian EBV naturally infecting baboons (cercopithicine herpesvirus 12, herpesvirus papio) and rhesus monkeys (cercopithicine herpesvirus 15) for a comparative study with the human EBV oncogene. The transmembrane domains are well conserved, but there is striking sequence divergence of the carboxy-terminal cytoplasmic domain essential for B-cell immortalization and interaction with the tumor necrosis factor receptor signaling pathway. Nevertheless, the simian EBV LMP1s retain most functions in common with EBV LMP1, including the ability to induce NF-(kappa)B activity in human cells, to bind the tumor necrosis factor-associated factor 3 (TRAF3) in vitro, and to induce expression of tumor necrosis factor-responsive genes, such as ICAM1, in human B lymphocytes. Multiple TRAF3 binding sites containing a PXQXT/S core sequence can be identified in the simian EBV LMP1s by an in vitro binding assay. A PXQXT/S-containing sequence is also present in the cytoplasmic domain of the Hodgkin 's disease marker, CD30, and binds TRAF3 in vitro. The last 13 amino acids containing a PXQXT/S sequence are highly conserved in human and simian EBV LMP1 but do The conserved TRAF3 binding sites in LMP1 and the CD30 Hodgkin 's disease marker provides further evidence that a TRAF3-mediated signal transduction pathway

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Acute promyelocytic leukemia (APL) is a specific type of acute myeloid leukemia characterized by the morphology of the blast cells, a specific t(15;17) translocation, and risks of definite coagulopathy. Recently this leukemia was further characterized by an exquisite sensitivity to all-trans retinoic acid 's differentiation effect and the production of a fusion gene altering the gene of RARalpha and a novel gene PML. In vivo differentiation therapy with retinoids in APL patients follows strict guidelines related both to the APL cell and the biodisposal of all-trans retinoic acid.

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Interleukin-8 (IL-8) is a chemokine that belongs to the alpha-chemokine or CXC subfamily and is produced by a wide variety of human cells, including monocytes and polymorphonuclear cells (PMN). IL-8 is secreted in response to inflammatory stimuli, notably bacterial products such as lipopolysaccharide (LPS), but little is known about the mechanisms by which these agents mediate IL-8 induction. In this report, we show that Mycoplasma fermentans lipid-associated membrane proteins (LAMPf) induce the production of high levels of IL-8 by THP-1 (human monocyte) cells and PMN at the same extent as LPS. It was previously demonstrated that stimulation of monocytic cells with either LPS or LAMPf led to a series of common downstream signaling events, including the activation of protein tyrosine kinase and of mitogen-activated protein kinase cascades. By using PD-98059 and SB203580, two potent and selective inhibitors of MEK1 (a kinase upstream of ERK1/2) and p38, respectively, we have demonstrated that both ERK1/2 and p38 cascades play a key role in the production of IL-8 by monocytes and PMN stimulated with bacterial fractions.

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The transcriptional regulatory elements of many inducible T-cell genes contain adjacent or overlapping binding sites for the Ets and NF-kappaB/NFAT families of transcription factors. Similar arrays of functionally important NF-kappaB/NFAT and Ets binding sites are present in the transcriptional enhancers of human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2), Despite these findings, In the studies described in this report, we demonstrated a physical interaction between multiple Ets and NF-kappaB/NFAT proteins both in vitro and in activated normal human T cells. This interaction is mediated by the Ets domain of Ets proteins and the C-terminal region of the Rel homology domains of NF-kappaB/NFAT proteins. In addition, the Ets-NF-kappaB/NFAT interaction requires the presence of DNA binding sites for both proteins, as it is abolished by the DNA intercalating agents propidium iodide and ethidium bromide and enhanced by the presence of synthetic oligonucleotides containing binding sites for Ets and NF-kappaB proteins. A dominant-negative mutant of NF-kappaB p50 that binds DNA but Taken together, these findings These interactions represent a

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Activation of cytoplasmic tyrosine kinases is an important aspect of signal transduction mediated by integrins. In the human monocytic cell line THP-1, either integrin-dependent cell adhesion to fibronectin or ligation of beta 1 integrins with antibodies causes a rapid and intense tyrosine phosphorylation of two sets of proteins of about 65-75 and 120-125 kDa. In addition, integrin ligation leads to nuclear translocation of the p50 and p65 subunits of the NF-kappa B transcription factor, to activation of a reporter gene driven by a promoter containing NF-kappa B sites, and to increased levels of mRNAs for immediate-early genes, including the cytokine interleukin (IL)-1 beta. The tyrosine kinase inhibitors genistein and herbimycin A block both integrin-mediated tyrosine phosphorylation and increases in IL-1 beta message levels, indicating a causal relationship between the two events. The components tyrosine phosphorylated subsequent to cell adhesion include paxillin, pp125FAK, and the SH2 domain containing tyrosine kinase Syk. In contrast, integrin ligation with antibodies induces tyrosine phosphorylation of Syk but In adhering cells, pre-treatment with cytochalasin D suppresses tyrosine phosphorylation of FAK and paxillin but These observations

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A theoretical pathway of transcriptional regulation of the androgen receptor (AR) gene is via a cAMP response element (CRE) present in its promoter region (-508 to -501). After 20 h of stimulation with 8-bromo-cAMP, AR mRNA was upregulated in LNCaP but We have demonstrated that the level of CRE binding protein (CREB) was the same in all cell lines and that the The ability to regulate AR gene transcription via the second messenger pathway is lost in the PC-3 and DU-145 cell lines. This

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For the study of the changes in plasma interleukin-1 (IL-1) and their The activity of IL-1 was expressed as its ability to stimulate 3H-TdR incorporation in the thymocytes of C57 mice. GR was determined by whole cell assay with 3H-Dex. The results showed that the activity of plasma IL-1 in aged long-distance runner was 209 %, 223 % and 145 % of the control at 14.7-18.7, 3.8-7.0 and 1.5-2.6 KD fractions. The GR in peripheral blood leukocytes in aged runner was 65 % of the control.

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The transcription of the human immunodeficiency virus type 1 (HIV-1) is under the control of cellular proteins that bind to the viral long terminal repeat (LTR). Among the protein-binding regions of the HIV-1 LTR is the transcription-enhancer region. We show that at least one inducible, C1, and one constitutive, C2, protein can bind to the HIV enhancer in Jurkat cells. The two proteins differ in their surface charge, since they are separable by anion-exchange chromatography. Bivalent cations such as Mg2+ and Zn2+ differentially affect their binding to oligonucleotides which contain the HIV-enhancer domain. Both C1 and C2 proteins also bind to a similar sequence found in the interleukin-2-receptor alpha-subunit enhancer. The inducible C1 protein was partially purified by three chromatographic steps and characterized by u.v. cross-linking as a 47 kDa protein.

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The human platelet-activating factor receptor (PAFR) gene is transcribed by two distinct promoters (promoter 1 and promoter 2) to generate two transcripts (designated as PAFR transcript 1 and PAFR transcript 2), though their open reading frames are identical. By primer extension analysis to discriminate two transcripts, we found that the levels of PAFR transcript 1 (leukocyte-type), but Functional analysis of the promoter 1 with a transient expression assay using chloramphenicol acetyltransferase (CAT) gene as a reporter showed that both PAF and TPA activated the promoter 1 but These findings

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The class II trans- activator (CIITA) is the main transcriptional co-activator for the expression of MHC class II proteins. Its N-terminal 125 amino acids function as an independent transcriptional activation domain. Analyses of the primary amino acid sequence of the activation domain predict the presence of three alpha-helices, each with a high proportion of acidic residues. Using site-directed mutagenesis, we found that two of these predicted alpha-helices are required for full transcriptional activation by CIITA. Moreover, a CIITA protein in which both functional alpha-helices have been deleted displays a dominant negative phenotype. This activation domain of CIITA interacts with the 32 kDa subunit of the general transcription complex TFIID, TAFII32. Decreased transcriptional activation by N-terminal deletions of CIITA is correlated directly with their reduced binding to TAFII32. We conclude that interactions between TAFII32 and CIITA are responsible for activation of class II genes.

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Human monocytes isolated from peripheral blood of healthy donors show a time-dependent differentiation into macrophages upon in vitro cultivation, closely mimicking their in vivo migration and maturation into extravascular tissues. We investigated the involvement of signal transducers and activators of transcription (STAT) factors in this phenomenon and reported the specific, time-dependent, activation of STAT1 protein starting at day 0/1 of cultivation and maximally expressed at day 5. STAT1 activity was evident on the STAT binding sequences (SBE) present in the promoters of genes which are up-regulated during monocyte to macrophage maturation such as FcgammaRI and ICAM-1, and in the promoter of the transcription factor IFN regulatory factor-1. Moreover, the effect of cell adhesion to fibronectin or laminin was studied to investigate mechanisms involved in STAT1 activation. Compared with monocytes adherent on plastic surfaces, freshly isolated cells allowed to adhere either to fibronectin- or laminin-coated flasks exhibited an increased STAT1 binding activity both in control and in IFN-gamma-treated cells. The molecular events leading to enhanced STAT1 activation and cytokine responsiveness concerned both Y701 and S727 STAT1 phosphorylation. Exogenous addition of transforming growth factor-beta, which exerts an inhibitory effect on some monocytic differentiation markers, inhibited macrophage maturation, integrin expression and STAT1 binding activity. Taken together these results

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Malignant transformation usually inhibits terminal cell differentiation but PU.1 is a hematopoietic-specific Ets family transcription factor that is required for development of some lymphoid and myeloid lineages. PU.1 can also act as an oncoprotein as activation of its expression in erythroid precursors by proviral insertion or transgenesis causes erythroleukemias in mice. Restoration of terminal differentiation in the mouse erythroleukemia (MEL) cells requires a decline in the level of PU.1, Here we investigate the mechanism by which PU.1 interferes with erythroid differentiation. We find that PU.1 interacts directly with GATA-1, a zinc finger transcription factor required for erythroid differentiation. Interaction between PU.1 and GATA-1 requires intact DNA-binding domains in both proteins. PU.1 represses GATA-1-mediated transcriptional activation. Both the DNA binding and transactivation domains of PU.1 are required for repression and both domains are also needed to block terminal differentiation in MEL cells. We also show that ectopic expression of PU.1 in Xenopus embryos is sufficient to block erythropoiesis during normal development. Furthermore, introduction of exogenous GATA-1 in both MEL cells and Xenopus embryos and explants relieves the block to erythroid differentiation imposed by PU.1. Our results

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BACKGROUND: A delicate balance between positive and negative regulatory mechanisms during T-cell activation determines the specificity and magnitude of an immune response. Phosphoinositide 3-kinase (PI 3-kinase) is activated by a diverse set of receptors that determine T-cell function, including the T-cell antigen receptor (TCR), the costimulatory receptor CD28, and negative regulators of T-cell activation such as CTLA-4. PI 3-kinase is also regulated by the haematopoietic cytokines that determine T-cell differentiation and lymphocyte proliferation. PI 3-kinase can thus dynamically influence the outcome of the immune reactions at various stages. In this study, we investigated the importance of PI 3-kinase in TCR-directed T-cell activation using activated or inhibitory versions of PI 3-kinase. RESULTS: We found, however, that PI 3-kinase profoundly influenced the transactivation capacity of 'nuclear factor of activated T cells' (NF-AT) elicited by the TCR: expression of an activated form of PI 3-kinase inhibited TCR-mediated NF-AT responses, whereas expression of a dominant negative mutant of PI 3-kinase potently enhanced TCR-controlled NF-AT induction. CONCLUSIONS: Our results establish that PI 3-kinase can both positively and negatively regulate T-cell function, and uncover a previously unrecognized function for PI 3-kinase in T cells as a selective negative regulator of TCR-signalling events and therefore as a determinant of T-cell homeostasis.

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Activated neutrophils have the ability to upregulate the expression of many genes, in particular those encoding cytokines and chemokines, and to subsequently release the corresponding proteins. Although little is known to date concerning the regulation of gene transcription in neutrophils, it is noteworthy that many of these genes depend on the activation of transcription factors, such as NF-kappaB, for inducible expression. We therefore investigated We now report that dimers consisting of p50 NFkappaB1, p65 RelA, and/or c-Rel are present in neutrophils and that the greater part of these protein complexes is physically associated with cytoplasmic IkappaB-alpha in resting cells. Following neutrophil stimulation with proinflammatory agonists (such as lipopolysaccharide [LPS], tumor necrosis factor-alpha [TNF-alpha], and fMet-Leu-Phe) that induce the production of cytokines and chemokines in these cells, NF-kappaB/Rel proteins translocated to nuclear fractions, resulting in a transient induction of NF-kappaB DNA binding activity, as determined in gel mobility shift assays. The onset of both processes was found to be closely paralleled by, and dependent on, IkappaB-alpha degradation. Proinflammatory neutrophil stimuli also promoted the accumulation of IkappaB-alpha mRNA transcripts, resulting in the reexpression of the IkappaB-alpha protein. To our knowledge, this constitutes the first

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Several studies have pointed to a link between immune and endocrine systems, including a regulatory function of GH on monocyte activation. The present study demonstrates that human THP-1 promonocytic cells, engineered by gene transfer to constitutively produce human growth hormone (hGH), secreted depressed amounts of TNF-alpha in response to challenge by LPS. The GH-induced inhibitory effect was also observed using normal human monocytes and monocyte-derived macrophages. Inhibition of TNF-alpha production by THP-1-hGH-transfected cells cultured in the presence of LPS is dependent on a selective pathway, since Inhibition of TNF-alpha secretion by LPS-stimulated THP-1-hGH cells was associated with a decrease in nuclear translocation of nuclear factor-kappaB. The capacity of GH to inhibit LPS-induced TNF-alpha production by monocytes

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Lytic transition of Epstein-Barr virus (EBV) is initiated by distinct immediate early regulators of the viral cycle, in synchronization to temporary, permissive conditions during host cell differentiation. We developed eukaryotic vectors suitable to imitate the processes involved in lytic transition in cell culture systems. Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1 trans-activator (Zta). R7-57 reporter cells, on the other hand, signaled induced activity of the lytic origin of EBV replication (ori Lyt). Different modes, like chemical induction, lytic superinfection with EBV and single gene trans-activation converted the recombinant ori Lyt element in R7-57 reporter cells. BZLF 1, transiently expressed in R7-57 reporter cells, was the only EBV trans-activator found, sufficient in inducing the viral lytic cycle. Basing on these experiments, trans-cellular activation of EBV was tested by cocultivation of BZLF 1-expressing R59Z activator cells with the R7-57 reporter line. Latency breaking activity, however, was transferred from activator to reporter cells when active, exogenous virus was added. The cell system described in these experiments provides a tool for the detection of EBV reactivation and demonstrates the potential of the lytic regulatory gene BZLF 1.

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The coordinated production of all blood cells from a common stem cell is a highly regulated process involving successive stages of commitment and differentiation. From analyses of mice deficient in transcription factor genes and from the characterizations of chromosome breakpoints in human leukemias, it has become evident that transcription factors are important regulators of hematopoiesis. During myelopoiesis, which includes the development of granulocytic and monocytic lineages, transcription factors from several families are active, including AML1/CBF beta, C/EBP, Ets, c-Myb, HOX, and MZF-1. Few of these factors are expressed exclusively in myeloid cells; instead it Here we discuss recent advances in transcriptional regulation during myelopoiesis.

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M-TAT is a cytokine-dependent cell line with the potential to differentiate along the erythroid and megakaryocytic lineages. We cultured M-TAT cells long term (> 1 year) in the continuous presence of erythropoietin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF), or stem cell factor (SCF). These long term cultures are referred to as M-TAT/EPO, M-TAT/GM-CSF, and M-TAT/SCF cells, respectively. Hemoglobin concentration and gamma-globin and erythroid delta-aminolevulinate synthase mRNA levels were significantly higher in M-TAT/EPO cells than in M-TAT/GM-CSF cells. When the supplemented cytokine was switched from GM-CSF to EPO, hemoglobin synthesis in M-TAT/GM-CSF cells increased rapidly (within 5 h), and the level of GATA-1 mRNA increased. In contrast, the addition of GM-CSF to the M-TAT/EPO cell culture decreased the amount of hemoglobin, even in the presence of EPO, Thus, erythroid development of M-TAT cells is promoted by EPO and suppressed by GM-CSF. These results support the

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We tested the effect of three linear or two loop peptides derived from the V3 region of the HTLV-III BH10 clone or the SF2 strain of human immunodeficiency virus type 1 on IL-2-driven T cell proliferation. V3-BH10, which consists of 42 amino acids and has a loop structure, suppressed IL-2-driven proliferation of all IL-2-dependent cells [Kit225, ED-40515(+), KT-3, 7-day PHA-blasts, and fresh peripheral blood mononuclear cells] tested, whereas it did This suppressive effect was also seen in IL-2-driven cell growth of CD8-positive lymphocytes purified from 7-day PHA-blasts, The treatment with anti-V3 loop monoclonal antibody (902 antibody) completely abolished the suppressive effect of V3-BH10. In addition, V3-BH10 generated the arrest of Kit225 cells and also purified CD8-positive lymphocytes in G1 phase in the presence of IL-2. V3-BH10 However, V3-BH10 enhanced IL-2-induced mRNA expression of c-fos but Thus,

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In previous studies, it was shown that the fusion region of the pml/RAR-alpha protein, expressed by acute promyelocytic leukemia (APL) cells, can be specifically recognized in vitro by donor (D. E.) CD4 T cells in a HLA class II DR11-restricted fashion. We present here the results on the recognition of several pml/RAR-alpha peptides by APL patients expressing HLA DR11. The in vitro immunization of peripheral blood lymphocytes from four patients in remission (S.R., F.R., M.M., P. G.) with BCR1/25, a 25-mer pml/RAR-alpha, did We then generated new donor anti-pml/RAR-alpha CD4(+) T-cell clones. These clones were tested for their recognition of BCR1/25. One clone (C3/5, CD3(+), CD4(+), CD8(-)) was selected for further analysis. Clone C3/5 showed specific proliferation, cytotoxicity, and cytokine (tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor) production when challenged with autologous lymphoblastic cell lines pulsed with peptide BCR1/25. C3/5 cells developed specific proliferation and cytotoxicity when challenged with peptide-pulsed lymphoblastic cell lines and peripheral blood lymphocytes from the four DR11(+) APL patients. Incubation of APL cells with IFN-gamma Since APL cells do These findings are discussed in relation to

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MNDA (myeloid cell nuclear differentiation antigen) is an interferon alpha regulated nuclear protein expressed only in cells of the human myelomonocytic lineage. To identify mechanisms responsible for this lineage-specific and interferon-regulated expression, the 5' flanking sequence of the gene has been characterized. Two interferon-stimulated response elements (ISRE) flank a multiple transcription start site region identifying MNDA as a TATA-less interferon-regulated gene. Other DNA elements present include a cluster of Myb sites, several Ets, an Ets related PU.1 site and an Sp1 site located within 600 bp of the transcription start sites. In addition, DNA methylation was revealed as one of the The 5' flanking sequence has promoter activity which is elevated by interferon alpha. The findings

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The role of cellular redox status in both cytotoxic activity and NF-kappa B activation in natural killer (NK) cells was investigated. The results Pretreatment of NK cells with the antioxidant pyrrolidine dithiocarbarmate (PDTC) leads to the inhibition of NF-kappa B activation but the AP-1 binding to DNA was superinduced. The inhibition of NF-kappa B by PDTC paralleled with an inhibition of spontaneous cytotoxicity mediated by NK cells. Moreover, the inhibitors of serine proteases, N-alpha-tosyl-L-lysine chloromethyl ketone and N-alpha-tosyl-L-phenylalanine chloromethyl ketone, also blocked the cytolytic activity of NK cells against the sensitive target K562. In contrast, Altogether, these results support the

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Previous cotransfection experiments had demonstrated that ectopic expression of the lymphocyte-specific transcription factor Oct2 Oct2 expression was We have tested a variety of Oct2 isoforms generated by alternative splicing for the capability to activate an octamer enhancer in nonlymphoid cells and a B-cell line. Our analyses show that several Oct2 isoforms can stimulate from a remote position but that this stimulation is restricted to B cells. This result Mutational analyses Moreover, this domain conferred enhancing activity when fused to the Oct1 protein, which by itself was The glutamine-rich activation domain present in the amino-terminal portion of Oct2 and the POU domain contribute only marginally to the transactivation function from a distal position.

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Deactivation of mononuclear phagocytes is critical to limit the inflammatory response but We compared the effects of the deactivating cytokine interleukin 10 (IL-10) on human peripheral blood mononuclear cell (PBMC) responses to lipopolysaccharide (LPS), Cryptococcus neoformans, and Candida albicans. IL-10 effected dose-dependent inhibition of tumor necrosis factor alpha (TNF-alpha) release in PBMC stimulated by LPS and C. neoformans, with significant inhibition seen with 0.1 U/ml and greater than 90% inhibition noted with 10 U/ml. In contrast, even at doses as high as 100 U/ml, IL-10 inhibited TNF-alpha release in response to C. albicans by only 50%. IL-10 profoundly inhibited release of IL-1beta from PBMC stimulated by all three stimuli. TNF-alpha mRNA and release was inhibited even if IL-10 was added up to 8 h after cryptococcal stimulation. In contrast, inhibition of IL-1 beta mRNA was of lesser magnitude and occurred only when IL-10 was added within 2 h of cryptococcal stimulation. IL-10 inhibited translocation of NF-kappaB in response to LPS but All three stimuli induced IL-10 production in PBMC, although over 10-fold less IL-10 was released in response to C. neoformans compared with LPS and C. albicans. Thus, while IL-10 has deactivating effects on PBMC responses to all three stimuli, disparate stimulus- and response-specific patterns of deactivation are seen.

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BACKGROUND . The proliferative activity of tumors has been extensively investigated with different approaches, among which the use of the monoclonal antibody Ki-67 represents an easy and reliable means of assessing cell proliferation. In this study, the proliferative activity of 129 primary breast cancers was investigated, and the results were related to prognosis. METHODS . Tumor samples, obtained from 129 patients who underwent surgery between January 1987 and December 1988, were processed for staining by an immunohistochemical procedure (avidin-biotin complex). The median time of observation was 42 months (range, 31-55 months). Life-table analysis (Mantel-Cox) was used to assess the probability of disease-free survival (DFS) and overall survival (OS). RESULTS . Tumors with high Ki-67 proliferation indices (> 20%) were associated with a higher 4-year probability of relapse of disease (55.3 % versus 79.1 %; P = 0.003) and death (71 % versus 95.6 %; P = 0.00005) when compared with tumors with low Ki-67 values. In addition, this proliferative parameter maintained its prognostic significance when the patients were stratified according to lymph node involvement, menopausal status, and nuclear estrogen receptor content. CONCLUSIONS .

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We have investigated the molecular and biochemical basis for activation of interleukin 3 (IL3) gene expression in primary human T lymphocytes following CD3 and CD2 receptor stimulation or activation by phytohemagglutinin plus phorbol 12-myristate 13-acetate. Using transfection and reporter gene assays specifically designed for primary T lymphocytes in conjunction with gel retardation assays, Western blot analyses and UV cross-linking studies, we found that c-Jun, c-Fos, and octamer-binding proteins play a major role in transcriptional activation of the IL3 gene via their interaction with two specific regions contained within the IL3 5'-flanking sequence. Additionally, The data also These results

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We report two patients with transient pseudohypoaldosteronism due to obstructive renal disease. Both patients presented with a salt-losing episode simulating adrenal insufficiency. In one patient, transient reduction of aldosterone receptors could be documented, while in the second patient the clinical and biochemical parameters were consistent with transient pseudohypoaldosteronism. Aldosterone receptors were normal in both patients when studied after the surgical correction of the obstruction.

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The DNA-binding protein GATA-1 is required for normal erythroid development and regulates erythroid-expressed genes in maturing erythroblasts. We analyzed GATA-1 expression in early human adult hematopoiesis by using an in vitro system in which " pure " early hematopoietic progenitors are induced to gradual and synchronized differentiation selectively along the erythroid or granulocyte-macrophage pathway by differential treatment with hematopoietic growth factors. The GATA-1 gene, though virtually silent in quiescent progenitors, is activated after entrance into the cell cycle upon stimulation with hematopoietic growth factors. Subsequently, increasing expression along the erythroid pathway contrasts with an abrupt downregulation in the granulocyte-macrophage lineage. These results

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The Zfh family of zinc finger/homeodomain proteins was first identified in Drosophila where it is required for differentiation of tissues such as the central nervous system and muscle. ZEB, a vertebrate homolog of Zfh-1, binds a subset of E boxes and blocks myogenesis through transcriptional repression of muscle genes. We present evidence here that ZEB also has an important role in controlling hematopoietic gene transcription. Two families of transcription factors that are required for normal hematopoiesis are c-Myb and Ets. These factors act synergistically to activate transcription, and this synergy is required for transcription of at least several important hematopoietic genes. ZEB blocks the activity of c-Myb and Ets individually, but together the factors synergize to resist this repression. Such repression imposes a requirement for both c-Myb and Ets for transcriptional activity, providing one explanation for why synergy between these factors is important. The balance between repression by ZEB and transcriptional activation by c-Myb/Ets provides a flexible regulatory mechanism for controlling gene expression in hematopoietic cells. We demonstrate that one target of this positive/negative regulation in vivo is the alpha4 integrin, which play a key role in normal hematopoiesis and function of mature leukocytes.

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Alteration of gene transcription by inhibition of specific transcriptional regulatory proteins is necessary for determining how these factors participate in cellular differentiation. The functions of these proteins can be antagonized by several methods, each with specific limitations. Inhibition of sequence-specific DNA-binding proteins was achieved with double-stranded (ds) phosphorothioate oligonucleotides that contained octamer or kappa B consensus sequences. The phosphorothioate oligonucleotides specifically bound either octamer transcription factor or nuclear factor (NF)-kappa B. The modified oligonucleotides accumulated in cells more effectively than standard ds oligonucleotides and modulated gene expression in a specific manner. Octamer-dependent activation of a reporter plasmid or NF-kappa B-dependent activation of the human immunodeficiency virus (HIV) enhancer was inhibited when the appropriate phosphorothioate oligonucleotide was added to a transiently transfected B cell line. Addition of phosphorothioate oligonucleotides that contained the octamer consensus to Jurkat T leukemia cells inhibited interleukin-2 (IL-2) secretion to a degree similar to that observed with a mutated octamer site in the IL-2 enhancer. The ds phosphorothioate oligonucleotides

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Human immunodeficiency virus type-1 (HIV-1) transcription is dependent on the interaction of host-cell transcription factors with cis-regulatory DNA elements within the viral long terminal repeat (LTR). Much attention has focused on the series of sequence elements upstream of the transcriptional initiation site in the U3 region of the LTR including the Sp1 and NF-kappaB binding sites. Recent studies, however, demonstrate that the transcribed 5'-untranslated leader region (5'-UTR) also contains important transcriptional elements. These regulatory elements situated downstream of transcription interact with constitutive and inducible transcription factors, mediate transmission of cellular activation signals, and are important for efficient HIV-1 transcription and replication. The 5'-UTR contains binding sites for the transcription factors AP-1, NF-kappaB, NF-AT, IRF, and Sp1. Mutations in these binding sites can interfere with the viral response to cell activation signals, decrease LTR transcription, and inhibit viral replication. The 5'-UTR also interacts with a specific nucleosome that is rapidly displaced during transcriptional activation of the latent provirus. We In this review, we describe the host-cell transcription factors that interact with the 5'-UTR and discuss their role in the transcriptional regulation of HIV-1 gene expression.

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Analysis of the major histocompatibility complex class II gene promoter DRA has previously identified at least five cis-acting regions required for maximal expression. We have examined the DRA promoter for protein-DNA interactions in the intact cell, which Using in vivo genomic footprinting we identified interactions in B-cell lines at the octamer site and the Y, X1, and X2 boxes. Class II antigen expressing T-cell lines maintained contacts identical to B-cell lines, while class II-negative T-cell lines exhibited In lymphoid cell lines, the octamer site is occupied and required for maximal expression. This is most In contrast, the class II-positive nonlymphoid glioblastoma cell line does Thus, the DRA promoter discriminates against OTF-1 activation at the level of DNA binding in the glioblastoma line. Interferon gamma induces class II expression in this glioblastoma cell line and , in parallel, up-regulates X1 and X2 box protein-DNA interactions, while all other interactions remain unchanged. These results These findings provide direct in vivo evidence to strongly

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The role of the transcription factor NF-kappaB in the pathogenesis of rheumatoid arthritis has long been a subject of controversy. We used an adenoviral technique of blocking NF-kappaB through overexpression of the inhibitory subunit IkappaBalpha, which has the advantage that it can be used in the diseased tissue itself, with >90% of the synovial macrophages, fibroblasts, and T cells infected. We found that the spontaneous production of tumor necrosis factor alpha and other pro-inflammatory cytokines is NF-kappaB-dependent in rheumatoid synovial tissue, in contrast to the main anti-inflammatory mediators, like IL-10 and -11, and the IL-1 receptor antagonist. Of even more interest, IkappaBalpha overexpression inhibited the production of matrix metalloproteinases 1 and 3 while Blocking NF-kappaB in the rheumatoid joint thus has a very beneficial profile, reducing both the inflammatory response and the tissue destruction. The adenoviral technique described here has widespread applicability, allowing rapid testing of the effects of blocking a potential therapeutic target in either cultures of normal cells or in the diseased tissue itself.

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The region downstream of the enhancer (DEN) of the long terminal repeat of the mink cell focus-forming murine leukemia virus is important for viral pathogenicity. Another important activity of DEN is its control of transcription in activated T cells, and we have determined that an NF-kappaB site is critical for this activity.

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The binding of interleukin-2 (IL-2) to its receptor on normal T cells induces nuclear expression of nuclear factor kappaB (NF-kappaB), activation of the IL-2 receptor (IL-2R) alpha chain gene, and cell proliferation. In the present study, the role of IL-2R signaling in the growth of CD8+ T cell prolymphocytic leukemia (T-PLL) cells has been investigated. Flow cytometry revealed that primary leukemia cells from a patient with CD8+ T-PLL expressed IL-2Ralpha and beta chains, and the cells showed a proliferative response and an increase in IL-2Ralpha expression on culture with exogeneous IL-2. Northern blot analysis Electrophoretic mobility-shift assays revealed that recombinant IL-2 increased NF-kappaB binding activity in nuclear extracts of the leukemia cells, and Northern blot analysis showed that IL-2 increased the abundance of mRNAs encoding the NF-kappaB components c-Rel and KBF1 in these cells. IL-2 binding analysis demonstrated that IL-2 markedly increased the number of low affinity IL-2Rs on the leukemia cells, These results show that IL-2 is capable of inducing the nuclear expression of NF-kappaB in primary CD8+ T-PLL cells, and that this effect is mediated, at least in part, at a pretranslational level.

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CD40-stimulated human B lymphocytes are highly permissive to a productive infection by the human immunodeficiency virus type 1. In these cells, nuclear factors involved in activation of the HIV-1 LTR, which contains the transcriptional control elements of the virus, are unknown. Transient expression assays with plasmids containing deleted parts of the LTR region linked to a reporter gene showed that the NF-kappaB binding site was essential for HIV-1 LTR activity in CD40-stimulated B lymphocytes. In addition, electrophoretic mobility shift and supershift assays revealed that important NF-kappaB binding activity composed of at least p50, p65, and c-Rel NF-kappaB subunits was present in nuclei of CD40-stimulated B cells. These results confirm at a molecular level the ability of HIV-1 to replicate in B cells and that this activity is strongly associated with NF-kappaB.

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The gene encoding the 105-kDa protein (p105) precursor of the p50 subunit of transcription factor NF-kappa B also encodes a p70 I kappa B protein, I kappa B gamma, which is identical to the C-terminal 607 amino acids of p105. Here we show that alternative RNA splicing generates I kappa B gamma isoforms with properties different from those of p70. One 63-kDa isoform, termed I kappa B gamma-1, which A 55-kDa isoform, I kappa B gamma-2, In contrast to p70I kappa B gamma, which is a cytoplasmic protein, I kappa B gamma-1 is found in both the cytoplasm and nucleus, whereas I kappa B gamma-2 is predominantly nuclear. The I kappa B gamma isoforms also display differences in specificity and affinity for Rel/NF-kappa B proteins. While p70I kappa B gamma inhibits p50-, p65-, and c-Rel-mediated transactivation and/or DNA binding, both I kappa B gamma-1 and I kappa B gamma-2 are specific for p50 and have different affinities for this subunit. The

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Two cis-acting elements GM-kappa B/GC-box and CLE0, of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene are required for maximal induction in Jurkat T cells by costimulation with phorbol-12-myristate acetate (PMA) and Ca2+ ionophore (A23187). The GM-kappa B sequence is recognized by NF-kappa B, which is mainly induced by PMA. The CLE0 sequence interacts with factors, related to a PMA-induced AP-1 and a PMA/A23187-induced NF-AT. We examined Cotransfection of NF-kappa B (p50/p65)- or AP-1 (c-Jun/c-Fos)- expression vectors into Jurkat cells with a luciferase reporter containing the GM-CSF promoter did In contrast, cotransfection with a combination of NF-kappa B and AP-1 significantly augmented transcription from the GM-CSF promoter containing the GM-kappa B/GC-box and the CLE0 (AP-1/NF-AT). Expression of a constitutively active calcineurin (CN), a Ca2+/calmodulin-dependent protein phosphatase, potentiated by two fold the transcriptional activation by NF-kappa B/AP-1. Both constitutively active forms of CN and protein kinase C (PKC) synergistically activated transcription from the GM-CSF promoter. These results

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Chromosome 1 abnormalities with loss of 1p36 have been investigated in 95 breast-cancer samples by means of a dual-target fluorescence in-situ hybridization (FISH) technique using the pUC 1.77 and p1-79 probes, specific for the 1q12 and 1p36 regions, respectively. Abnormalities for Relative 1p36 under-representation was found in 79/95. The clinical relevance of these alterations was studied by comparing the FISH results with several parameters currently used in breast-cancer pathology. Distinct patterns of chromosome 1 abnormalities were found among the histologic types of breast carcinoma. In ductal carcinomas, chromosome 1 alterations increased with histologic grade, DNA aneuploidy, loss of bcl-2 and high c-erb B-2 expression. These associations were found to be statistically significant. These results indicate the utility of this FISH technique for a better definition of the biological characteristics of ductal carcinomas.

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Rheumatoid arthritis is a multistep disorder associated with autoimmune features of yet unknown etiology. Here we show that a large fraction of T cells infiltrating affected joints from a patient with chronic rheumatoid arthritis recognizes two EBV transactivators (BZLF1 and BMLF1) in a major histocompatibility complex-restricted fashion. Responses to these EBV antigens by synovial lymphocytes from several other chronic rheumatoid arthritis patients were readily detectable. Thus these results They also demonstrate for the first time the occurrence of T cell responses against EBV transactivating factors, which

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Thrombopoietin (TPO) acts on megakaryopoiesis and erythropoiesis in vitro and in vivo. We isolated a novel subline, UT-7/GMT, from the human leukemia cell line UT-7/GM (N. Komatsu, et al., Blood, 89: 4021-4033, 1997). A small population of UT-7/GM cells positively stained for hemoglobin (Hb) after a 7-day exposure to TPO. More than 50% of TPO-treated UT-7/GMT cells positively stained for Hb. Using UT-7/GMT cells, we examined how TPO promotes hemoglobinization. TPO induced tyrosine phosphorylation of the TPO receptor but There was These findings Isoelectric focusing demonstrated that TPO induced fetal and adult Hb synthesis, whereas EPO induced embryonic, fetal, and adult Hb synthesis. Thus, our data

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Currently available data Acute megakaryoblastic leukemia (AML-M7) and transient myeloproliferative disorder in Down 's syndrome (TMD) are characterized by rapid growth of abnormal blast cells which express megakaryocytic markers. These blast cells express lineage-specific transcription factors such as GATA-1 common to these lineages and frequently express erythroid-specific mRNAs such as gamma-globin and erythroid delta-aminolevulinate synthase (ALAS-E), These results

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1,25 alpha-Dihydroxicholecalciferol (VitD3) and retinoic acid (RA) are important regulators of the proliferation and differentiation of several cell types. This paper describes how the expression of the monocyte-macrophage Ag, CD14, and the low affinity Fc receptor for IgE, CD23, were inversely regulated during VitD3- and RA-induced monocytic differentiation of human U-937 monoblasts. PMA induced the expression of both CD14 and CD23 mRNA and protein. Exposure to VitD3 rapidly induced the de novo expression of CD14 mRNA and protein. The addition of cycloheximide completely blocked the VitD3 induction of CD14 mRNA expression, While inducing CD14 expression, VitD3 concomitantly suppressed the basal, PMA-, and RA-inducible CD23 expression in a dose-dependent manner. In contrast, U-937 cells induced by RA strongly increased their expression of CD23 mRNA and protein, whereas they completely Furthermore, the VitD3- and the PMA-induced CD14 expression was inhibited as a temporal consequence of the RA-induced differentiation. The results

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A factor in bovine colostrum (colostrum inhibitory factor, CIF) inhibits interleukin 2 (IL2) production in activated T helper cells by blocking the accumulation of IL2 mRNA. To determine These contained the luciferase gene under the control of either the human IL2 upstream enhancer region (segments -326 to +45) or three repeats of the NFAT element contained within it (segments -255 to -285). Expression of luciferase in these cells was induced by phorbol myristate acetate plus a calcium ionophore. CIF inhibited induction of either construct as did cyclosporine, which is known to block activation of the NFAT element. CIF The NFAT-controlled luciferase gene system distinguishes CIF from other T cell inhibitory activities present in colostrum, in particular, TGF beta 1 and TGF beta 2 and the glucocorticoids. Stably transfected Jurkat cells behaved similarly to the transiently transfected ones with respect to inhibition by CIF and cyclosporine. The NFAT-luc assay is a useful technique for the rapid, sensitive measurement of CIF or other immunosuppressants with a similar mode of action.

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Retinoic acid ( RA ) -induced maturation mediated by the retinoic acid receptor alpha (RAR alpha) has been implicated in myeloid development. We have used differential hybridization analysis of a cDNA library constructed from the murine RA-inducible MPRO promyelocyte cell line to identify immediate-early genes induced by RA during granulocytic differentiation. E3, one of nine sequences identified, was upregulated in an immediate-early manner, with transcript levels peaking after 60 minutes exposure to RA. E3 transcripts were RA-inducible in HL60 cells, but However, when HL60R cells were transduced with a functional copy of the RAR alpha gene, RA induced a 10-fold increase in E3 mRNA levels. E3 transcripts are present in the myeloid, B-lymphoid, and erythroid lineages, absent in nonhematopoietic cells, and encode a highly hydrophobic, The murine E3 promoter harbors a single bipartite retinoic acid response element which in transient transfection assays conferred RA sensitivity. These results

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The human erythroleukemia cell line K562 can be induced to differentiate along the erythroid and megakaryocytic lineages. Here we demonstrate that hexamethylene bisacetamide (HMBA) induced K562 cells to differentiate along a third pathway. This was accompanied by downregulation of two transcription factors normally expressed in erythroid, mast and megakaryocyte lineages. Northern analysis demonstrated coordinate downregulation of alpha globin and gamma globin in addition to the two lineage-restricted transcription factors, SCL and GATA-1. Proliferation of the K562 cells was also suppressed. Clonal assay showed that the suppression was irreversible and In contrast to MEL cells, however, K562 cells acquired a macrophage-like morphology and exhibited a complete failure to generate benzidine-positive cells. Electron microscopy revealed a marked increase in granules resembling those specific for eosinophils. Surface marker analysis showed that HMBA-induced cells expressed reduced levels of glycophorin A, CD5, CD7 and CD11b. Thus the response of K562 cells to HMBA

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B-cell-specific transcription of immunoglobulin genes is mediated by the interaction of a POU domain containing transcription factor Oct-1 or Oct-2, with the B-cell-specific coactivator OCA-B (Bob-1, OBF-1) and a prototype octamer element. We find that OCA-B binds DNA directly in the major groove between the two subdomains of the POU domain, requiring both an A at the fifth position of the octamer element and contact with the POU domain. An amino-terminal fragment of OCA-B binds the octamer site in the absence of a POU domain with the same sequence specificity. Coactivator OCA-B The recognition of both the POU domain and the octamer sequence by OCA-B provides a mechanism for differential regulation of octamer sites containing genes by the ubiquitous factor Oct-1.

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Here we report that this interference is cell specific, as TPA augmented dexamethasone-induced transcriptional activation of the MMTV LTR in several T cell lines but was inhibitory in NIH-3T3 fibroblasts. TPA-GR synergism was determined to have occurred at the GR-responsive element (GRE) level by functional analysis of deletion mutants or synthetic GRE oligonucleotides driving chloramphenicol acetyl-transferase expression. Synergism required an intact GR DNA-binding domain, whereas amino- or carboxyl-terminal domains were dispensable. The effect was abrogated by the PKC inhibitor staurosporine, Increased c-jun, jun-B, and jun-D expression above basal levels and increased transcriptional activity of AP-1/TPA responsive elements fused to chloramphenicol acetyl-transferase vectors were observed in T cells treated with TPA alone or in combination with dexamethasone. The ability of Jun proteins to cooperate with GR in T cells has been investigated after transfection of c-jun, jun-B, or jun-D expression vectors, which augmented GR-dependent transcription from either MMTV LTR or GRE. Conversely, c-jun and jun-B transfection blunted GR-dependent transcription in HeLa cells. The presence of c-fos had a negative influence on GR function and correlated with the cell-specific synergistic or antagonistic activity of Jun with respect to GR; high basal expression of c-fos as well as AP-1 DNA binding and transcriptional activity were observed in HeLa cells, but Furthermore overexpression of exogenous c-fos has an inhibitory effect on GR-dependent transcription from GRE in T cells. We In this regard,

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Previous studies have However, A mAb, R24, that reacts specifically with a cell surface ganglioside (GD3) has been demonstrated to stimulate proliferation of T cells derived from human peripheral blood. In this study, we have investigated the mechanisms by which the R24 mAb affects T cell functions. We have observed that the R24 mAb stimulates GD3+ T cell proliferation, cytotoxicity, and surface marker expression of IL-2R alpha-chain, IL-2R beta-chain, HLA-DR, CD11a, and CD11c. Additionally, IFN-gamma activity but In some donors, increased IL-6 and TNF-alpha activity also was detected after R24 treatment. Furthermore, R24 treatment resulted in translocation of c-rel, but This treatment also caused increased tyrosine phosphorylation of specific protein substrates. Additionally, herbimycin A, a tyrosine kinase inhibitor, blocked the R24-stimulated increase in proliferation but These results

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Cyclosporine (CsA) is both a clinical immunosuppressive drug and a probe to dissect intracellular signaling pathways. In vitro, CsA inhibits lymphocyte gene activation by inhibiting the phosphatase activity of calcineurin (CN). In clinical use, CsA treatment inhibits 50-75% of CN activity in circulating leukocytes. We modeled this degree of CN inhibition in primary human leukocytes in vitro in order to study the effect of partial CN inhibition on the downstream signaling events that lead to gene activation. In CsA-treated leukocytes stimulated by calcium ionophore, the degree of reduction in CN activity was accompanied by a similar degree of inhibition of each event tested: dephosphorylation of nuclear factor of activated T cell proteins, nuclear DNA binding, activation of a transfected reporter gene construct, IFN-gamma and IL-2 mRNA accumulation, and IFN-gamma production. Furthermore, the degree of CN inhibition was reflected by a similar degree of reduction in lymphocyte proliferation and IFN-gamma production in the allogeneic mixed lymphocyte cultures. These data support the conclusion that CN activity is rate-limiting for the activation of primary human T lymphocytes. Thus, the reduction of CN activity observed in CsA-treated patients is accompanied by a similar degree of reduction in lymphocyte gene activation, and accounts for the immunosuppression observed.

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A DNA probe that spanned a domain conserved among the proto-oncogene c-rel, the Drosophila morphogen dorsal, and the p50 DNA binding subunit of NF-kappa B was generated from Jurkat T cell complementary DNA with the polymerase chain reaction (PCR) and degenerate oligonucleotides. This probe was used to identify a rel-related complementary DNA that hybridized to a 2.6-kilobase messenger RNA present in human T and B lymphocytes. In vitro transcription and translation of the complementary DNA resulted in the synthesis of a protein with an apparent molecular size of 65 kilodaltons (kD). The translated protein showed weak DNA binding with a specificity for the kappa B binding motif. This protein-DNA complex comigrated with the complex obtained with the purified human p65 NF-kappa B subunit and binding was inhibited by I kappa B-alpha and -beta proteins. In addition, the 65-kD protein associated with the p50 subunit of NF-kappa B and the kappa B probe to form a complex with the same electrophoretic mobility as the NF-kappa B-DNA complex. Therefore the rel-related 65-kD protein

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Steel factor is one of the growth factors that controls the proliferation and differentiation of hematopoietic cells and SCL, also known as Tcl-5 or Tal-1, is a transcription factor involved in erythropoiesis. In this report, we studied the role of SCL in the proliferation of human peripheral blood burst-forming unit-erythroid (BFU-E) and the effects of Steel factor on SCL expression in proliferating erythroid cells. BFU-E-derived colonies increase progressively in size, as determined by cell number, from day 7 to day 14 of culture, with the greatest increase in colony size (10-fold expansion) occurring between day 7 and day 10. SCL protein levels in BFU-E-derived cells were highest in day 7 cells and decreased progressively from day 7 to day 14 of culture, In contrast, SCL mRNA levels did The role of SCL in Steel factor-induced erythroid proliferation was then examined. In BFU-E-derived colonies cultured with Steel factor, colony size was significantly increased compared to control. In day 7 and day 10 erythroid precursors cultured with Steel factor, SCL protein was increased significantly compared to control. The increase in SCL protein levels in early erythroid precursors stimulated with Steel factor SCL mRNA levels assessed by Northern blot in day 7 cells did not increase significantly in response to Steel factor stimulation,

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The protein products of the c-fos (p62c-fos) and c-jun (p39c-jun) genes are members of the AP-1 transcription factor family and Most studies on the expression of these proteins in relation to the cell cycle have been performed at the mRNA level, and therefore do We have used Western blotting to investigate the presence of these proteins during the cell cycles of two different cellular systems: a continuously growing myeloid leukemic cell line, HL60, and normal cells stimulated into cycle, phyto- hemagglutinin (PHA)-stimulated normal human peripheral blood lymphocytes (PBL). The binding activity of transcription factor AP-1, which consists of dimers of Fos and Jun family proteins, was also studied using a gel shift assay. We found nuclear p62c-fos, p39c-jun, and AP-1 binding activity throughout the cell cycle both in HL60 cells and in PHA-stimulated PBL, and we postulate that these proteins are required throughout the cell cycle and We demonstrated an uncoupling of AP-1 binding activity from p62c-fos, and p39c-jun AP-1 activity was expressed more strongly in the G1- and G2/M-phase enriched samples than in the S-phase enriched samples of HL60 cells, while levels of nuclear p62c-fos and p39c-jun were constant. Nuclei of unstimulated PBL from different donors expressed p62c-fos and p39c-jun, but Following PHA stimulation of PBL, the increase in AP-1 activity was delayed with respect to the augmentation of p39c-jun expression. We also observed that cytoplasmic p62c-fos and p39c-jun were present in HL60 cells and PHA-stimulated PBL. However,

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N-acetyl-L-cysteine (NAC) is an antioxidant molecule endowed with immunomodulatory properties. To investigate the effect of NAC on the induction phase of T cell responses, we analyzed its action on human dendritic cells (DC) derived from adherent PBMC cultured with IL-4 and granulocyte-macrophage CSF. We first found that NAC inhibited the constitutive as well as the LPS-induced activity of the transcription factor NF-kappaB. In parallel, NAC was shown to down-regulate the production of cytokines by DC as well as their surface expression of HLA-DR, CD86 (B7-2), and CD40 molecules both at the basal state and upon LPS activation. NAC also inhibited DC responses induced by CD40 engagement. The inhibitory effects of NAC were Finally, we found that the addition of NAC to MLR between naive T cells and allogeneic DC resulted in a profound inhibition of alloreactive responses, Altogether, our results

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Mature human lymphocytes are unique targets of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) in that vitamin D receptors (VDR) are Treatment of B lymphocytes with the cytokine IL-4 (IL-4), in the absence of prior activation, induces a weak up-regulation of VDR expression but Stimulation of B lymphocytes by either ligation of CD40 Ag or cross-linking the Ig receptor is also insufficient to render B lymphocytes responsive to 1 alpha,25(OH)2D3. However, In the presence of 1 alpha,25(OH)2D3, Furthermore, biologic functions are modulated, in that the hormone inhibits proliferation in a subset of the activated B cells. These observations

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Interleukin-10 (IL-10) and transforming growth factor beta (TGF-beta) are inhibitory for B and T cells, IgE production, and mast cell proliferation, and they induce apoptosis in eosinophils. These cytokines are therefore candidate genes which We investigated the DNA taken from families with an asthmatic proband was examined for base exchanges by single-stranded conformational polymorphism (SSCP). We demonstrated the presence of a polymorphism in the promoter region of the IL-10 gene and four in the TGF-beta gene promoters (3 in TGF-beta1 and 1 in TGF-beta2). The IL-10 gene polymorphism was a C-to-A exchange 571 base pairs upstream from the translation start site and was present between consensus binding sequences for Sp1 and elevated total serum. This polymorphism was associated with elevated total serum IgE in subjects heterozygotic or homozygotic for this base exchange (p < 0.009). The base exchange at -509 (from the transcription initiation site) in the TGF-beta promoter also linked to elevated total IgE (p < 0.01). This polymorphism represented a C-to-T base exchange which induced a YY1 consensus sequence and is present in a region of the promoter associated with negative transcription regulation.

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Dysregulation of cytokines secreted by T cells To investigate the effects of human immunodeficiency virus type 1 (HIV-1) Tat on interleukin-2 (IL-2) expression, we used IL-2 promoter-chloramphenicol acetyltransferase constructs and IL-2-secreting Jurkat T cells as a model system. Transient expression of HIV-1 Tat induced a five- to eightfold increase in IL-2 promoter activity in Jurkat T cells stimulated with phytohemagglutinin and phorbol myristate acetate. IL-2 secretion was increased more than twofold in both Jurkat T cells and primary T cells stimulated by extracellular HIV-1 Tat protein. Analysis of mRNA The NF-kappa B site at positions -206 to -195 of the IL-2 promoter was required but The Tat-mediated increase in IL-2 promoter activity could selectively be blocked by antisense tat or-unlike the analogous effect of human T-cell lymphotropic virus type 1 Tax-by cyclosporin A. The observed increase in IL-2 levels Furthermore, it

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The c-rel protooncogene encodes a subunit of the NF-kappa B-like family of transcription factors. Mice In an attempt to identify changes in gene expression that accompany the T-cell stimulation defects associated with the loss of Rel, we have examined the expression of cell surface activation markers and cytokine production in mitogen-stimulated Rel-/- T cells. The expression of cell surface markers including the interleukin 2 receptor alpha (IL-2R alpha) chain (CD25), CD69 and L-selectin (CD62) is normal in mitogen-activated Rel-/- T cells, but cytokine production is impaired. In Rel-/- splenic T cell cultures stimulated with phorbol 12-myristate 13-acetate and ionomycin, the levels of IL-3, IL-5, granulocyte- macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor alpha (TNF-alpha), and gamma interferon (IFN-gamma) were only 2- to 3-fold lower compared with normal T cells. In contrast, anti-CD3 and anti-CD28 stimulated Rel-/- T cells, which Exogenous IL-2, which restitutes the proliferative response of the anti-CD3- and anti-CD28-treated Rel-/- T cells, restores production of IL-5, TNF-alpha, and IFN-gamma, but In contrast to mitogen-activated Rel-/- T cells, lipopolysaccharide-stimulated Rel-/- macrophages produce higher than normal levels of GM-CSF. These findings establish that Rel can function as an activator or repressor of gene expression and is required by T lymphocytes for production of IL-3 and GM-CSF.

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We have recently demonstrated that hydrocortisone and other glucocorticoids inhibit reactive oxygen species (ROS) generation by mononuclear (MNC) and polymorphonuclear leucocytes (PMNL). Since NF-kappaB/IkappaB system regulates the transcription of proinflammatory genes, including those responsible for ROS generation, we tested the hypothesis that hydrocortisone One hundred milligram of hydrocortisone was injected intravenously into 4 normal subjects. Blood samples were obtained prior to the injection and at 1, 2, 4, 8 and 24 hr after the injection. Nuclear extracts and total cell lysates were prepared from MNC by standard techniques. IkappaB levels in MNC homogenates increased at 1 hr, peaked at 2-4 hr, started to decrease at 8 hr, and returned to baseline levels at 24 hr. NF-kappaB in MNC nuclear extracts decreased at 1 hr, reached a nadir at 4 hr, gradually increased at 8 hr and returned back to baseline levels at 24 hr. The total protein content of NF-kappaB subunit (P65) in MNC lysates also showed a decrease following hydrocortisone injection. This decrease was observed at 2 hr, reached a nadir at 4 hr, and returned to baseline levels at 24 hr. ROS generation inhibition paralleled NF-kappaB levels in the nucleus. It was inhibited at 1 hr, reached a nadir at 2-4 hr, started to increase at 8 hr, and returned to basal levels at 24 hr. Our data demonstrate that hydrocortisone induces IkappaB and suppresses NF-kappaB expression in MNC in parallel. IkappaB further reduces the translocation of NF-kappaB into the nucleus thus preventing the expression of proinflammatory genes.

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The regulatory effect of insulin on the specific binding power of glucocorticoid receptor (GR) of human leukocytes was assessed by the unoccupied receptor sites capable of combining with [3H] labelled dexamethasone measured at 3 and 24 h after incubation with various concentrations of insulin added to the medium. After 3 h incubation the specific binding power with [3H] Dex was decreased by 23.3 ± 10.0, 32.2 ± 13.2 and 54.3 ± 9.2% (P greater than 0.05, P greater than 0.05 and P less than 0.01 as compared with the control value of 100 in the absence of insulin) respectively in the presence of 20 mU/L (physiological testing concentration), 200 mU/L (physiological upper limit) and 2,000 mU/L (pharmacological concentration) insulin in the incubation medium. After 24 h incubation the decrease of these values increased respectively to 43.5 ± 19.0, 56.1 ± 20.7 and 80.2 ± 15.5 (P less than 0.05, P less than 0.01 and P less than 0.01 compared with control). Thus the inhibitory effect of insulin on the GR binding power is both dose- and time-dependent, which strongly

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B-cell immortalization by Epstein-Barr virus (EBV) is dependent on permanent control of the cellular processes which normally regulate cell division and apoptosis, functions possessed by p53 in a number of normal cell types. In studies initiated to evaluate relationships between EBV latent genes and p53, p53 levels were found to increase approximately 10-fold 4 to 5 days after EBV infection of purified resting human B cells; the induced p53 was transcriptionally active. Latent membrane protein 1 and, to a lesser extent, EBV nuclear antigen 2 mediated the increase in p53 levels via activation of the NF-kappaB transcription factor.

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To determine We demonstrate that the NF-microB-binding site plays a critical role in the IgH enhancer, because mutation of the microB DNA motif decreased transcriptional activity of the IgH enhancer in cells of the B-cell lineage but This effect was comparable to or even stronger than the effect of a mutation in the OCTA site. Moreover, combined mutation of both microB and OCTA sites further reduced enhancer activity in lymphoid cells. Interestingly, alteration of either the microB or E3 site in a 70-base-pair fragment of the IgH enhancer that Nevertheless, a multimer of the microB motif alone showed DNase footprinting analysis corroborated the functional data showing that a lymphoid-specific protein binds to the microB DNA motif. Our results

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As the NF-kappa B transcription factor has a central role in the control of transcription of several genes involved in immune and inflammatory responses, the authors have analysed the activation of NF-kappa B in human umbilical cord T lymphocytes. The activity was tested by quantitating the nuclear proteins binding to an oligonucleotide containing the consensus kappa B binding sequence (electrophoretic mobility shift assay). The data obtained demonstrate that phorbol dibutyrate/calcium ionophore A23187 (PDBu/iono) combination induced a clearly higher nuclear translocation of NF-kappa B in neonatal than adult T cells. This higher NF-kappa B activity was restricted to the CD4+ T-cell subset. Analysis of the nuclear extracts with antibodies directed against the major components of NF-kappa B the p50 and RelA (p65) proteins , indicated that the composition of NF-kappa B was similar in neonatal and adult cells. These results

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Stimulation of T cells with antigen results in activation of several kinases, including protein kinase C (PKC), that We have examined the potential role of PKC in induction of the interleukin 2 (IL-2) gene in T cells stimulated through the T cell receptor/CD3 complex. We have previously shown that prolonged treatment of the untransformed T cell clone Ar-5 with phorbol esters results in downmodulation of the alpha and beta isozymes of PKC, and abrogates induction of IL-2 mRNA and protein. Here we show that phorbol ester treatment also abolishes induction of chloramphenicol acetyltransferase activity in Ar-5 cells transfected with a plasmid containing the IL-2 promoter linked to this reporter gene. The IL-2 promoter contains binding sites for nuclear factors including NFAT-1, Oct, NF-kappa B, and AP-1, which are all We show that induction of a trimer of the NFAT and Oct sites is In contrast, mutations in the AP-1 site located at -150 bp almost completely abrogate induction of the IL-2 promoter, and appearance of an inducible nuclear factor binding to this site is sensitive to PKC depletion. Moreover, cotransfections with c-fos and c-jun expression plasmids markedly enhance induction of the IL-2 promoter in minimally stimulated T cells. Our results

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This paper presents studies of G0S2, a member of a set of G0S2 mRNA increases transiently within 1-2 hr of the addition of lectin or cycloheximide to cultured blood mononuclear cells. Comparison of a nearly full-length cDNA sequence with the corresponding genomic sequence reveals one small intron and an open reading frame in the second exon. The derived 103-amino-acid basic protein has two potential alpha-helical domains separated by a hydrophobic region with the potential to generate turns and assume a beta-sheet conformation. Consistent with involvement in the G0/G1 switch, the protein contains potential sites for phosphorylation by protein kinase C and casein kinase II. The gene contains a CpG-rich island An upstream segment contains tandem dinucleotide repeats (CT)19/(CA)16. There is a suitably located TATA box, but

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Peripheral blood lymphocytes (PBL) and alloreactive T cell lines of two male infants born to consanguinous parents and presenting with severe combined immunodeficiency (SCID) showed a pronounced deficiency in T cell activation. Although phenotypically normal, the proliferative response of the childrens ' T cells was strongly reduced but could be improved by the addition of interleukin-2 (IL-2). Furthermore both childrens ' T cells were Moreover, In contrast, expression of the activation-dependent cell surface markers CD25 and CD69 was within normal limits. To determine Whereas AP-1, NF-kappa B, Oct, CREB and SP1 displayed normal binding activities in nuclear extracts, the binding of NF-AT to its IL-2 promoter response element was barely detectable both before and after T cell stimulation. Our results strongly

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The nuclear factor of activated T cells (NFAT) group of transcription factors is retained in the cytoplasm of quiescent cells. NFAT activation is mediated in part by induced nuclear import. This process requires calcium-dependent dephosphorylation of NFAT caused by the phosphatase calcineurin. The c-Jun amino-terminal kinase (JNK) phosphorylates NFAT4 on two sites. Mutational removal of the JNK phosphorylation sites caused constitutive nuclear localization of NFAT4. In contrast, JNK activation in calcineurin-stimulated cells caused nuclear exclusion of NFAT4. These findings show that the nuclear accumulation of NFAT4 promoted by calcineurin is opposed by the JNK signal transduction pathway.

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The adherence of monocytes to activated endothelium is an early event in atherogenesis. Because antioxidants have been considered to be of antiatherosclerotic potential, we investigated the effects of alpha-tocopherol (TCP) and its acetate and succinate esters on monocyte adhesion to cytokine-stimulated human umbilical vein endothelial cells (HUVEC). Endothelial cells were treated with TCP, alpha-tocopherol acetate (TCP acetate), or alpha-tocopheryl succinate (TCP succinate) before stimulation with tumor necrosis factor-alpha (TNF-alpha; 10 U/ml, 6 h) or interleukin-1 beta (IL-1 beta; 10 U/ml, 6 h). Cytokine-stimulated cell surface expression of vascular cell adhesion molecule-1 (VCAM-1, CD106) and E-selectin (ELAM-1, CD62E), but TCP succinate (200 microM, 24 h) reduced TNF-induced VCAM-1 and E-selectin expression from a specific mean fluorescence intensity of 151 ± 28 to 12 ± 4 channels and from 225 ± 38 to 79 ± 21 channels, respectively. Succinate alone had Decreased adhesion molecule expression was associated with a reduction of monocytic cell adhesion. TCP succinate (20 microM, 72 h), but Electrophoretic mobility-shift assays of HUVEC nuclear proteins revealed a decrease in TNF-alpha-stimulated nuclear factor-kappa B (NF-kappa B) activation after pretreatment of HUVEC with TCP succinate but In conclusion, we demonstrate that the vitamin E derivative TCP succinate prevents monocytic cell adhesion to cytokine-stimulated endothelial cells by inhibiting the activation of NF-kappa B, further emphasizing the antiatherosclerotic potential of lipid soluble antioxidants.

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Activity of the immunoglobulin heavy and kappa light chain gene enhancers depends on a complex interplay of ubiquitous and developmentally regulated proteins. Two complementary DNAs were isolated that encode proteins, denoted ITF-1 and ITF-2, that are expressed in a variety of cell types and bind the microE5/kappa 2 motif found in both heavy and kappa light chain enhancers. The complementary DNAs are the products of distinct genes, yet both ITF-1 and ITF-2 are structurally and functionally similar. The two proteins interact with one another through their putative helix-loop-helix motifs and each possesses a distinct domain that dictates transcription activation.

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The granulocyte-macrophage colony-stimulating factor (GM-CSF) gene promoter contains a consensus sequence for the polyomavirus enhancer binding-protein 2 (PEBP2) transcription factor, which consists of alpha and beta subunits. There are at least two genes, alpha A and alpha B, encoding the alpha subunit. alpha B is the mouse homologue of human AML1 gene detected at the breakpoints of t(8;21) and t(3;21) myeloid leukemias. We examined alpha A1 (an alpha A-gene product) and alpha B1 and alpha B2 (two alpha B-encoded isomers) for their effects on the GM-CSF promoter. PEBP2 alpha A1, alpha B1, and alpha B2 proteins bound the PEBP2 site within the mouse GM-CSF promoter. PEBP2 alpha A1 and alpha B1 enhanced the expression of the GM-CSF promoter-driven reporter plasmid in unstimulated and 12-O-tetradecanoylphorbol 13-acetate/phytohemagglutinin-stimulated human Jurkat T cells. In contrast, the promoter activity was suppressed by alpha B2. Coexpression of alpha B1 and alpha B2 showed that the promoter activity could be determined by the alpha B1/alpha B2 ratio. Jurkat cell extract contained PEBP2 site-binding protein(s) that cross-reacted with antimouse alpha A1 antibodies. Northern blot analysis indicated the expression of human PEBP2 alpha A, alpha B (AML1), and beta genes in Jurkat cells. Although further studies are required to determine the precise role of PEBP2 in the GM-CSF promoter activity, the present findings

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Germline transcripts initiate from promoters upstream of the immunoglobulin switch region, and are necessary to target the appropriate switch region for recombination and switching. Different cytokines activate transcription at the appropriate germline promoter. Because binding sites for B-cell-specific activator protein (BSAP) are located upstream of several switch regions in the immunoglobulin heavy chain gene cluster, BSAP We investigated Our results showed that BSAP plays a role in both IL-4-dependent induction and CD40-mediated upregulation of human epsilon germline transcription. BSAP is unique among the transcription factors that regulate epsilon germline expression, because it is B cell specific, and is at the merging point of two signalling pathways that are critical for IgE switching.

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NF-kappa B is a nuclear protein of the rel oncogene family capable of enhancing transcription of several cellular genes, including IL-2 and the IL-2 receptor, and viral genes transcribed from the HIV-1 LTR. It has been reported that HIV-1 protease In this study the effects of HIV protease on NF-kappa B precursor activation were examined in Jurkat T cells by introducing a protease expression vector into the cells. Increased NF-kappa B activity was observed and this increased activity was blocked by a specific inhibitor of the viral protease. Viral transcription, as measured using LTR-CAT assays, was only slightly enhanced in the HIV-protease expressing cells, while

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The proximal sequence element ( PSE ) -binding transcription factor (PTF), which binds the PSE of both RNA polymerase II- and RNA polymerase III-transcribed mammalian small nuclear RNA (snRNA) genes, is essential for their transcription. We previously reported the purification of human PTF, a complex of four subunits, and the molecular cloning and characterization of PTF gamma and delta subunits. Here we describe the isolation and expression of a cDNA encoding PTF beta, as well as functional studies using anti-PTF beta antibodies. Native PTF beta, in either protein fractions or a PTF-Oct-1-DNA complex, can be recognized by polyclonal antibodies raised against recombinant PTF beta. Immunodepletion studies show that PTF beta is required for transcription of both classes of snRNA genes in vitro. In addition, immunoprecipitation analyses demonstrate that substantial and similar molar amounts of TATA-binding protein (TBP) and TFIIIB90 can weakly associate with PTF at low salt conditions, but this association is dramatically reduced at high salt concentrations. Along with our previous demonstration of both physical interactions between PTF gamma/PTF delta and TBP and the involvement of TFIIIB90 in the transcription of class III snRNA genes, these results are consistent with the notion that a TBP-containing complex related to TFIIIB is required for the transcription of class III snRNA genes, and acts through weak interaction with the four-subunit PTF.

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Recently, many investigators have been interested in the study on eosinophil biology since genes association with eosinophils such as interleukin-5 or eosinophil granule proteins (EPO, ECP, EDN, MBP, and CLC), were isolated. However, The mechanism by which eosinophil-specific genes encoding primary and secondary granule proteins (e.g. ECP, EDN, EPO, MBP, and CLC) are expressed and regulated during eosinophilopoiesis is also unknown. In this paper, I described the characterization of genes encoding eosinophil granule proteins and the mRNA expression of GATA-1 binding transcription factor during eosinophil differentiation.

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Elevation of the levels of circulating immune complexes frequently accompanies HIV-1 infection and is a prognostic indicator of clinical progression from asymptomatic infection to AIDS. Here we report that cross-linking of Fc gamma RI or Fc gamma RII by adherent human IgG or by specific anti-Fc gamma R mAb activates HIV-1 gene expression in the human monocytic cell line BF24 and increased HIV RNA expression in monocytes from HIV infected patients as assayed by reverse transcription-PCR. In THP-1 cells, Fc gamma R cross-linking induced NF-kappa B, which is known to bind to the regulatory region of the long terminal repeat (LTR) of HIV-1 and to activate HIV-1 transcription. Anti-TNF-alpha antibody but These results

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Cytokine dysregulation in human immunodeficiency virus type 1 (HIV-1) infection has been documented in numerous studies and has been cited as an important component in the pathogenesis of this retroviral infection. Dr. Dezube of Beth Israel Hospital (Boston) concisely reviews the state of our knowledge regarding the effects of pentoxifylline on expression of tumor necrosis factor-alpha, a cytokine known to influence HIV-1 replication and to play a Pentoxifylline, a trisubstituted xanthine derivative, has been used to decrease blood viscosity and is reasonably well tolerated by most recipients of the drug. Results of preliminary studies, many of which were conducted by Dr. Dezube,

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The purpose of this study was to examine the effects of bis[4-[2,4-dioxo-5-thiazolidinyl)methyl]phenyl]methane (YM-268), a thiazolidinedione derivative, on glucose uptake, adipocyte differentiation through peroxisome proliferator-activated receptor gamma(PPARgamma), and phosphatidylinositol 3-kinase (PI 3-kinase) activity in cultured cells. YM268 and pioglitazone dose-dependently increased the 2-deoxyglucose uptake in 3T3-L1 cells. YM268 facilitated the insulin-stimulated triglyceride accumulation in 3T3-L1 adipocytes and increased the mRNA expression of fatty acid-binding protein. YM268, with and Additionally, YM268 and pioglitazone showed activity of the PPARgamma ligand, a member of the nuclear receptor superfamily responsible for adipogenesis. To examine the Insulin dose-dependently increased the PI-3,4,5-P3 production but YM268 had These results

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Expression of the IgG Fc receptor type I (Fc gamma RI) on myeloid cells is dramatically increased by treatment with interferon-gamma (IFN-gamma). We observed that Fc gamma RI transcript levels in monoblast-like U937 cells were elevated within 3 hr and peaked 12 hr after exposure to IFN-gamma. Treatment of U937 with IFN-gamma for 9 hr in the presence of cycloheximide led to super-induction of Fc gamma RI expression. Nuclear run-on analysis revealed that the rate of Fc gamma RI transcription was increased by IFN-gamma. Genomic sequence upstream of the Fc gamma RIC gene was cloned and subjected to primer extension analysis, which demonstrated a single transcription initiation site Transient transfections of CAT reporter gene constructs containing various Fc gamma RIC promoter sequences into U937 cells revealed that a 20-bp region surrounding the transcription start site (-7 to +13) was capable of mediating transcription initiation and that an IFN-gamma responsive element (GIRE) was present within 74 bp upstream of the transcription initiation site. A 17-bp sequence between positions -51 and -35 conferred IFN-gamma responsiveness on a heterologous promoter. Double-stranded GIRE sequence, but Gel shift experiments further showed that the STAT1 alpha protein bound to the Fc gamma RIC GIRE in response to IFN-gamma treatment of U937 cells. The Fc gamma RIC GIRE is homologous to the IFN-gamma activation sequence (GAS) of the guanylate binding protein and to X box elements of class II MHC genes. Our results demonstrate that transcriptional regulation of the Fc gamma RIC gene by IFN-gamma involves the binding of STAT1 alpha to a 17-bp GAS homology in the proximal promoter.

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Treatment of the acute promyelocytic (APL) cell line NB4 with interferon alpha (IFN(alpha)), as well as IFN(beta) and gamma, results in an increased expression of the transcripts coding for retinoic-acid receptor type alpha (RAR(alpha)) and the leukemia-specific retinoic acid receptor PML-RAR. Transcriptional induction of the RAR(alpha) and PML-RAR mRNAs is rapid and it is parallelled by an increase in the corresponding proteins. Up-regulation of RAR(alpha) and PML-RAR gene expression by IFN(alpha) is accompanied by a strong potentiation in the induction of 2 retinoid-dependent granulocytic markers, i.e. , granulocyte-colony-stimulating factor receptor mRNA and leukocyte alkaline phosphatase. However, IFN(alpha) does The IFN-dependent increase in RAR(alpha) levels and the enhancing effect of the cytokine on retinoid-dependent granulocytic markers expression Interferons as well as retinoids inhibit the growth of NB4 cells, although the 2 classes of compounds do not significantly interact in terms of anti-proliferative activity. These results

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The enhancer for the immunoglobulin mu heavy chain gene (IgH) activates a heterologous gene at the pre-B cell stage of B lymphocyte differentiation. A lymphoid-specific element, microB, is necessary for enhancer function in pre-B cells. A microB binding protein is encoded by the PU.1/Spi-1 proto-oncogene. Another sequence element, microA, was identified in the mu enhancer that binds the product of the ets-1 proto-oncogene. The microA motif was required for microB-dependent enhancer activity, which Co-expression of both PU.1 and Ets-1 in nonlymphoid cells trans-activated reporter plasmids that contained the minimal mu enhancer. These results implicate two members of the Ets family in the activation of IgH gene expression.

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The NF-kappaB family of transcription factors regulates the inducible expression of a variety of genes. Recently, we showed that elevation of intracellular cyclic AMP inhibits NF-kappaB-mediated transcription in human monocytes and endothelial cells The present study examined the molecular mechanism of this inhibition. We Here, we show that the amino-terminal region (amino acids 1-450) of CBP specifically interacts with the carboxyl-terminal region (amino acids 286-551) of NF-kappaB p65 (RelA) both in vitro and in vivo. Functional studies using human endothelial cells demonstrated that overexpression of CBP rescued cAMP inhibition of NF-kappaB-mediated transcription and transcription mediated by a chimeric protein, GAL4-p65(286-551), which contained the GAL4 DNA binding domain fused to the carboxyl-terminal region of p65 (amino acids 286-551). In contrast, overexpression of CREB inhibited GAL4-p65(286-551)-mediated transcription. These results

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Adhesion molecules that tether circulating leukocytes to endothelial cells Adhesion of human monocytes to P-selectin, the most rapidly expressed endothelial tethering factor, increased the secretion of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) by the leukocytes when they were stimulated with platelet-activating factor. Increased cytokine secretion was specifically inhibited by G1, an anti-P-selectin mAb that prevents P-selectin from binding to its ligand (P-selectin glycoprotein ligand-1) on myeloid cells. Moreover, tethering by P-selectin specifically enhanced nuclear translocation of nuclear factor-kappa B (NF-kappa B), a transcription factor required for expression of MCP-1, TNF-alpha, and other immediate-early genes. These results demonstrate that P-selectin, through its ligands on monocytes,

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The macrophage colony-stimulating factor (M-CSF) is required for the growth and differentiation of mononuclear phagocytes. However, the signaling events responsible for these effects remain unclear. The present studies have examined the effects of M-CSF on potential signaling pathways involving expression of the jun and fos early response genes. Low levels of c-jun transcripts were detectable in resting human peripheral blood monocytes. Treatment of these cells with 10(3) units/ml human recombinant M-CSF was associated with rapid and transient increases in c-jun mRNA levels. Nuclear run-on assays and mRNA stability studies demonstrated that M-CSF regulates c-jun expression by both an increase in transcription rate and a prolongation in the half-life of c-jun transcripts. M-CSF treatment was also associated with a rapid induction of the jun-B gene, although expression of this gene was prolonged compared to that of c-jun. We further demonstrate that M-CSF increases c-fos mRNA levels in human monocytes through control at both the transcriptional and posttranscriptional levels. Maximal induction of the c-fos gene was followed by that for the fos-B gene. Moreover, M-CSF-induced expression of the fos-related gene, fra-1, was delayed compared to that for both c-fos and fos-B. Taken together, the results

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A human T lymphoid cell line, PEER, dies by apoptosis in the presence of PMA and calcium ionophore. A new gene, TINUR, was cloned from apoptotic PEER cells. The expression of the TINUR gene is induced within 1 h after the cross-linking of the T cell Ag receptor complex. TINUR belongs to the NGFI-B/nur77 family of the steroid receptor superfamily and is an orphan receptor. TINUR binds to the same DNA sequence as NGFI-B/nur77. We also

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Human immunodeficiency virus (HIV) often causes latent infection. Transactivation by some DNA viruses has been implicated in inducing HIV-1 replication and pathogenesis. The transactivator (IE-2) gene of the human cytomegalovirus (CMV) can enhance HIV-2 as well as HIV-1 gene expression in vitro. This inducer can act in concert with the HIV-2 tat gene and T-cell activation in enhancing gene expression in human CD4+ lymphocytes. While the HIV-2 and HIV-1 tat genes and T-cell activators apparently employ independent modes of action, the CMV transactivator in combination with the HIV-2 tat or T-cell activators Both HIV-2 and CMV transactivators enhance HIV-2 gene expression by transcriptional activation involving transcript initiation as well as elongation, with CMV transactivator affecting elongation more than the initiation. Deletion mutation analysis of the HIV-2 long terminal repeat (LTR)

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We have demonstrated that native envelope glycoproteins of HIV-1, gp160 can induce activation of the transcription factor, NF-kappa B. The stimulatory effects of gp160 are mediated through the CD4 molecule, since pretreatment with soluble CD4 abrogates its activity. The gp160-induced NF-kappa B complex consists of p65, p50 and c-rel proteins. The stimulatory effect of gp160 on NF-kappa B activation is protein synthesis independent, is dependent upon protein tyrosine phosphorylation, and abrogated by inhibitors of protein kinase C. The gp160-mediated activation of NF-kappa B in CD4 positive T cells

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The nuclear body (NB) is a cellular organelle that is involved in the pathogenesis of acute promyelocytic leukemia and viral infection. The NB is also a target of antibodies in the serum of patients with the autoimmune disease primary biliary cirrhosis. In this study, serum from a patient with primary biliary cirrhosis was used to identify a cDNA encoding a novel component of the NB, a 140-kDa protein designated Sp140. The predicted amino acid sequence of the amino-terminal portion of Sp140 was similar to Sp100, a previously identified NB protein. The carboxyl portion of Sp140 contained a zinc-finger domain and a bromodomain, motifs that are present in proteins regulating gene transcription. High levels of Sp140 mRNA were detected in human spleen and peripheral blood leukocytes, but The level of SP140 mRNA in myeloid precursor cell lines HL60 and NB4 markedly increased in response to chemically induced cellular differentiation. Immunohistochemical techniques were used to demonstrate that SP140 localized to the NB in differentiated HL60 and NB4 cells. The location of Sp140 in the NB, and expression of this gene in cells involved in host defense,

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