Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To understand the mechanisms involved in dsRNA-induced gene expression, we analyzed the poly(I/C)-induced transcription of the IFN-inducible chemokine gene IP-10 using the GRE cell line in which type I IFN genes have been deleted. Accumulation of IP-10 mRNA in GRE cells was more strongly stimulated by treatment with dsRNA than by IFN-alpha or IFN-gamma and was independent of protein synthesis. This same pattern of response was produced when GRE cells were transiently transfected with a plasmid containing 243 bases of sequence from the promoter of the murine IP-10 gene linked to the chloramphenicol acetyltransferase reporter gene. Deletion- and site-specific mutagenesis of the 243 base pair fragment indicated that an ISRE located between residues -204 and -228 was a primary target site for the action of dsRNA on this promoter. This was confirmed by results showing that two copies of this ISRE tandemly arrayed in front of the thymidine kinase promoter were able to mediate reporter gene transcription in dsRNA-stimulated cells. At least one of the two NF kappa B binding sites present in the 243 base pair IP-10 promoter is also necessary for response to dsRNA; mutation of both sites eliminates promoter activity. Thus the ISRE and one NF kappa B site cooperate to produce transcriptional response to dsRNA.
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PMID:Interferon-stimulated response element and NF kappa B sites cooperate to regulate double-stranded RNA-induced transcription of the IP-10 gene. 789 55

Human neutrophils are highly responsive to the chemokine interleukin-8 (IL-8) owing to high levels of expression of two related receptors encoded by the single copy genes il8ra and il8rb located on chromosome 2q34-q35. To identify nuclear factors that regulate the expression of IL-8 receptors, we have first defined the organization of both genes and characterized their functional promoters. il8ra and il8rb span approximately 4 and 12 kilobase pairs of genomic DNA, respectively. In both cases, the open reading frame resides on a single exon. In contrast, the 5'-untranslated regions are more complex. For il8ra, it is formed from two exons, whereas for il8rb, seven distinct neutrophil mRNAs are formed by alternative splicing of 11 exons. One of the splice variants, designated IL8RB3, is the predominant form for il8rb. Two equally abundant mRNAs for il8ra, 2.0 and 2.4 kilobases in length, are expressed in neutrophils and arise from usage of two alternative polyadenylation signals. Primer extension analysis identified two major transcription start points for il8ra and 11 for il8rb. Regions extending 300 base pairs (bp) upstream from exon 1 of il8ra and 81 bp upstream from exon 3 of il8rb have limited sequence similarity but had strong constitutive promoter activity when cloned upstream from a chloramphenicol acetyltransferase-encoding reporter gene and transiently transfected into surrogate myeloid (HL-60, and U-937) and lymphoid (Jurkat) cell lines. Neither of these regions has sequences corresponding to classic promoter elements. In contrast, a region 643 base pairs upstream from exon 1 of il8rb had relatively low levels of constitutive promoter activity in all three cell environments, and a conserved TATA element is located 47 bp upstream of the 5'-end of exon 1. Thus, despite marked differences in the complexity of their genomic organization, il8ra and il8rb encode products that are similar in structure, function, and the major cell type of expression.
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PMID:Comparison of the genomic organization and promoter function for human interleukin-8 receptors A and B. 792 58

T-cell activation gene 3 (TCA3) encodes a beta-chemokine that is transcriptionally regulated in mast cells; the gene has a functional NF-kappaB element at positions -194 to -185. The 5'-flanking region of this gene is also known to have a negative regulatory region between -2057 and -1342. To characterize the negative regulatory elements (NREs), this region was sequenced and then digested by HindIII enzyme into two fragments, NRE-1 (-2057 to -1493) and NRE-2 (-1492 to -1342). Both NRE-1 and NRE-2 in the 5'-3' orientation inhibited chloramphenicol acetyltransferase (CAT)-protein synthesis by a TCA3-CAT construct transfected into mast cells that were then activated. Only NRE-1 inhibited CAT-protein synthesis in the 3'-5' orientation. Further deletion of the 5' region of NRE-1 partially abolished the inhibitory activity. Both NRE-1 and NRE-2 inhibited the activity of a CD20-CAT construct independent of cell activation. Electrophoretic mobility shift assays showed DNA-protein complex formation with subsequences (CCCCCATTCT) of NRE-1 (NRE-1a) and (CCATGA) of NRE-2 (NRE-2b). NRE-1a appears to be novel. NRE-2b is identical with a putative silencer motif in the alphaIIb integrin gene. Site-directed mutagenesis demonstrated that both NRE-1a and NRE-2b are important in the negative regulation of TCA3 promoter activity. In vivo ligation-mediated PCR footprinting of the NRE-2 region revealed protection between -1372 and -1354, which contains NRE-2b. The data thus demonstrate identity of a silencer motif, here termed NRE-2b, in both the alphaIIb integrin gene and the TCA3, and that this silencer region in mast cells is functional both in vivo and in vitro. Further, evidence is presented that the promoter for TCA3 contains a novel silencer motif, termed NRE-1a, characterized by a CT-rich sequence.
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PMID:Two different negative regulatory elements control the transcription of T-cell activation gene 3 in activated mast cells. 916 46

The C-C chemokines RANTES, MIP-1alpha, and MIP-1beta have been characterized as constituents of an HIV- and SIV-suppressive factor released by CD8+ cells. Furthermore, it has been demonstrated that chemokine receptors cooperate in HIV entry. However, these proteins are also known to have an effect on multiple intracellular signaling cascades that may affect the process of transcription. In the present study we demonstrate that treatment of CD4+ T cells with these chemokines or with cell supernatants from HTLV-I-immortalized CD8+ T cells results in significant reduction in the abundance of HIV-1-specific RNA as analyzed by Northern blot hybridization. To examine the possibility that such suppressive factors may inhibit HIV RNA transcription, we studied the effect of RANTES, the most effective HIV-suppressive chemokine, on basal and Tat-induced HIV-directed LTR expression of a reporter gene. Neither recombinant RANTES nor conditioned medium from CD8+ cells significantly altered HIV-1 LTR-directed chloramphenicol acetyltransferase expression in either transiently or stably transfected CD4+ T cell lines, either in the presence or in the absence of Tat. These results suggest that C-C chemokines do not inhibit viral RNA transcription.
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PMID:C-C chemokine RANTES and HIV long terminal repeat-driven gene expression. 935 55

mRNA transcribed from the mouse KC chemokine gene accumulated to significantly higher levels in multiple cell types after treatment with interleukin 1alpha (IL-1alpha) as compared with tumor necrosis factor-alpha (TNFalpha). Although TNFalpha and IL-1alpha both signaled the activation of nuclear factor kappaB and enhanced transcription of the KC gene with equal potency, only IL-1alpha treatment resulted in stabilization of KC mRNA. Nucleotide sequences that confer sensitivity for IL-1alpha-mediated mRNA stabilization were identified within the 5'- and 3'-untranslated regions (UTRs) of KC mRNA using transient transfection of chimeric plasmids containing specific portions of KC mRNA linked to the chloramphenicol acetyltransferase (CAT) gene. When plasmids containing either the 3'- or 5'-UTR of KC mRNA were used, the half-life of CAT mRNA was unaltered either in untreated or IL-1alpha-stimulated cells. In contrast, CAT mRNA transcribed from plasmids that contained both the 5'- and 3'-UTRs of the KC mRNA decayed more rapidly than control CAT mRNA, and this enhanced decay was prevented in cells treated with IL-1alpha. A cluster of four overlapping AUUUA motifs within the 3'-UTR was required, whereas the 5'-UTR region exhibited orientation dependence. These findings indicate that cooperative function of the two nucleotide sequences involves a distinct signaling pathway used by IL-1alpha but not TNFalpha.
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PMID:Interleukin-1-mediated stabilization of mouse KC mRNA depends on sequences in both 5'- and 3'-untranslated regions. 1077

Oxidants and inflammatory mediators such as tumour necrosis factor-alpha (TNF-alpha) activate transcription factors such as NF-kappa B. Interleukin-8 (IL-8) is a ubiquitous inflammatory chemokine that mediates a multitude of inflammatory events in the lung. Ergothioneine is a naturally occurring thiol compound, which possesses antioxidant property. The aim of this study was to determine whether ergothioneine can inhibit the hydrogen peroxide (H(2)O(2))- and TNF-alpha-mediated activation of NF-kappa B and the release of IL-8 in human alveolar epithelial cells (A549). Treatment of A549 cells with H(2)O(2) (100 microM) and TNF-alpha (10 ng/ml) significantly increased NF-kappa B activation using a reporter assay. Ergothioneine inhibited both H(2)O(2)- and TNF-alpha-mediated activation of NF-kappa B. Both H(2)O(2) and TNF-alpha significantly increased IL-8 release, which was inhibited by pre-treatment of A549 cells with ergothioneine compared to the control untreated cells. Ergothioneine also abolished the transcriptional activation of IL-8 in an IL-8-chloramphenicol acetyltransferase (CAT) reporter system, transfected into A549 cells. This indicates a molecular mechanism for the anti-inflammatory effects of ergothioneine.
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PMID:Ergothioneine inhibits oxidative stress- and TNF-alpha-induced NF-kappa B activation and interleukin-8 release in alveolar epithelial cells. 1264 50