Search results for "Reporter"
showing 10 items of 166 documents
Differential Regulation of CCL22 Gene Expression in Murine Dendritic Cells and B Cells
2005
Abstract The activated T cell-attracting CC chemokine CCL22 is expressed by stimulated B cells and mature dendritic cells (DC). We have cloned and sequenced the complete mouse gene, including 4 kb of the 5′-flanking promoter region, and detected two distinct sites for initiation of transcription by 5′-RACE. Reporter gene assays indicate that the promoter reflects the specificity of the endogenous gene. Within the proximal promoter region, we identified potential binding sites for NF-κB, Ikaros, and a putative GC box. All three regions bind proteins. The NF-κB site was shown to specifically bind NF-κB subunits p50 and p65 from nuclear extracts of LPS-stimulated B cells, B cell line A20/2J, T…
Transcriptional Regulation of Human CYP3A4 Basal Expression by CCAAT Enhancer-Binding Protein α and Hepatocyte Nuclear Factor-3γ
2003
Cytochrome P450 3A4 (CYP3A4) is involved in the metabolism of more than 50% of currently used therapeutic drugs, yet the mechanisms that control CYP3A4 basal expression in liver are poorly understood. Several putative binding sites for CCAAT/enhancer-binding protein (C/EBP) and hepatic nuclear factor 3 (HNF-3) were found by computer analysis in CYP3A4 promoter. The use of reporter gene assays, electrophoretic mobility shift assays, and site-directed mutagenesis revealed that one proximal and two distal C/EBP alpha binding sites are essential sites for the trans-activation of CYP3A4 promoter. No trans-activation was found in similar reporter gene experiments with a HNF-3 gamma expression vec…
Physiological activation of the IgH 3' enhancer in B lineage cells is not blocked by Pax-5.
1996
The mouse 3' enhancer contains a high-affinity binding site for the paired box protein Pax-5. Here, we demonstrate by genomic footprinting that the rat 3' enhancer contains a low-affinity binding site for Pax-5, which is occupied in activated splenic B cells. Thus, binding of Pax-5 to the IgH 3' enhancer appears to be evolutionarily conserved in rodents. Analysis of Pax-5 expression in primary B cells demonstrates that Pax-5 remains expressed after 4 days of lipopolysaccharide (LPS) induction, but is down-regulated in 5-day stimulated cells. Similarly, the expression of Pax-5 is down-regulated in vivo in activated large splenocytes, in contrast to small resting cells. Multimerization of the…
The yopJ locus is required for Yersinia-mediated inhibition of NF-kappaB activation and cytokine expression: YopJ contains a eukaryotic SH2-like doma…
1998
Upon exposure to bacteria, eukaryotic cells activate signalling pathways that result in the increased expression of several defence-related genes. Here, we report that the yopJ locus of the enteropathogen Yersinia pseudotuberculosis encodes a protein that inhibits the activation of NF-kappaB transcription factors by a mechanism(s), which prevents the phosphorylation and subsequent degradation of the inhibitor protein IkappaB. Consequently, eukaryotic cells infected with YopJ-expressing Yersinia become impaired in NF-kappaB-dependent cytokine expression. In addition, the blockage of inducible cytokine production coincides with yopJ-dependent induction of apoptosis. Interestingly, the YopJ pr…
Ionizing radiation-induced E-selectin gene expression and tumor cell adhesion is inhibited by lovastatin and all-trans retinoic acid
2004
E-selectin mediated tumor cell adhesion plays an important role in metastasis. Here we show that ionizing radiation (IR) induces E-selectin gene and protein expression in human endothelial cells at therapeutically relevant dose level. E-selectin expression is accompanied by an increase in the adhesion of human colon carcinoma cells to primary human umbilical vein endothelial cells (HUVEC). The HMG-CoA reductase inhibitor lovastatin impairs IR-stimulated E-selectin expression as analyzed at the level of the protein, mRNA and promoter. Inactivation of Rho GTPases either by use of Clostridium difficile toxin A or by co-expression of dominant-negative Rho blocked IR-induced E-selectin gene indu…
The Arabidopsis Copper Transporter COPT1 Functions in Root Elongation and Pollen Development
2004
Copper plays a dual role in aerobic organisms, as both an essential and a potentially toxic element. To ensure copper availability while avoiding its toxic effects, organisms have developed complex homeostatic networks to control copper uptake, distribution, and utilization. In eukaryotes, including yeasts and mammals, high affinity copper uptake is mediated by the Ctr family of copper transporters. This work is the first report on the physiological function of copper transport in Arabidopsis thaliana. We have studied the expression pattern of COPT1 in transgenic plants expressing a reporter gene under the control of the COPT1 promoter. The reporter gene is highly expressed in embryos, tric…
Expression of a reporter gene is reduced by a ribozyme in transgenic plants
1994
A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentration…
von Hippel-Lindau Protein-Mediated Repression of Tumor Necrosis Factor Alpha Translation Revealed through Use of cDNA Arrays
2003
Based on evidence that the von Hippel-Lindau (VHL) tumor suppressor protein is associated with polysomes and interacts with translation regulatory factors, we set out to investigate the potential influence of pVHL on protein translation. To this end, renal cell carcinoma (RCC) cells that either lacked pVHL or expressed pVHL through stable transfection were used to prepare RNA from cytosolic (unbound) and polysome-bound fractions. Hybridization of cDNA arrays using RNA from each fraction revealed a subset of transcripts whose abundance in polysomes decreased when pVHL function was restored. The tumor necrosis factor alpha (TNF-alpha) mRNA was identified as one of the transcripts that prefere…
Specific sequence elements in the 5′ untranslated regions of rbcL and atpB gene mRNAs stabilize transcripts in the chloroplast of Chlamydomonas reinh…
2001
Using a series of point mutations in chimeric reporter gene constructs consisting of the 5' regions of the Chlamydomonas chloroplast rbcL or atpB genes fused 5' to the coding sequence of the bacterial uidA (GUS) gene, RNA-stabilizing sequence elements were identified in vivo in the 5' untranslated regions (5' UTRs) of transcripts of the chloroplast genes rbcL and atpB in Chlamydomonas reinhardtii. In chimeric rbcL 5' UTR:GUS transcripts, replacement of single nucleotides in the 10-nt sequence 5'-AUUUCCGGAC-3', extending from positions +38 to +47 relative to the transcripts' 5' terminus, shortened transcript longevity and led to a reduction in transcript abundance of more than 95%. A similar…
Changes in the 5?-untranslated region of the rbcL gene accelerate transcript degradation more than 50-fold in the chloroplast of Chlamydomonas reinha…
2003
Using uidA (beta-glucuronidase; GUS) reporter gene constructs, the 5'-untranslated region (UTR) of the Chlamydomonas chloroplast rbcL gene was screened by deletion and mutational analysis for the presence of a promoter element that previous studies implied to reside within the first 63 base pairs of the UTR. Deleting a large segment of the rbcL 5'UTR in a 3'--5' direction to position +36, changing the remaining 36 base pairs at the 5' end of the UTR, and increasing by five base pairs the distance between the rbcL 5'UTR and the basic promoter element located at position -10 did not abolish transcription from the basic rbcL promoter. It is concluded that the apparent loss of transcriptional a…