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 5' flanking region of the mouse renin genes (Ren-1d and Ren-2d) contains two motifs that are homologous to known negative regulatory elements (NREs). Ren-2d has a 150-base-pair (bp) insertion 5' to the upstream putative NRE (NRE-1), which is lacking in Ren-1d. We tested the functionality of these sequences by using site-directed mutagenesis to delete individually each putative NRE from Ren-1d and to delete the 150-bp insertion from Ren-2d. We examined the effect of these mutations on the expression of the reporter gene chloramphenicol acetyltransferase, which was expressed from a truncated thymidine kinase promoter fused to the renin regulatory region. This plasmid was transfected into human choriocarcinoma JEG-3 cells. Only the upstream NRE (positions -619 to -597) was found to be functional in Ren-1d. The deletion of a 150-bp insertion from Ren-2d resulted in the suppression of chloramphenicol acetyltransferase activity to the level of Ren-1d expression. These data suggest that the upstream NRE that is functional in Ren-1d, but not in Ren-2d, may be partly responsible for differential expression of the renin genes in various tissues. The molecular mechanism of the NRE was examined by studying its interaction with nuclear proteins in submandibular gland and JEG-3 cells by gel-mobility-shift assays. Specific nuclear protein binding was observed only to the upstream NRE and the molecular mass of this protein was approximately 72 kDa as determined by Southwestern blot analysis. Thus our results suggest that both Ren-1d and Ren-2d conserve a cis-acting NRE in the 5' flanking region. In Ren-1d, this NRE could bind a specific nuclear protein resulting in the inhibition of Ren-1d expression in these tissues. On the other hand, the NRE in Ren-2d is nonfunctional due to interference by an adjacent 150-bp insertion.
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PMID:Identification of a negative regulatory element involved in tissue-specific expression of mouse renin genes. 173 3

We have previously produced transgenic mice carrying the human renin gene, whose expression is regulated in a tissue-specific manner. In the present study, we further characterized expression of the transgene. Northern blot analysis showed that the human renin gene is expressed in the kidney but not in the liver of two lines of transgenic mice with 10 and 50 copies of the transgene, suggesting that the integrated copy number of the human renin gene does not influence the dominant-renal expression pattern. Immunohistochemical study using a monoclonal antibody specific for human renin demonstrated that expression of human renin in the transgenic mouse kidney is confined to the epithelioid juxtaglomerular cells. Transfection experiments indicated that the chloramphenicol acetyltransferase fusion gene containing the 3-kb upstream sequences of the renin gene is activated only in human epithelioid embryonic 293 cells derived from kidney but not in human HepG2 cells from liver. These findings suggest that transfer of the cloned renin gene into mice and in vitro cultured cell lines can give rise to cell type-specific expression.
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PMID:Cell type-specific expression of the human renin gene. 176 56

We have constructed pUCSV0cat with low background of chloramphenicol acetyltransferase (CAT) activity and pUCSV3cat (positive control), both containing a SV40 polyadenylation signal 5' to the CAT-coding gene and to the SV40 promoter, respectively. Using this modified pUCSV0cat, we found that human embryonic 293 cells have the ability to activate the promoter of the human renin gene. In addition, we identified the cis-acting sequences responsible for cell-specific expression of the human angiotensinogen gene in its 5'-flanking region.
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PMID:Regulation of human renin and angiotensinogen genes. 180 39

The human renin gene is expressed in the kidney, placenta, and several other sites. The release of renin or its precursor, prorenin, can be affected by several regulatory agents. In this study, primary cultures of human placental cells were used to examine the regulation of prorenin release and renin mRNA levels and of the transfected human renin promotor linked to chloramphenicol acetyltransferase reporter sequences. Treatment of the cultures with a calcium ionophore alone, calcium ionophore plus forskolin (that activates adenylate cyclase), or forskolin plus a phorbol ester increased prorenin release and renin mRNA levels 1.3- to 6-fold, but several classes of steroids did not affect prorenin secretion or renin RNA levels. The transfected renin promoter (584 or 100 base pairs of 5'-flanking DNA) initiated at the correct start site in these cells and forskolin increased its expression 2.5- to 4-fold. Constructs containing renin 5'-flanking DNA linked to a heterologous promoter cotransfected into HeLa cells with either glucocorticoid or estrogen receptor expression vectors were not regulated by dexamethasone or 17 beta-estradiol. These results suggest that (i) the first 584 base pairs of the renin gene 5'-flanking DNA do not contain functional glucocorticoid or estrogen response elements, (ii) placental prorenin release and renin mRNA are regulated by calcium ion and by the combinations of cAMP with either C kinase or calcium ion, and (iii) the first 100 base pairs of the human renin 5'-flanking DNA direct accurate initiation of transcription and can be regulated by cAMP. Thus, some control of renin release in the placenta (and by inference in other tissues) occurs via transcriptional influences on its promoter.
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PMID:Regulation of human renin expression in chorion cell primary cultures. 221 88

The 5' flanking regions of the mouse renin genes (Ren1d and Ren2d) contain putative negative control and cAMP responsive elements. Sequence analysis shows additionally that these putative control elements in the Ren2d gene are interrupted by a 160-base-pair insertion. To document the functions of these elements, we isolated these regions and fused them to the reporter gene chloramphenicol acetyltransferase (CAT), which was linked upstream to a thymidine kinase (TK) promoter (pUTKAT1). The chimeric constructs were transfected into mouse pituitary tumor AtT-20 and human choriocarcinoma JEG-3 cells. At the basal unstimulated condition, Ren1d 5' flanking sequence in the sense orientation inhibited basal CAT expression from the TK promoter of pUTKAT1, whereas the same sequence in the antisense orientation did not. The 5' flanking region of Ren2d had no inhibitory effect on basal CAT expression. These data demonstrate that the negative control element is functional in Ren1d but is nonfunctional in Ren2d, suggesting that the 160-base-pair insertion in Ren2d interferes with the function of the negative control elements. In response to 8-bromo-cAMP, both renin genes increased transcription 3-fold, suggesting a functional cis action of the cAMP responsive element in both genes. These data may be important in the understanding of the regulation of the tissue-specific expression of mouse renin genes.
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PMID:Negative control elements and cAMP responsive sequences in the tissue-specific expression of mouse renin genes. 253 60

Renin gene expression is tissue-specific and under complex hormonal control. To investigate which DNA elements are involved in the control of human renin gene expression, we performed transient DNA transfer experiments with renin-chloramphenicol acetyltransferase fusions. We have mapped a complex arrangement of positive and negative control sequences in the 5' flanking region of the human renin gene. One positive control element is active in either orientation and defines a renin gene enhancer. The negative element is also active in either orientation and defines a renin gene silencer. Mapping in the same region as the silencer is a cAMP-responsive element, a sequence conserved in mouse, rat, and human renin genes.
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PMID:Identification of negative and positive regulatory elements in the human renin gene. 254 Jan 88

Expression of the human renin gene is regulated in a tissue-specific manner, but study of this regulation has been limited by a lack of suitable cell lines that simulate endogenous control. In order to characterize the regulation of renin gene expression, the 5' flanking region (892 base pairs) from the human renin gene was linked to the chloramphenicol acetyltransferase gene and was introduced into multiple human cell lines by calcium phosphate precipitation or electroporation methods to assess transcriptional control. The human renin promoter was active when transfected into cultured human choriocarcinoma cells (JEG-3) and rat vascular smooth muscle cells, but it was not active in many other cloned cell types. These results suggest that selective cell lines contain the specific trans-acting factors necessary for human renin gene expression, and support the concept of cell-specific expression of this gene.
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PMID:Functional human renin promoter in transfected cells: evidence for cell-specific expression. 307 83

DBA/2J mouse contains two renin gene loci (Ren1d and Ren2d). Ren2d but not Ren1d is expressed in submandibular gland (SMG) while both are expressed in the kidney. Based on vitro studies, we have postulated that a negative regulatory element (NRE) in the renin gene promoter is involved in its tissue-specific expression. In this study, we examined the molecular mechanism at the in vivo level using direct gene transfer. Fragments of the Ren1d or Ren2d promoter were fused to a chloramphenicol acetyltransferase (CAT) gene expression vector. These constructs complexed in fusogenic liposomes were injected directly into the mouse SMG or intraarterially into the mouse kidney via the renal artery. The vector containing the CAT exhibited readily detectable in vivo expressions in both SMG and kidney. In the SMG, Ren1d fragment containing the NRE abolished CAT expression while deletion of the NRE restored CAT expression. The homologous fragment from the Ren2d promoter did not inhibit CAT expression while deletion of the 150-bp insertion resulted in the inhibition. Cotransfection of Ren1d construct with Ren1d-NRE oligonucleotides as transcriptional factor decoy restored CAT expression. Contrary to the SMG, transfection with Ren1d fragment-CAT construct or Ren2d fragment-CAT construct into the kidney resulted in similar levels of CAT expression. Interestingly, human c-myc NRE oligonucleotides which share homology with Ren1d-NRE competed effectively with these oligonucleotides for the regulation of Ren1d gene expression in vivo. This NRE sequence is also homologous to silencer elements found in multiple mammalian genes, suggesting the presence of a family of NRE/NRE binding proteins regulating expression of diverse genes.
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PMID:In vivo identification of a negative regulatory element in the mouse renin gene using direct gene transfer. 765 96

Renin is produced mainly by the kidney, and cAMP is a main positive regulator of its synthesis. This study was undertaken to analyze the molecular mechanism of cAMP-mediated regulation of Ren-1C gene transcription by the proximal promoter. We first showed that the promoter region from -365 to +16 of the mouse renin gene (Ren-1C) mediated the cAMP-induced chloramphenicol acetyltransferase gene expression in embryonic kidney-derived 293 cells. Deletion analysis and heterologous promoter assay disclosed that the proximal promoter region from -75 to +16 was able to activate chloramphenicol acetyltransferase expression by cAMP, and indicated that the proximal promoter element from -75 to -47 (RP-2 element) overlapping the TATA-like region was able to confer cAMP responsiveness. Electrophoretic mobility shift assay and DNase I footprinting analysis demonstrated that novel nuclear factors in 293 cells interacted with the RP-2 element, and that cAMP increased the binding activity of these nuclear factors to the RP-2 element. Furthermore, we demonstrated that cAMP enhanced the binding of nuclear factors derived from juxtaglomerular cells, the main production site of renin in the kidney, to the RP-2 element in vivo. These results suggest that the RP-2 element plays an important role in the cAMP-mediated regulation of Ren-1C gene transcription through the proximal promoter.
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PMID:Mechanism of cAMP regulation of renin gene transcription by proximal promoter. 796 42

In order to identify the mechanism by which cyclic AMP stimulates expression of the human renin gene (REN), the effect of forskolin was tested in transient expression analyses of REN 5'-flanking DNA-chloramphenicol acetyltransferase (CAT) reporter gene constructs in secondary cultures of human chorio-decidual cells, a major site of renin synthesis. Forskolin induced a mean 5-fold stimulation which was localized to DNA in the region -249 to -162 with respect to the transcription start site (+1). Such DNA also mediated a response to forskolin in heterologous (HSV thymidine kinase) promoter constructs. Strong cAMP-response element (CRE) homology at -222 to -218 resembled the target for members of the CRE binding protein (CREB) family. Gel shift assays demonstrated similarly migrating nucleoprotein complexes for oligonucleotides containing the putative REN CRE as for a canonical CRE, in chorio-decidual, JEG-3 and HeLa nuclear extracts. Mutation of residues critical for CREB attachment reduced binding. In conclusion, a CRE was identified at -222 to -218 that appears critical for cAMP-induced human renin gene transcription.
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PMID:Identification of cyclic AMP response element in the human renin gene. 816


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