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:2.3.1.28 (chloramphenicol acetyltransferase)
5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The type 1 glucose transporter (GLUT1) gene encodes an integral membrane glycoprotein responsible for facilitating transfer of glucose across plasma membrane and is rapidly activated by serum, growth factors, and by oncogenic transformation. To elucidate the molecular mechanisms of regulation of GLUT1 gene expression, we isolated and characterized the mouse GLUT1 gene. DNA elements regulating transcription of the gene were analyzed in transient expression assays after transfection of NIH/3T3 cells with a low background chloramphenicol acetyltransferase (CAT) vector system pSVOOCAT. We identified two enhancer elements; the first one is located 2.7 kilobases upstream of the cap site of the gene which contains the homologous sequences with two 12-O-tetradecanoylphorbol-13-acetate-responsive elements (TREs), a serum response element, a cyclic AMP-responsive element (CRE) and three GC boxes, and the second one is located in the second intron of the gene which contains the homologous sequences with two TREs and one CRE. With the promoter alone the transcription of the gene is activated by src, only slightly activated by ras and is not activated by serum and platelet-derived growth factor. When the gene is accompanied by one of these enhancers, the transcription is activated by all these stimuli.
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PMID:Identification of two enhancer elements in the gene encoding the type 1 glucose transporter from the mouse which are responsive to serum, growth factor, and oncogenes. 133 57

Expression of the platelet-derived growth factor (PDGF) A-chain gene is known to give rise to multiple transcripts of different sizes. Northern blot analysis, using a set of DNA probes corresponding to various parts of the human PDGF A-chain gene, indicated heterogeneity in both the 5' and 3' end of the transcripts. The 3' heterogeneity was shown to be the result of differential use of three polyadenylation signals. S1-nuclease protection- and chloramphenicol acetyltransferase (CAT)-assays, revealed the 5' heterogeneity to be the consequence of two alternative promoters. Whereas the upstream promoter contained typical TATA- and CAAT-boxes, the downstream promoter lacked a TATA-box but seemed to be composed of several GC-boxes.
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PMID:Platelet-derived growth factor (PDGF) A-chain mRNA heterogeneity generated by the use of alternative promoters and alternative polyadenylation sites. 136 Aug 4

The platelet-derived growth factor (PDGF) A- and B-chain genes are widely expressed in mammalian tissues and their homodimeric gene products appear to regulate the autocrine growth of both normal and transformed cells. In this study, we analyzed the 5' flanking sequences of the human PDGF A-chain gene to seek elements important to regulating its transcription. The promoter region was exceptionally G + C-rich and contained a "TATA box" but no "CAAT box." The transcription start site was identified 845 base pairs 5' to the translation initiation site by S1 nuclease mapping and by primer extension. Both in vitro transcription and transient expression of the chloramphenicol acetyltransferase gene linked to the PDGF A-chain 5' flanking sequences established that the putative promoter region was active, and RNase H mapping established that the three characteristic mRNAs (1.9, 2.3, and 2.8 kilobases) used the same transcription start site, which was used in normal endothelial cells and in two human tumor cell lines that express high levels of A-chain transcripts. The results established an exceptionally G + C-rich promoter region and a single transcription start site active for each of the three mRNAs of the PDGF A-chain gene. DNA sites of potential importance in mediating the activation of the PDGF A-chain gene in normal cells and in transformed cell lines expressing high levels of PDGF A chain were identified.
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PMID:Promoter region of the human platelet-derived growth factor A-chain gene. 184 7

Platelet-derived growth factors (PDGFs) are growth-regulatory molecules that stimulate chemotaxis, proliferation, and increased metabolism of primarily connective tissue cells. In a survey of normal tissues, we found specific immunostaining for PDGF B-chain in neurons, principal dendrites, some axons, and probable terminals throughout the brain, in the dorsal horn of the spinal cord, and in the posterior pituitary of a nonhuman primate (Macaca nemestrina). PDGF activity was extracted from brain cortex and posterior pituitary, and ubiquitous expression of transcripts for the two chains of PDGF and both PDGF receptors was detected throughout the brain and posterior pituitary. A transgenic model was also evaluated in which the chloramphenicol acetyltransferase gene was placed under transcriptional control of the PDGF B-chain promoter. The transgene was preferentially expressed within neural cell bodies in the cortex, hippocampus, and cerebellum. PDGF may act as a neuronal regulatory agent. Neuronal release of PDGF could contribute to nerve regeneration and to glial proliferation that leads to gliosis and scarring.
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PMID:PDGF B-chain in neurons of the central nervous system, posterior pituitary, and in a transgenic model. 198 68

We used a dominant inhibitory mutation of c-Ha-ras which changes Ser-17 to Asn-17 in the gene product p21 [p21(Asn-17)Ha-ras] to investigate ras function in mitogenic signal transduction. An NIH 3T3 cell line [NIH(M17)] was isolated that displayed inducible expression of the mutant Ha-ras gene (Ha-ras Asn-17) via the mouse mammary tumor virus long terminal repeat and was growth inhibited by dexamethasone. The effect of dexamethasone induction on response of quiescent NIH(M17) cells to mitogens was then analyzed. Stimulation of DNA synthesis by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) was completely blocked by p21(Asn-17) expression, and stimulation by serum, fibroblast growth factor, and platelet-derived growth factor was partially inhibited. However, the induction of fos, jun, and myc by EGF and TPA was not significantly inhibited in this cell line. An effect of p21(Asn-17) on fos induction was, however, demonstrated in transient expression assays in which quiescent NIH 3T3 cells were cotransfected with a fos-cat receptor plasmid plus a Ha-ras Asn-17 expression vector. In this assay, p21(Asn-17) inhibited chloramphenicol acetyltransferase expression induced by EGF and other growth factors. In contrast to its effect on DNA synthesis, however, Ha-ras Asn-17 expression did not inhibit fos-cat expression induced by TPA. Conversely, downregulation of protein kinase C did not inhibit fos-cat induction by activated ras or other oncogenes. These results suggest that ras proteins are involved in at least two parallel mitogenic signal transduction pathways, one of which is independent of protein kinase C. Although either pathway alone appears to be sufficient to induce fos, both appear to be necessary to induce the full mitogenic response.
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PMID:Effect of a dominant inhibitory Ha-ras mutation on mitogenic signal transduction in NIH 3T3 cells. 211 93

The zif268 gene, which encodes a protein with three typical zinc finger sequences, is induced in mouse 3T3 cells by serum, phorbol 12-myristate 13-acetate platelet-derived growth factor, and fibroblast growth factor. The induction is coordinate with that of c-fos. The 5'-flanking region of zif268 contains sequences that resemble known regulatory elements, including four CC(A or T)6GG sequences similar to the core serum response elements (SREs) found upstream of c-fos and actin genes. To determine whether the zif268 SRE-like elements mediate induction, CAT (chloramphenicol acetyltransferase) plasmids with different lengths of zif268 upstream sequences were tested for inducibility in 3T3 cells by serum, platelet-derived growth factor, or phorbol 12-myristate 13-acetate. In addition, double-stranded oligonucleotides corresponding to each of the four zif268 putative SREs were tested individually for responsiveness when placed upstream of a thymidine kinase gene promoter. Each of the four SREs conferred inducibility by the agents tested, and multiple SREs resulted in greater inducibility than did a single element. Each of the zif268 SREs also competed with the c-fos SRE for binding by serum response factor present in HeLa cell nuclear extract. We conclude that the zif268 SRE-like sequences are functional and probably account for the coordinate induction of zif268 and c-fos.
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PMID:Functional serum response elements upstream of the growth factor-inducible gene zif268. 251 79

Thrombospondin (TSP) is an extracellular matrix glycoprotein whose synthesis and secretion by mesenchymal cells is regulated at the level of gene transcription by platelet-derived growth factor. To examine the transcriptional regulation of the TSP gene at the molecular level, a genomic clone containing the human TSP promoter and flanking sequence was isolated and characterized. A 3.8-kilobase pair (kb) DNA fragment containing the first three exons, the first two introns, and 2.2 kb of 5'-flanking region was sequenced, and the site of transcription initiation was determined by both primer extension and S1 nuclease mapping. Consensus sequences for several potential regulatory elements were found in the 5'-flanking sequence, including a TATA box consensus sequence, TTTAAAA, located 24 base pairs upstream from the transcription start site. A chimeric gene was constructed containing the first intron, the first exon, and 2.0 kb of 5'-flanking sequence of the TSP gene fused to the promoterless gene for chloramphenicol acetyltransferase. When transfected into COS-1 or NIH3T3 cells this gene construct was transcribed, indicating the presence of a functional promoter in the TSP sequence. Transient transfection studies using deletion mutants of this TSP-chloramphenicol acetyltransferase construct were performed to locate cis-acting regulatory sequences. The deletion of flanking sequence 5' to position -234 had little or no effect on transcriptional activity, whereas deletion of 5'-flanking sequence extending further in the 3' direction resulted in the gradual loss of transcriptional activity. The removal of the first intron resulted in a 4-fold decrease in transcript levels, indicating the presence of a cis-acting positive element(s) in the first intron of the human TSP gene. This element(s) was further localized to the region between position +576 and position +727.
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PMID:Characterization of the promoter region of the human thrombospondin gene. DNA sequences within the first intron increase transcription. 254 87

We have previously shown that the SIS/platelet-derived growth factor B chain contains a nuclear targeting signal near its C terminus. Here we show that the platelet-derived growth factor A chain also contains a nuclear targeting signal encoded by an exon which is subject to alternative splicing. This sequence is capable of targeting a nonsecreted form of the A chain to the nucleus and can also target the cytoplasmic proteins dihydrofolate reductase, chloramphenicol acetyltransferase, and pyruvate kinase to the nucleus.
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PMID:The alternatively spliced exon of the platelet-derived growth factor A chain encodes a nuclear targeting signal. 274 50

Comparative analysis of cosmid clones containing the human and feline c-sis genetic regions revealed the similar structural organization of these areas in the two species. The areas shared seven different genetic regions in and around the c-sis locus and of these was related to v-sis. Another region, 1.9 kbp in size and located about 8 kbp upstream of the v-sis homologous region in the human genome, also hybridized to the main c-sis transcriptional product of 3.5 kb. Comparison with a recently described c-sis cDNA clone (Collins et al., Nature 316, 748-750 (1985)) revealed that the 1.9 kbp DNA region contained a large 5' c-sis exon of at least 1050 bp. In this exon, the presumed initiation site of the predicted PDGF-2 containing precursor protein was located and appeared to be preceded by a large untranslated region. In the region immediately upstream of this exon, a TATA box and a consensus sequence for a potential Sp1 binding site were found at similar positions in both species. This region also exhibited promoter activity when tested in an assay in which coding sequences of bacterial chloramphenicol acetyltransferase (CAT; acetyl-CoA: chloramphenicol 3-O-acetyltransferase, EC 2.3.1.28) were placed under its control. The five other DNA regions were found upstream and downstream of the human c-sis transcription unit and also in an intron. Four of them contained repetitive sequences. Hybridization analysis of human and feline c-sis containing cosmid clones with a mixed synthetic nucleotide probe, which corresponded to sequences encoding amino acid residues 2-7 of chain 1 of platelet-derived growth factor (PDGF-1), suggested that the c-sis cosmid clones did not include PDGF-1-specific genetic sequences.
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PMID:Structure and nucleotide sequence of the 5' region of the human and feline c-sis proto-oncogenes. 300 95

The hallmark of "beta 2-interferon (IFN-beta 2)/hepatocyte-stimulating factor/interleukin 6" gene expression is its inducibility in different types of human cells (fibroblasts, monocytes, epithelial cells, and endothelial cells) by different stimuli, which include cytokines such as tumor necrosis factor, interleukin 1 (IL-1) and platelet-derived growth factor, different viruses, and bacterial products such as endotoxin. The activation by cytokines, viruses, and second messenger agonists of the IFN-beta 2 promoter linked to the bacterial chloramphenicol acetyltransferase (CAT) gene was studied after transfection into HeLa cells. A chimeric gene containing IFN-beta 2 DNA from -1180 to +13 linked to the CAT gene was inducible approximately 10-fold by phorbol 12-myristate 13-acetate (PMA), followed, in decreasing order, by pseudorabies and Sendai viruses (7- to 11-fold each); serum (6- to 9-fold); the cytokines tumor necrosis factor, IL-1, and epidermal growth factor (3- to 5-fold each); the cAMP agonists BrcAMP and forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (2- to 6-fold each); poly(I).poly(C) (2- to 4-fold); 1,2-diacylglycerol and the calcium ionophore A23187 (1.5- to 2-fold each). Bacterial endotoxin did not activate this IFN-beta 2/CAT fusion gene in HeLa cells. Deletion of the 5' boundary of the IFN-beta 2 DNA from -1180 to -596 in the fusion gene preserved its activation by IL-1, tumor necrosis factor, epidermal growth factor, serum, pseudorabies, and Sendai viruses and by PMA, Br-cAMP, and forskolin; deletion to -225 led to a small reduction (by a factor of 1.5-2) in the responsiveness to serum, PMA, and Sendai virus but not to the other inducers; a further deletion to -112 greatly reduced all responsiveness. Thus, the region between -225 and -113 in IFN-beta 2, which contains DNA motifs similar to the regulatory elements in the human c-fos gene, appears to contain the major cis-acting regulatory elements responsible for the activation of the IFN-beta 2 promoter by several different cytokines, viruses, and second messenger agonists.
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PMID:Activation of the human "beta 2-interferon/hepatocyte-stimulating factor/interleukin 6" promoter by cytokines, viruses, and second messenger agonists. 304 22


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