Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Resting natural killer (NK) cells express the p75 chain of the IL-2 receptor (IL-2R beta) and most NK cells express the CD2 (erythrocyte rosette) receptor. The cell adhesion molecule, LFA-3, is a natural co-ligand for CD2. Tac antigen (IL-2R alpha), a p55 IL-2R subunit, can be expressed after NK activation and may play a role in IL-2-induced NK proliferation. Little is known of the molecular mechanisms underlying cytokine production in NK cells. We investigated the roles of IL-2R alpha, IL-2R beta, and CD2/LFA-3 in the molecular regulation of NK cell granulocyte/macrophage-colony-stimulating factor (GM-CSF) production. Enriched populations of peripheral blood NK cells were separated into CD16-positive and CD16-negative fractions by flow cytometry; positively selected cells were greater than 97% positive for CD16 (the FcIII receptor for IgG which is present on almost all NK cells), less than 1% positive for the T cell antigen CD3, and did not demonstrate rearrangement of the T cell receptor beta chain gene by Southern blot. NK cell supernatants were harvested after 3-4 d of incubation with 0-100 U/ml IL-2, or after incubation with anti-CD2 (T11(3] MAb and sheep red blood cells (SRBC are a homologue for LFA-3). Parallel cell aliquots were harvested at 3-16 h for transcriptional run-on assays, S1 nuclease assays, and actinomycin D mRNA t1/2 determinations. IL-2-activated NK supernatants contained large amounts of GM-CSF (178 +/- 35 pg/ml) by ELISA as did supernatants from CD2-activated NK cells (T11(3) MAb + SRBC: 212 +/- 42) vs. less than 20 pg/ml for NK cells incubated alone or with either SRBC or T11(3) MAb alone. Sepharose-linked anti-CD3 MAb did not induce GM-CSF release from NK cells. By S1 analysis, both IL-2 and CD2 stimulation markedly augmented GM-CSF mRNA expression but with very different latencies of onset. IL-2R beta MAb inhibited greater than 85% of GM-CSF release from IL-2-activated NK cells and markedly suppressed IL-2-induced GM-CSF mRNA expression, whereas IL-2R alpha MAb even at 2,000-fold molar excess of IL-2 had little effect (less than 10%) on either GM-CSF release or mRNA expression. Run-on assays showed that GM-CSF is constitutively transcribed in NK cells and that IL-2 and CD2-activated cells had a three- to fourfold increased rate of GM-CSF transcription compared to nonstimulated cells. The t1/2 of GM-CSF mRNA in IL-2-activated NK cells was identical to that of unstimulated NK cells (15 min), whereas GM-CSF mRNA t1/2 in CD2-activated NK cells was increased 2.5-fold. We conclude that GM-CSF production in NK cells is regulated by both the IL-2Rbeta and the CD2 receptor but not by IL-2Ralpha, that both transcriptional and posttranscriptional signals act together to modulate the level of GM-CSF mRNA in NK cells, and that the molecular mechanisms underlying NK cell GM-CSF production are dependent in part on differential surface receptor activation.
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PMID:Production of granulocyte/macrophage-colony-stimulating factor by human natural killer cells. Modulation by the p75 subunit of the interleukin 2 receptor and by the CD2 receptor. 167 38

Using a monoclonal antibody to the interleukin 3 (IL-3) receptor (anti-Aic2), we isolated a cDNA (AIC2B) from a mouse mast cell line which is homologous to the previously characterized gene for the IL-3 receptor (AIC2A). This cDNA encodes a polypeptide of 896 amino acid residues and has 91% amino acid sequence identity with the IL-3 receptor. A consensus sequence defining an additional cytokine receptor family is present in this clone. Compared to the AIC2A clone, the AIC2B cDNA encodes a protein with amino acid substitutions, insertions, and deletions dispersed throughout the entire protein. Oligonucleotide probes specific for each cDNA hybridized with different genomic fragments, indicating that the AIC2A and AIC2B proteins are encoded by two distinct genes. Fibroblasts transfected with the AIC2B cDNA expressed the protein at the cell surface as determined by binding with the anti-Aic2 antibody but did not bind IL-3 or other cytokines, including IL-2, IL-4, granulocyte-macrophage colony-stimulating factor, erythropoietin, and IL-9 (p40) at concentrations between 1 and 10 nM. An S1 nuclease protection assay was used to discriminate between the AIC2A and AIC2B transcripts. We found that the AIC2B gene was coexpressed with the AIC2A gene. These results suggest a potential involvement of AIC2B in cytokine signal transduction.
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PMID:Cloning and expression of a gene encoding an interleukin 3 receptor-like protein: identification of another member of the cytokine receptor gene family. 169 79

Cultured human keratinocytes have been shown to produce IL-1 alpha and beta mRNA and protein. IL-1 biological activity has been identified in normal human epidermis; in vitro, most biologically active IL-1 resides in a cell-associated compartment. The potential for autocrine effects of IL-1 on human keratinocytes was assessed by measurement of keratinocyte IL-1 receptors. Both high- and low-affinity cell surface receptors that bound recombinant (r) IL-1 alpha and beta with comparable affinities could be identified on cultured human keratinocytes, using 125I-labeled rIL-1. Chemical crosslinking experiments identified a cell surface molecule of roughly 72,500 Mr that bound 125I-labeled IL-1, similar to the molecular weight of previously described IL-1 receptors on fibroblasts, B cells, and T cells. To assess the biological consequences of keratinocyte IL-1 binding, granulocyte-macrophage colony-stimulating factor (GM-CSF) gene expression was measured. The addition of exogenous rIL-1 alpha led to a dose-dependent increase in the accumulation of GM-CSF mRNA, as measured by a sensitive and specific S1 nuclease assay. This increase in mRNA was reflected in a marked increase in GM-CSF biological activity as measured by proliferation of blast cells from chronic myelogenous leukemia patients. The biological activity was completely inhibitable by an antibody to human rGM-CSF. GM-CSF activates mature neutrophils and macrophages and appears to enhance the efficiency of Langerhans cell antigen presentation to T cells. Release of IL-1 from injured or activated keratinocytes may lead to enhanced epidermal GM-CSF gene expression via an autocrine mechanism, thus enhancing local host defense.
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PMID:Interleukin 1 binds to specific receptors on human keratinocytes and induces granulocyte macrophage colony-stimulating factor mRNA and protein. A potential autocrine role for interleukin 1 in epidermis. 246 May 4

We have isolated cDNA clones encoding human IL-3 from libraries constructed in a modified pcD mammalian expression vector by using mRNA prepared from activated human T cell clones. Amino acid sequence of human IL-3 deduced from DNA sequence of these cDNA clones agrees with that predicted from genomic sequence except at amino acid position 27. Northern blotting analysis and S1 nuclease analysis show that almost all activated T cell clones express IL-3 mRNA with kinetics similar to that observed in mouse T cell clones. However, striking difference was found in the level of granulocyte-macrophage-CSF and IL-3 mRNA expressed in activated human T cells. In contrast to mouse T cell clones, granulocyte-macrophage-CSF mRNA is expressed at least two orders of magnitude more abundant than IL-3 mRNA. Yeast Saccharomyces cerevisiae carrying human IL-3 cDNA fused downstream to alpha-factor leader sequence expressed and secreted biologically active IL-3. Several different rat anti-peptide antisera have been used to confirm the presence of human rIL-3 immunochemically. The immunoreactive human IL-3 expressed in transiently transfected COS7 cells or in yeast was observed to be heterogeneous. Human rIL-3 expressed in COS7 cells has multipotential CSF activity in semisolid cultures of bone marrow cells, and selectively induced the proliferation of My-10+ marrow or cord blood cells in liquid cultures.
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PMID:Isolation and characterization of an expressible cDNA encoding human IL-3. Induction of IL-3 mRNA in human T cell clones. 312 63

The expression of cytokine genes in cultures of human peripheral blood mononuclear cells (PBMC) stimulated with mannoprotein constituents (MP) of Candida albicans has been studied by means of S1 nuclease mapping analysis, polymerase chain reaction, and enzyme-linked immunosorbent assay. MP induced early, consistent, and long-lasting production of interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha, and IL-6 mRNAs. Similar results were obtained when the same PBMC cultures were stimulated with the purified protein derivative (PPD) from Mycobacterium tuberculosis or with IL-2, although lower levels of IL-6 mRNA were detected in IL-2-stimulated cells than in MP- or PPD-stimulated cells. MP, PPD, and IL-2 induced appreciable levels of granulocyte-macrophage colony-stimulating factor and gamma interferon, but only MP and PPD were able to induce IL-2 mRNA. MP were unable to stimulate a consistent expression of the genes encoding for IL-4, IL-5, and IL-10, while low, sometimes barely detectable levels of these cytokine mRNAs were observed in PPD- or IL-2-stimulated PBMC cultures. When protein synthesis of MP-stimulated PBMC was inhibited by cycloheximide, a superinduction of mRNAs for IL-4 and IL-10 and, more markedly, gamma interferon was observed. Overall, these results highlight the powerful, selective induction of cytokine gene expression by MP constituents of C. albicans in human PBMC cultures, thus providing some functional clues to explain the efficient state of the anticandidal response in normal human subjects.
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PMID:Cytokine gene expression in human peripheral blood mononuclear cells stimulated by mannoprotein constituents from Candida albicans. 840 99

We analyzed the effect of several growth factors and cytokines on the expression of amyloid beta protein precursor (APP) mRNAs in cultured mouse neuronal and glial cells. In neuronal cultures from embryonic day-15 brain. Northern blotting revealed that APP mRNAs increased by 1.3- to 2.6-fold when treated with nerve growth factor, basic fibroblast growth factor, interleukin 1, interleukin 2, interleukin 3, interleukin 6 or granulocyte-macrophage colony-stimulating factor but not with tumor necrosis factor alpha. An S1 nuclease protection assay revealed that the enhanced APP mRNA in neuronal cultures was exclusively APP695 mRNA. On the other hand, astrocyte-enriched cultures prepared from postnatal day-2 brain did not show any significant alteration among these factors. We conclude that certain growth factors and cytokines could enhance APP 695 mRNA expression in neurons in vitro.
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PMID:Effect of growth factors and cytokines on expression of amyloid beta protein precursor mRNAs in cultured neural cells. 847 81

We previously noted that the initial receptor by which murine osteoclast precursors bind matrix is the integrin alphav beta5 and that granulocyte-macrophage colony-stimulating factor (GM-CSF) decreases expression of this heterodimer by suppressing transcription of the beta5 gene. We herein report cloning of the beta5 integrin gene promoter and identification of a GM-CSF-responsive sequence. A 13-kilobase (kb) genomic fragment containing part of the beta5 gene was isolated by screening a mouse genomic library with a probe derived from the most 5'-end of a murine beta5 cDNA. A combination of primer extension and S1 nuclease studies identifies two transcriptional start sites, with the major one designated +1. A 1-kb subclone containing sequence -875 to + 110 is transcriptionally active in a murine myeloid cell line. This 1-kb fragment contains consensus binding sequences for basal (Sp1), lineage-specific (PU.1), and regulatable (signal transducer and activator of transcription) transcription factors. Reflecting our earlier findings, promoter activity is repressed in transfected myeloid cells treated with GM-CSF. Using deletion mutants, we localized a 109-base pair (bp) promoter region responsible for GM-CSF-inhibited beta5 transcription. We further identified a 19-bp sequence within the 109-bp region that binds GM-CSF-induced nuclear proteins by gel shift/competition assays. Mutation of the 19-bp sequence not only ablates its capacity to bind nuclear proteins from GM-CSF-treated cells, in vitro, but the same mutation, when introduced in the 1-kb promoter, abolishes its ability to respond to GM-CSF treatment. Northern analysis demonstrates that cycloheximide treatment abrogates the capacity of GM-CSF to decrease beta5 mRNA levels. In summary, we have identified a 19-bp cis-element mediating GM-CSF-induced down-regulation of beta5 by a mechanism requiring protein synthesis.
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PMID:Cloning of the murine beta5 integrin subunit promoter. Identification of a novel sequence mediating granulocyte-macrophage colony-stimulating factor-dependent repression of beta5 integrin gene transcription. 988 May 8