Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lipoxygenase pathway has been implicated in the growth, migration, and contraction of vascular smooth muscle cells (VSMCs). However, the precise type of lipoxygenase present in the vascular wall has not been characterized. In this study, we used a specific reverse-transcriptase polymerase chain reaction method with 2 sets of specific primers on total RNA and polyA (+)RNA of normal human VSMCs prepared from umbilical artery. Two forms of platelet-type 12-lipoxygenase mRNA were present in human VSMCs: the already published form cloned from human erythroleukemia cells and a variant form of platelet-type 12-lipoxygenase, which includes 2 additional sequences consistent with the 2 introns (D and E). This novel form of 12-lipoxygenase poly A (+)RNA was downregulated by lipopolysaccharide (10 ug/ml) and upregulated by epidermal growth factor (100 ng/ml) but was not affected by angiotensin II (10(-7) mol/l). We developed a rabbit anti-human platelet-type 12-lipoxygenase polyclonal antibody directed against a 24-amino acid peptide encoded within exon 4. Western immunoblotting of protein extracted from VSMCs and umbilical artery and platelet extract with this antibody showed a coordinate 110-kDa protein and the already-described 70-kDa band detected in platelets and cord homogenate. Another 120-kDa protein was consistently detected in cord extracts but not in platelet or VSMC homogenates. The immunohistochemistry study performed with the same antibody showed extensive cytoplasmic staining of VSMCs. The specific role of these different forms of platelet-type 12-lipoxygenase is subject to further investigation.
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PMID:A novel form of platelet-type 12-lipoxygenase mRNA in human vascular smooth muscle cells. 1164

In this work, we characterize genes in Mycobacterium tuberculosis that are regulated by IdeR (iron-dependent regulator), an iron-responsive DNA-binding protein of the DtxR family that has been shown to regulate iron acquisition in Mycobacterium smegmatis. To identify some of the genes that constitute the IdeR regulon, we searched the M. tuberculosis genome for promoter regions containing the consensus IdeR/DxR binding sequence. Genes preceded by IdeR boxes included a set encoding proteins necessary for iron acquisition, such as the biosynthesis of siderophores (mbtA, mbtB, mbtI), aromatic amino acids (pheA, hisE, hisB-like) and others annotated to be involved in the synthesis of iron-storage proteins (bfrA, bfrB). Some putative IdeR-regulated genes identified in this search encoded proteins predicted to be engaged in the biosynthesis of lipopolysaccharide (LPS)-like molecules (rv3402c), lipids (acpP) and peptidoglycan (murB). We analysed four promoter regions containing putative IdeR boxes, mbtA-mbtB, mbI, rv3402c and bfrA-bfd, for interaction with IdeR and for iron-dependent expression. Gel retardation experiments and DNase footprinting analyses with purified IdeR showed that IdeR binds to these IdeR boxes in vitro. Analysis of the promoters by primer extension indicated that the IdeR boxes are located near the -10 position of each promoter, suggesting that IdeR acts as a transcriptional repressor by blocking RNA polymerase binding. Using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) coupled to molecular beacons, we showed that mRNA levels of mbtA, mbtB, mbtI, rv3402c and bfd are induced 14- to 49-fold in cultures of M. tuberculosis starved for iron, whereas mRNA levels of bfrA decreased about threefold. We present evidence that IdeR not only acts as a transcriptional repressor but also functions as an activator of bfrA. Three of the IdeR- and iron-repressed genes, mbtB, mbtI and rv3402c, were induced during M. tuberculosis infection of human THP-1 macrophages.
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PMID:The Mycobacterium tuberculosis IdeR is a dual functional regulator that controls transcription of genes involved in iron acquisition, iron storage and survival in macrophages. 1172 47

Paneth cells in small intestinal crypts secrete microbicidal alpha-defensins in response to bacteria and bacterial antigens (Ayabe, T., Satchell, D. P., Wilson, C. L., Parks, W. C., Selsted, M. E., and Ouellette, A. J. (2000) Nat. Immunol. 1, 113- 38). We now report that the Ca(2+)-activated K(+) channel mIKCa1 modulates mouse Paneth cell secretion. mIKCa1 cDNA clones identified in a mouse small intestinal crypt library by hybridization to human IKCa1 cDNA probes were isolated, and DNA sequence analysis showed that they were identical to mIKCa1 cDNAs isolated from erythroid cells and liver. The genomic organization was found to be conserved between mouse and human IKCa1 as shown by comparisons of the respective cDNA and genomic sequences. Reverse transcriptase-PCR experiments using nested primers amplified mIKCa1 from the lower half of bisected crypts and from single Paneth cells, but not from the upper half of bisected crypts, villus epithelium, or undifferentiated crypt epithelial cells, suggesting a lineage-specific role for mIKCa1 in mouse small bowel epithelium. The cloned mIKCa1 channel was calcium-activated and was blocked by ten structurally diverse peptide and nonpeptide inhibitors with potencies spanning 9 orders of magnitude and indistinguishable from that of the human homologue. Consistent with channel blockade, charybdotoxin, clotrimazole, and the highly selective IKCa1 inhibitors, TRAM-34 and TRAM-39, inhibited (approximately 50%) Paneth cell secretion stimulated by bacteria or bacterial lipopolysaccharide, measured both as bactericidal activity and secreted cryptdin protein, but the inactive analog, TRAM-7, did not block secretion. These results demonstrate that mIKCa1 is modulator of Paneth cell alpha-defensin secretion and disclose an involvement in mucosal defense of the intestinal epithelium against ingested bacterial pathogens.
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PMID:Modulation of mouse Paneth cell alpha-defensin secretion by mIKCa1, a Ca2+-activated, intermediate conductance potassium channel. 1172 75

Current knowledge implicates pleural mesothelial cells as mainly responsible for inflammatory responses in the pleural space. However, a vast body of recent evidence underscores the important role of fibroblasts in the process of inflammation in several types of tissues. We hypothesize that HPFBs (human pleural fibroblasts) play an important role in pleural responses and also when activated by bacterial endotoxin LPS (lipopolysaccharide), IL-1 beta (interleukin-1 beta), or TNF-alpha (tumor necrosis factor-alpha) release of C-C and C-X-C chemokines-specifically, MCP-1 and IL-8. Our results show that pleural fluid-isolated human fibroblasts release IL-8 and MCP-1 upon stimulation with IL-1 beta, TNF-alpha, and LPS in both a concentration- and time-dependent manner. RT-PCR (reverse-transcriptase-polymerase chain reaction) studies have also confirmed IL-8- and MCP-1-specific mRNA expression in activated pleural fibroblasts. On the time-dependent response curve, IL-8 was found in maximum concentrations at 144 hr, whereas MCP-1 continued to increase even after 196 hr following stimulation. IL-1 beta induced the maximum release of IL-8 (800-fold) and MCP-1 (164-fold), as compared to the controls. TNF-alpha induced a 95-fold increase in IL-8 and an 84-fold increase in MCP-1 levels, as compared to the controls. Collectively, our results show that human pleural fibroblasts contribute to the inflammatory cascade in the pleural space.
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PMID:Inflammatory cytokines mediate C-C (monocyte chemotactic protein 1) and C-X-C (interleukin 8) chemokine expression in human pleural fibroblasts. 1198 90

The repair of an injured bronchial epithelial cell (BEC) monolayer requires proliferation and migration of BECs into the injured area. We hypothesized that BEC monolayer injury results in monocyte chemoattractant protein-1 (MCP-1) production, which initiates the repair process. BECs (BEAS-2B from ATCC) were utilized in this study. MCP-1 interacts with CCR2B receptor (CCR2B), resulting in cell proliferation, haptotaxis, and healing of the monolayer. Reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to verify the presence of CCR2B. CCR2B was not merely present but also inducible by interleukin-2 (IL-2) and lipopolysaccharide (LPS). We demonstrated by immunohistochemistry that BECs express MCP-1 after injury and that receptor expression can be regulated by exposure to IL-2 and LPS. Haptotactic migration of cells was enhanced in the presence of MCP-1 and reduced in the presence of CCR2B antibody. This enhanced or depressed ability of the BECs to perform haptotactic migration was shown to be statistically significant (P < 0.05) when compared to controls. Finally, BECs proliferate in response to MCP-1 as proven by electric cell-substrate impedance sensing (ECIS) technology. MCP-1-specific antibodies were shown to neutralize the MCP-1-mediated BEC proliferation. This cascade of events following injury to the bronchial epithelium may provide insight into the mechanism of the repair process.
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PMID:Induction of MCP-1 expression in airway epithelial cells: role of CCR2 receptor in airway epithelial injury. 1207 56

Regulated gene expression is a complex process achieved through the function of multiple protein factors acting in concert at a given promoter. The transcription factor TFIID is a central component of the machinery regulating mRNA synthesis by RNA polymerase II. This large multiprotein complex is composed of the TATA box binding protein (TBP) and several TBP-associated factors (TAF(II)s). The recent discovery of multiple TBP-related factors and tissue-specific TAF(II)s suggests the existence of specialized TFIID complexes that likely play a critical role in regulating transcription in a gene- and tissue-specific manner. The tissue-selective factor TAF(II)105 was originally identified as a component of TFIID derived from a human B-cell line. In this report we demonstrate the specific induction of TAF(II)105 in cultured B cells in response to bacterial lipopolysaccharide (LPS). To examine the in vivo role of TAF(II)105, we have generated TAF(II)105-null mice by homologous recombination. Here we show that B-lymphocyte development is largely unaffected by the absence of TAF(II)105. TAF(II)105-null B cells can proliferate in response to LPS, produce relatively normal levels of resting antibodies, and can mount an immune response by producing antigen-specific antibodies in response to immunization. Taken together, we conclude that the function of TAF(II)105 in B cells is likely redundant with the function of other TAF(II)105-related cellular proteins.
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PMID:Redundant role of tissue-selective TAF(II)105 in B lymphocytes. 1219 54

The human immunodeficiency virus type 1 (HIV-1) Tat protein is essential for viral replication and stimulates transcription of the integrated provirus by recruiting the kinase complex TAK/P-TEFb, composed of cyclin T1 (CycT1) and Cdk9, to the viral TAR RNA element. TAK/P-TEFb phosphorylates the RNA polymerase II complex and stimulates transcriptional elongation. In this report, we investigated the regulation of TAK/P-TEFb in primary human macrophages, a major target cell of HIV infection. While Cdk9 levels remained constant, CycT1 protein expression in freshly isolated monocytes was very low, increased early during macrophage differentiation, and, unexpectedly, decreased to very low levels after about 1 week in culture. The kinase activity of TAK/P-TEFb paralleled the changes in CycT1 protein expression. RNA analysis indicated that the transient induction of CycT1 protein expression involves a posttranscriptional mechanism. In transient transfection assays, the ability of Tat to transactivate the HIV long terminal repeat (LTR) in the late differentiated macrophages was greatly diminished relative to its ability to transactivate the HIV LTR in early differentiated cells, strongly suggesting that CycT1 is limiting for Tat function in late differentiated macrophages. Interestingly, lipopolysaccharide, a component of the cell wall of gram-negative bacteria, reinduced CycT1 expression late in macrophage differentiation. These results raise the possibility that regulation of CycT1 expression may be involved in establishing latent infection in macrophages and that opportunistic infection may reactivate the virus by inducing CycT1 expression.
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PMID:Transient induction of cyclin T1 during human macrophage differentiation regulates human immunodeficiency virus type 1 Tat transactivation function. 1236

Oestrogen receptor (ER) regulation of gene transcription in neurosecretory and pituitary cells has been proposed as an important mechanism for increased hypothalamic-pituitary-adrenal (HPA) axis responses in females of several mammalian species, including humans. Inbred female Fischer (F344/N) and Lewis (LEW/N) rats have similar oestrogen levels, although Fischer rats exhibit hyper- and Lewis rats hypo-HPA axis responses. The blunted HPA axis response of Lewis rats has been associated with their blunted hypothalamic corticotropin releasing hormone (CRH) expression. To determine if the female CRH expression deficiency in Lewis rats is associated with defective ER expression and regulation, hypothalamic paraventricular nucleus (PVN) transcript levels of CRH and ER were determined under basal conditions and after immune challenge. Microdissected PVN were obtained from control and lipopolysaccharide (LPS) treated Lewis and Fischer rats and CRH, ERalpha and beta mRNA levels were determined by semiquantitative reverse-transcriptase-polymerase chain reaction. In addition, ERalpha and beta protein levels were determined by semiquantitative Western blots. ERalpha and beta mRNA and protein levels in the PVN of control Fischer rats were significantly higher than in control Lewis rats. ERalpha and beta mRNA and protein levels in Fischer rats were reduced by LPS administration at the time of maximal CRH mRNA levels but did not change in Lewis rats, an effect independent of oestrogen levels. These data indicate that defective neuroendocrine HPA axis responses are associated with defective ER expression and regulation in Lewis PVN despite oestrogen concentrations.
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PMID:Lipopolysaccharide-induced oestrogen receptor regulation in the paraventricular hypothalamic nucleus of lewis and Fischer rats. 1242 37

KE-758, an active metabolite of KE-298, is a novel sulfhydryl antirheumatic drug. We analyzed the effect of KE-758 on tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta production by a human monocytes cell line (THP-1 cells), stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). We compared the effects with other thiol-modifying antirheumatic drugs such as D-penicillamine, bucillamine and auranofin. THP-1 cells were treated with IFN-gamma for 16 h and were then exposed to LPS for an additional 6 h (for TNF-alpha detection) or 24 h (for IL-1 beta detection). The amounts of TNF-alpha and IL-1 beta in culture supernatants were measured using enzyme-linked immunosorbent assay. KE-758 and auranofin but not D-penicillamine and bucillamine significantly suppressed both TNF-alpha and IL-1 beta. Auranofin suppressed IL-1 beta production by reducing cellular viability. Reverse transcriptase-polymerase chain reaction analysis revealed that the suppressive effect of KE-758 is based on the inhibition of messenger ribonucleic acid expression of TNF-alpha and IL-1 beta. KE-758 had no effect on p75 and p55 soluble TNF receptor production in IFN-gamma and LPS-stimulated THP-1 cells. Thus, KE-758 inhibits both TNF-alpha and IL-1 beta production and its antirheumatic profile is apparently distinct from that of D-penicillamine, bucillamine and auranofin.
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PMID:KE-758, an active metabolite of the new anti-rheumatic drug KE-298, suppresses production of tumor necrosis factor-alpha and interleukin-1 beta in THP-1, a human monocyte cell line. 1263 95

The genome of the lytic Pseudomonas putida bacteriophage gh-1 is linear double-stranded DNA containing 37,359 bp with 216-bp direct terminal repeats. Like other members of the T7 group, the gh-1 genome contains regions of high homology to T7 interspersed with nonhomologous regions that contain small open reading frames of unknown function. The genome shares 31 genes in common with other members of the T7 group, including RNA polymerase, and an additional 12 unique putative genes. A major difference between gh-1 and other members of this group is the absence of any open reading frames between the left direct terminal repeat and gene 1. Sequence analysis of the gh-1 genome also revealed the presence of 10 putative phage promoters with a consensus sequence similar to the promoters of T3 and phiYeO3-12 (consensus: TAAAAACCCTCACTRTGGCHSCM). P. putida mutants resistant to gh-1 were demonstrated to have an altered lipopolysaccharide structure, indicating that members of this group use lipopolysaccharide as their cellular receptor.
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PMID:The complete genomic sequence of lytic bacteriophage gh-1 infecting Pseudomonas putida--evidence for close relationship to the T7 group. 1284 20


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