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)

Tracheobronchial epithelial (TBE) cells that normally do not express the squamous cell differentiation marker gene, SPR1, can be induced to produce it by 12-O-tetradecanoylphorbol-13-acetate (TPA). The regulation of SPR1 gene expression by TPA occurs, in part, at the transcriptional level in primary human and monkey TBE cells. Using a transient transfection assay, we observed that TPA stimulates the activity of the reporter gene, chloramphenicol acetyltransferase, by 2-4-fold in transfected TBE cells. However, this chloramphenicol acetyltransferase activity is cell type-specific with significantly less activity in transformed epithelial cell lines and no activity in non-epithelial cell types. TPA-dependent stimulation can also be demonstrated by co-transfection with plasmid DNAs that overexpress the JUN family of proteins, especially c-JUN. Overexpression of c-JUN and TPA treatment synergistically stimulate the SPR1 promoter activity by more than 40-fold. Deletion analysis of the promoter region demonstrates that the DNA fragment of the first 98 base pairs of the 5'-flanking region contains the basal promoter activity, while the region between -162 and -96 contains the cis-enhancer elements for both the basal and TPA/c-JUN-stimulating promoter activities. This observation is supported by in vivo genomic footprinting studies that reveal persistent protections in the following motifs of this region: -141 TRE, -131 GT, -123 ETS-like, and -111 TRE-like motifs and in the enhanced protections in -141 TRE and -111 TRE-like motifs in cells after the TPA treatment. Site-directed mutagenesis in this region demonstrates the involvement of both -141 TRE and -111 TRE-like motifs in TPA/c-JUN-dependent stimulation as well as enhanced basal transcriptional activity. However, it is primarily the -111 TRE-like motif that is involved in the mediation of the enhanced basal promoter activity of the human SPR1 gene. These results are further supported by gel mobility shift assays that demonstrate the involvement of c-JUN and these TRE motifs in the formation of the DNA-protein complex.
 ...
PMID:Expression of human squamous cell differentiation marker, SPR1, in tracheobronchial epithelium depends on JUN and TRE motifs. 759 61

A mesenchymal-epithelial cell interaction exists in the testis between the Sertoli cells that form the seminiferous tubule and the mesenchymal-derived peritubular myoid cells that surround the tubule. Analysis of the mesenchymal-epithelial interactions between these cells revealed the local production of a mesenchymal factor, PModS. PModS modulates the differentiated functions of Sertoli cells in vitro, including stimulation of the iron-binding protein transferrin (Tf). Previous results have indicated that PModS-induced Tf gene expression involves the activation of immediate early genes. One of the immediate early genes was identified as c-fos. The importance of c-fos was demonstrated in the current study when a c-fos antisense oligonucleotide was found to inhibit the ability of PModS to induce the expression of a Tf promoter-chloramphenicol acetyltransferase (CAT) construct. The regulation of c-fos by PModS was investigated with various CAT constructs containing segments of the c-fos promoter, such as the serum response element (SRE), sis-inducible element (SIE), cAMP response element (CRE), and phorbol ester/TPA response element (TRE), transfected into cultured Sertoli cells. PModS has no effect on cAMP response element-CAT or TRE-CAT, suggesting that PModS does not act through stimulation of cAMP and protein kinase C pathways. PModS was found to activate the c-fos SRE-CAT construct and the SIE-CAT construct. A construct containing both SIE and SRE was stimulated to the same degree as either element alone. Gel mobility shift assays using nuclear extracts from PModS-stimulated Sertoli cells and a radiolabeled SRE oligonucleotide resulted in retarded mobility of a DNA-protein complex. A gel shift with a SRE oligonucleotide containing an ETS domain resulted in a unique shift only detected in PModS stimulated cells. PModS also promoted a gel shift with the SIE that is adjacent to the SRE on the c-fos promoter. The data imply that PModS can activate the c-fos promoter through the SRE and SIE. PModS caused a labeled activating protein 1 (AP1) oligonucleotide to form a DNA-protein complex, indicating activation of the c-fos gene and binding of the c-fos/jun complex. To study the downstream regulation of Sertoli cell differentiation, Tf gene expression was examined. CAT constructs containing deletion mutants of a 3-kilobase (kb) mouse Tf promoter were used. When transfected into Sertoli cells the 581-base pair Tf minimal promoter had only a slight response to PModS, but was activated by FSH. The 2.6-kb Tf promoter construct responded to PModS.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Role of specific response elements of the c-fos promoter and involvement of intermediate transcription factor(s) in the induction of Sertoli cell differentiation (transferrin promoter activation) by the testicular paracrine factor PModS. 778 31

To understand the molecular mechanisms underlying the regulation of hepatocyte growth factor (HGF) gene expression and to define the DNA sequences essential for its cell-type specific and inducible expression, we have isolated and characterized the 5'-flanking region of the HGF gene. A genomic clone containing 2.8 kilobases of the 5'-flanking region of the HGF gene has been isolated from a mouse liver genomic library. Sequence analysis showed that the promoter region of the mouse HGF gene contains a noncanonical TATA box (ATAAA). Further analysis of the 5'-flanking region revealed a number of putative regulatory elements, such as four interleukin-6 response elements (IL-6 RE), two potential binding sites for NF-IL6, a TGF-beta inhibitory element (TIE), a cAMP response element (CRE), two estrogen response elements (ERE) including one located in the first intron, a potential vitamin D response element (VDRE) which overlaps a chicken ovalbumin upstream promoter (COUP) transcription factor binding element, two liver-specific transcription factor (C/EBP) binding sites, and a B cell- and macrophage-specific transcriptional factor binding site (PU.1/ETS). To determine the location of sites that may be critical for the function of the HGF promoter, we constructed a series of chimeric genes containing variable regions of the 5'-flanking sequence of HGF gene and the coding region for chloramphenicol acetyltransferase (CAT). Transient transfection of chimeric plasmids demonstrated that the mouse HGF gene promoter containing 70 base pairs of the 5'-flanking sequences were active in mouse fibroblast NIH 3T3 cells and in human endometrial carcinoma RL95-2 cells. This basal transcription activity of the HGF promoter was modulated in NIH 3T3 and RL95-2 cells by multiple upstream elements. Three positive elements were identified at positions -2848 to -2674, -1386 to -1231, and -699 to -274, and three negative candidate elements were mapped to positions -1652 to -1386, -964 to -699, and -274 to -70, respectively. By the combination of a series of 5'-end deletion and internal deletion, a cell type-specific negative regulatory element in RL95-2 cells was localized to the nucleotide position -964 to -699. Moreover, the reporter plasmid containing interleukin 6 (IL-6) response element was responsive to IL-6 stimulation in stably transfected NIH 3T3 cells. Our findings revealed a complex pattern of transcriptional regulation of the mouse HGF gene expression.
 ...
PMID:Structural and functional characterization of the mouse hepatocyte growth factor gene promoter. 830 76

One of the primary endocrine hormones that influence the onset of Sertoli cell differentiation at puberty and help maintain differentiation in the adult testis is FSH. FSH can modulate the majority of Sertoli cell differentiated functions, including stimulation of the iron-binding protein transferrin. Previous studies have shown that FSH alters the levels of cAMP and the immediate early gene c-fos. The current study was designed to investigate the transcriptional regulation of Sertoli cell differentiation by examining the actions of FSH on the promoter of the immediate early gene c-fos and the promoter of the downstream differentiated function gene transferrin. The regulation of c-fos by FSH was investigated with various chloramphenicol acetyltransferase (CAT) constructs containing segments of the c-fos promoter, such as the serum response element (SRE), cAMP response element (CRE), and AP1/phorbol ester/TPA response element (TRE), that were transfected into cultured Sertoli cells. Observations indicate that FSH can stimulate all three response elements, as well as a whole c-fos promoter construct. Interestingly, FSH was found to have a more dramatic effect on the SRE-CAT than a cAMP analog, suggesting a difference in the actions of the two agents. Gel mobility shift assays were performed to confirm the reporter gene results. Nuclear extracts of FSH-stimulated Sertoli cells caused a labeled AP1 oligonucleotide to form a DNA/protein complex (i.e., gel shift), indicating activation of the c-fos gene and binding of the c-fos/jun complex. Nuclear extracts from both FSH- and cAMP-stimulated Sertoli cells promoted similar gel shifts with SRE and CRE oligonucleotides. This observation supports the reporter gene data in indicating that FSH can influence both the SRE and CRE. A gel mobility shift assay was also performed with an oligonucleotide containing the 5'-flanking ETS domain of the SRE (ETS-SRE) that allows the formation of a ternary complex. FSH-stimulated Sertoli cell nuclear extracts were found to promote a unique ETS-SRE gel shift not present in cAMP-stimulated cells. The observations imply that FSH actions on the SRE are in part distinct from the actions of cAMP. Transferrin gene expression was examined to study the downstream regulation of Sertoli cell differentiation. CAT constructs containing deletion mutants of a 3-kb mouse transferrin promoter were used. When transfected into Sertoli cells, the 581-bp transferrin minimal promoter, previously shown to contain a CRE, had a significant response to cAMP and FSH. The 1.6-, 2.6-, and 3-kg transferrin promoter constructs also responded to FSH and cAMP to the same extent as, or to a lesser extent than, the 581-bp minimal promoter. Interestingly, the actions of FSH on the 581-bp minimal transferrin promoter were more dramatic than those of cAMP. The importance of FSH-induced c-fos in the regulation of transferrin expression was demonstrated in the current study when a c-fos antisense oligonucleotide was found to partially inhibit (50%) the ability of FSH to induce the expression of a transferrin promoter (CAT) construct. Therefore, FSH appears to act through multiple transcriptional activation pathways. The first involves cAMP and the CRE at both early-event genes (e.g., c-fos) and downstream genes (e.g., transferrin). It is likely that other pathways involve alternate signal transduction events (e.g., calcium mobilization) and promoter response elements (e.g., SRE). These multiple pathways may act in a compensatory manner to assure the ability of FSH to influence Sertoli cell differentiation and/or in a synergistic manner to amplify FSH actions.
 ...
PMID:Transcriptional regulation of sertoli cell differentiation by follicle-stimulating hormone at the level of the c-fos and transferrin promoters. 883 93

Cytomegalovirus (CMV) infection is nonpermissive or persistent in many lymphoid and myeloid cell types but can be activated in differentiated macrophages. We have shown elsewhere that both the major immediate-early gene (MIE) and lytic cycle infectious progeny virus expression can be induced in otherwise nonpermissive monocyte-like U-937 cell cultures infected with either human CMV (HCMV) or simian CMV (SCMV) by treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Two multicopy basal enhancer motifs within the SCMV MIE enhancer, namely, 11 copies of the 16-bp cyclic AMP response element (CRE) and 3 copies of novel 17-bp serum response factor (SRF) binding sites referred to as the SNE (SRF/NFkappaB-like element), as well as four classical NFkappaB sites within the HCMV version, contribute to TPA responsiveness in transient assays in monocyte and T-cell types. The SCMV SNE sites contain potential overlapping core recognition binding motifs for SRF, Rel/NFkappaB, ETS, and YY1 class transcription factors but fail to respond to either serum or tumor necrosis factor alpha. Therefore, to evaluate the mechanism of TPA responsiveness of the SNE motifs and of a related 16-bp SEE (SRF/ETS element) motif found in the HCMV and chimpanzee CMV MIE enhancers, we have examined the functional responses and protein binding properties of multimerized wild-type and mutant elements added upstream to the SCMV MIE or simian virus 40 minimal promoter regions in the U-937, K-562, HL-60, THP-1, and Jurkat cell lines. Unlike classical NFkappaB sites, neither the SNE nor the SEE motif responded to phosphatase inhibition by okadaic acid. However, the TPA responsiveness of both CMV elements proved to involve synergistic interactions between the core SRF binding site (CCATATATGG) and the adjacent inverted ETS binding motifs (TTCC), which correlated directly with formation of a bound tripartite complex containing both the cellular SRF and ELK-1 proteins. This protein complex was more abundant in U-937, K-562, and HeLa cell extracts than in Raji, HF, BALB/c 3T3, or HL-60 cells, but the binding activity was altered only twofold after TPA treatment. A 40-fold stimulation of chloramphenicol acetyltransferase activity mediated by four tandem repeats of the SNE could be induced within 2 h (and up to 250-fold within 6 h) after addition of TPA in DNA-transfected U-937 cells, indicating that the stimulation appeared likely to be a true protein kinase C-mediated signal transduction event rather than a differentiation response. Slight differences in the sequence of the core SRF binding site compared with that of the classical c-Fos promoter serum response element, together with differences in the spacing between the SRF and ETS motifs, appear to account for the inability of the SCMV SNEs to respond to serum induction.
 ...
PMID:Synergistic interactions between overlapping binding sites for the serum response factor and ELK-1 proteins mediate both basal enhancement and phorbol ester responsiveness of primate cytomegalovirus major immediate-early promoters in monocyte and T-lymphocyte cell types. 897 Sep 84

Overexpression of human heme oxygenase-1 has been shown to have the potential to promote EC proliferation and angiogenesis. Since Ets-family proteins have been shown to play an important role in angiogenesis, we investigated the presence of ETS binding sites (EBS), GGAA/T, and ETS protein contributing to human HO-1 gene expression. Several chloramphenicol acetyltransferase constructs were examined in order to analyze the effect of ETS family proteins on the transduction of HO-1 in Xenopus oocytes and in microvessel endothelial cells. Heme oxygenase promoter activity was up-regulated by FLI-1ERGETS-1 protein(s). Chloramphenicol acetyltransferase (CAT) assays demonstrated that the promoter region (-1500 to +19) contains positive and negative control elements and that all three members of the ETS protein family were responsible for the up-regulation of HHO-1. Electrophoretic mobility shift assays (EMSA), performed with nuclear extracts from endothelial cells overexpressing HHO-1 gene, and specific HHO-1 oligonucleotides probes containing putative EBS resulted in a specific and marked bandshift. Synergistic binding was observed in EMSA between AP-1 on the one hand, FLI-1, ERG, and ETS-1 protein on the other. Moreover, 5'-deletion analysis demonstrated the existence of a negative control element of HHO-1 expression located between positions -1500 and -120 on the HHO-1 promoter. The presence of regulatory sequences for transcription factors such as ETS-1, FLI-1, or ERG, whose activity is associated with cell proliferation, endothelial cell differentiation, and matrix metalloproteinase transduction, may be an indication of the important role that HO-1 may play in coronary collateral circulation, tumor growth, angiogenesis, and hemoglobin-induced endothelial cell injuries.
 ...
PMID:Upregulation of human heme oxygenase gene expression by Ets-family proteins. 1002 13

Bacterial lipopolysaccharide (LPS) induces a rapid and transient increase in transcription of the tumor necrosis factor-alpha (TNF-alpha) gene in cells of monocyte/macrophage lineage. This study examines the role of potential regulatory elements within the proximal promoter region of the mouse TNF-alpha gene in LPS induction and cyclic AMP (cAMP)-mediated inhibition of TNF-alpha in RAW 264.7 murine macrophage-like cells. Transfection of proximal promoter chloramphenicol acetyltransferase (CAT) reporter constructs demonstrated that this region is LPS inducible in murine RAW 264.7 cells, with a 5.9-fold increase over nonstimulated transfectants. Site-specific mutations of the ETS, activated protein-1 (AP-1)/cAMP-responsive element (CRE)-like, or NF-kappaB-like motifs within this region caused a reduction in the LPS response by 52%, 46%, and 51%, respectively. LPS induction of the proximal promoter-CAT reporter construct was reduced by >40% by the addition of 8-bromo-cAMP (8-Br-cAMP). To determine the role of the proximal promoter region in the context of the entire TNF-alpha gene, we produced a hemagglutinin (HA)-tagged genomic TNF-alpha construct that contains a deletion of the proximal promoter region. Transfection of this construct into RAW 264.7 cells demonstrated a decrease in LPS-induced transcripts as well as a lack of response to cAMP. This suggested an essential role for this regulatory region in LPS-induced activation and cAMP inhibition of mouse TNF-alpha gene transcription in murine macrophages.
 ...
PMID:The proximal promoter region is essential for lipopolysaccharide induction and cyclic AMP inhibition of mouse tumor necrosis factor-alpha. 1206 Apr 92