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 transcriptionally active RVL3-VL30 element contains a triple repeat of TGACTCC, a sequence nearly identical to the AP-1 binding site. However, 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation was unable to elicit chloramphenicol acetyltransferase (CAT) expression from a construct containing these AP-1-like sequences upstream of the thymidine kinase promoter present in pTES. Endothelin, which activates protein kinase C (pkC) and elevates intracellular Ca2+ in Rat-1 cells, was effective in stimulating CAT expression from the VL30-pTES construct. We attempted to assess the relative importance of these second messenger systems by stimulating each pathway separately with exogenous agonists. We determined that neither stimulation of pkC by the tumor promoter TPA nor elevation of intracellular Ca2+ by the tumor promoter thapsigargin was sufficient to stimulate CAT expression from the VL30-pTES vector. When combined, the two tumor promoters induced a synergistic increase in CAT expression. Our data indicate that elevation of intracellular Ca2+ by thapsigargin was not required for full activation of pkC by TPA. First, TPA was able to stimulate expression of other genes in Rat-1 cells, indicating full activation of pkC. Second, thapsigargin synergized effectively with epidermal growth factor to stimulate CAT activity from the VL30-pTES construct in cells depleted of pkC activity by chronic TPA treatment. The permissive effects of thapsigargin on gene expression were also observed for an endogenous gene, transin/stromelysin. The permissive effects of elevated intracellular Ca2+ levels may represent a general mechanism for the stimulation of some genes by pkC-mediated pathways.
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PMID:Two tumor promoters, 12-O-tetradecanoylphorbol-13-acetate and thapsigargin, act synergistically via distinct signaling pathways to stimulate gene expression. 212 50

Stromelysin is a member of the metalloproteinase family which plays an important role in extracellular matrix remodelling during many normal and disease processes. We show here that in polyomavirus-transformed rat embryo fibroblast cells (PyT21), the transcription from the stromelysin gene is repressed by the vitamin A derivative retinoic acid (RA). Furthermore, expression vectors encoding the human RA receptors hRAR-alpha, hRAR-beta and hRAR-gamma repress chloramphenicol acetyltransferase (CAT) expression from stromelysin promoter-CAT gene expression vectors in RA-treated PyT21 and human HeLa cells, as determined by transient transfection assays. Through mutation and deletion analysis, we show that the RA dependent repression is mediated by a 25 bp region from nucleotide positions -72 to -48 of the rat stromelysin 5'-flanking DNA sequence. Further mutation analysis of this region indicates that the DNA sequence required for RA dependent repression colocalizes with an AP1 binding site which is essential for promoter activity. We show also that RA represses the transcriptional activity of a reporter gene containing a TPA responding AP1 binding site driving the HSV tk promoter. Thus the RAR-RA complex appears to repress transcription of the stromelysin gene by blocking activation by positive regulatory factors. However, we found no evidence supporting the possibility that the RA dependent repression could be due to RAR binding to the AP1 binding site or to the AP1 components c-fos and c-jun.
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PMID:Negative regulation of the rat stromelysin gene promoter by retinoic acid is mediated by an AP1 binding site. 217 52

Stromelysin is a member of a gene family of metalloproteinases involved in extracellular matrix remodeling in normal and diseased processes. Primary cultures of rheumatoid synovial cells produce large amounts of metalloproteinase mRNA and proteins. We cloned a cDNA for human stromelysin from a rheumatoid synovial cell cDNA library, and we used the cDNA to isolate the gene for human stromelysin and a related gene, stromelysin 2. We sequenced parts of the genes and found that both are contained on approximately 14 kilobase pairs of DNA. Using an exon-containing fragment of the stromelysin 2 genomic clone as a specific probe in Northern blot analysis, we demonstrate the differential expression of stromelysin and stromelysin 2 in rheumatoid synovial cells, human foreskin fibroblasts, and rabbit synovial fibroblasts. In addition, using chimeric constructs of the stromelysin promoter linked to the bacterial gene chloramphenicol acetyltransferase (CAT), we show that the elements required for the tumor promoter phorbol myristate acetate (PMA), epidermal growth factor (EGF), and interleukin 1 beta (IL-1 beta) induction are contained on a 307 base pair fragment which includes approximately 270 base pairs (bp) of 5'-flanking DNA. The cloning of the human stromelysin and stromelysin 2 genes, the documentation of their differential expression, and the identification of transcriptional regulatory regions in the stromelysin gene will facilitate the study of metalloproteinase gene expression in normal processes and in diseases such as rheumatoid arthritis.
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PMID:Cloning of the genes for human stromelysin and stromelysin 2: differential expression in rheumatoid synovial fibroblasts. 260 16

The stromelysin gene encodes a potent tissue-degrading proteinase whose activity is important in tissue-remoldeling processes such as wound healing, the inflammatory reaction, rheumatoid arthritis, tumor invasion, and possibly embryonic development. In light of the ability of interleukin-1 to amplify, and ability of glucocorticoids to attenuate the inflammatory response, we tested interleukin-1 and dexamethasone for regulatory effects on stromelysin gene expression. We report that interleukin-1 induces the stromelysin gene, and dexamethasone diminishes the level of induction by interleukin-1, epidermal growth factor, phorbol ester, and cAMP elevation (elicited by cholera toxin). Similar responses are conferred upon a chloramphenicol acetyltransferase coding sequence by a 700-base pair stromelysin 5'-flanking fragment, implying transcription regulation by sequence elements in this region.
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PMID:Transcription from the stromelysin promoter is induced by interleukin-1 and repressed by dexamethasone. 282 88

The AP-1 consensus sequences (TGAGTCA) are the major 12-O-tetradecanoylphorbol113-acetate (TPA) responsive elements shared by several TPA inducible genes, such as c-sis, c-fos, c-myc, collagenase, stromelysin, hMTIIA and SV40. However, the role of AP-1 binding sites, which are present in the introns 3, 5, and 11 of ODC gene, in the regulation of TPA-induced ornithine decarboxylase (ODC) gene transcription are unknown. We determined the TPA responsiveness of the AP-1 sequences in the introns of ODC gene in CV-1 cells which induce ODC activity and mRNA in response to TPA treatment. ODC introns containing AP-1 sequences were inserted into the chloramphenicol acetyltransferase (CAT) reporter gene. Transient transfection of CV-1 cells with the intron-CAT constructs followed by TPA treatment did not induce CAT activity. However, when flanking regions of the AP-1 site in intron 3 were narrowed down to 74 bp, TPA induced CAT activity by 5- to 7-fold. The TPA-inducibility could be eliminated by mutation of the AP-1 site (TGAGTCA-->TGATGCCA or TGATGA) in 74 bp of intron 3. These results indicate that the AP-1 sequences in the intact ODC introns may not be responsive to TPA. The flanking sequences of the AP-1 site may be crucial to determine whether the AP-1 site is accessible to the TPA-induced transcriptional factor(s).
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PMID:Lack of 12-O-tetradecanoylphorbol-13-acetate responsiveness of ornithine decarboxylase introns which have AP-1 consensus sequences. 765 80

An Ets-related E1A-F has been characterized as an enhancer-binding protein for the adenovirus E1A gene. Here we show, in transient expression assays, that E1A-F can activate three different subclasses of the matrix metalloproteinase gene promoters. Expressions of the chloramphenicol acetyltransferase (CAT) reporter gene under the control of stromelysin, type I collagenase and 92 kD type IV collagenase promoters were increased approximately 10- to 20-fold by co-transfection with the E1A-F expression vector. Activation levels were as much high as those obtained by exogenous expression of AP-1 transcription factor. These results suggest that E1A-F positively regulates transcriptions from matrix metalloproteinase genes that are associated with invasion and metastasis of tumor cells.
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PMID:Ets-related protein E1A-F can activate three different matrix metalloproteinase gene promoters. 773

Stromelysins, which are the metalloproteinases with the widest substrate specificities, play a critical role in tumor invasion and metastasis. We have previously reported an element (SPRE) of the stromelysin promoter located between nucleotides -1221 and -1203 that is necessary and sufficient for the control of stromelysin gene expression by mitogenic activation, which induces a nuclear activity that binds to this sequence. Using a concatenated probe with several copies of this element to screen a lambda gt11 cDNA expression library from mouse Swiss 3T3 fibroblasts, we report here the molecular cloning of a cDNA coding for a novel protein (SPBP) of 937 amino acids that binds to this element and has several features of a transcription factor, such as a putative leucine zipper region, a nuclear localization signal, and a basic domain with homology to the DNA-binding domains of Fos and Jun. Evidence that SPBP is at least a critical component of the mitogen-induced SPRE nuclear binding activity is presented here. Furthermore, the transfection of an expression plasmid for SPBP transactivates reporter chloramphenicol acetyltransferase plasmids containing either the full-length stromelysin promoter or a single copy of the SPRE cloned upstream of the herpes simplex virus thymidine kinase minimal promoter. Therefore, the results presented here identify a novel transcription factor critically involved in the control of stromelysin expression.
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PMID:Molecular characterization of a novel transcription factor that controls stromelysin expression. 776 Aug 12

Transforming growth factor beta (TGF-beta) is a potent modulator of cell growth in many systems. In normal rat kidney fibroblasts, TGF-beta 1 increases epidermal growth factor (EGF) receptor gene transcription and synergizes with EGF to stimulate growth in soft agar, a characteristic of the transformed phenotype. In order to identify the target of TGF-beta 1 action, we have used a series of 5' deletion mutants of the EGF receptor promoter linked to a chloramphenicol acetyltransferase reporter gene (ERCAT). The TGF-beta response element(s) was localized to a cis-regulatory region which resides between positions -919 and -860 relative to the ATG translation initiation codon of the EGF receptor promoter. This 60-base pair region contains a repressor of the EGF receptor promoter and a TGF-beta inhibitory element that mediates TGF-beta 1 suppression of transin/stromelysin gene transcription through binding of a Fos-containing protein complex. Cotransfection of c-fos, c-jun, or both expression vectors with the intact or 5'-deleted ERCAT constructs identified several Fos-responsive inhibitory regions within the EGF receptor promoter, but these did not localize to the -919 to -860 promoter region. Mobility shift assays showed binding of the 60-base pair DNA fragment to proteins in extracts from untreated normal rat kidney cells; the binding was specifically competed by oligonucleotides containing a CAGATG sequence but not by oligonucleotides containing the EGF receptor repressor or the TGF-beta inhibitory element. TGF-beta 1 treatment but not anti-Fos antibody caused a decrease in specific 60-base pair DNA-protein complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of epidermal growth factor receptor gene transcription by transforming growth factor beta 1: association with loss of protein binding to a negative regulatory element. 798 46

Matrix metalloproteinases are secreted enzymes important in inflammation and tumor invasion. Earlier, we demonstrated that in normal human FS-4 fibroblasts, collagenase and stromelysin mRNA levels are increased not only after treatment with known matrix metalloproteinase inducers such as tumor necrosis factor (TNF), interleukin-1, and 12-O-tetradecanoylphorbol-13-acetate, but also with interferon-beta (IFN-beta). In this study, we compared the regulation of these matrix metalloproteinase genes by TNF and IFN-beta. We show that both TNF and IFN-beta increase steady-state levels of collagenase and stromelysin mRNAs with similar slow kinetics. The glucocorticoid dexamethasone blocked matrix metalloproteinase induction by both cytokines. The protein synthesis inhibitor cycloheximide inhibited collagenase mRNA induction by TNF or IFN-beta, suggesting that induction by both agents is indirect. Consistent with these observations, both TNF and IFN-beta increased c-fos and c-jun mRNA levels. Furthermore, treatment with TNF or IFN-beta increased the transcriptional activity of activator protein-1-responsive chloramphenicol acetyltransferase reporter gene constructs, including a native collagenase promoter-driven chloramphenicol acetyltransferase construct. These findings show that regulation of matrix metalloproteinase gene expression by both TNF and IFN-beta involves the transcription factor activator protein-1 and demonstrate a novel indirect mechanism of type I IFN-induced gene expression.
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PMID:Interferon-beta induces metalloproteinase mRNA expression in human fibroblasts. Role of activator protein-1. 806 4

We have stably expressed a trans-activation suppressing deletion mutant of the human c-jun gene (TAM-67) in the malignant mouse epidermal cell lines 10Gy5 and PDV. Expression of the p26 mJUN protein blocked both constitutive and inducible transcriptional trans-activation of several AP-1 responsive reporter chloramphenicol acetyltransferase constructs. p26 mJUN was able to block both 12-O-tetradecanoylphorbol-13-acetate (TPA) and okadaic acid induced expression of the mouse stromelysin gene in 10Gy5 cells and TPA induced expression of the urokinase-type plasminogen activator gene in PDV cells as determined by Northern analyses. Both genes contain TPA response elements in their promoter regions and are known to be AP-1 responsive. The presence of p26 mJUN in nuclear extracts, as determined by Western blotting, did not detectably alter the DNA binding activity of endogenous AP-1 as determined by gel shift analysis with an oligonucleotide containing a single high affinity AP-1 binding site. UV cross-linking studies coupled with Western analyses identified DNA bound cJUN but not mJUN in nuclear extracts of stably transfected cell lines, suggesting that the mutant JUN protein may exert some of its antioncogenic effects in malignant mouse epidermal cells by a mechanism(s) not involving DNA binding. Malignant mouse epidermal cells which stably expressed the mutant JUN protein were not only inhibited in their AP-1 trans-activation response, but also in their ability to form s.c. tumors in nude mice. These results indicate that inhibition of AP-1 mediated transcriptional trans-activation alone can be sufficient to suppress the tumorigenic phenotype in a subset of malignant mouse epidermal cells.
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PMID:Stable expression of a c-JUN deletion mutant in two malignant mouse epidermal cell lines blocks tumor formation in nude mice. 812 97


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