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)

Expression from the promoter of the herpes simplex virus type 2 (HSV-2) large subunit of ribonucleotide reductase (ICP10) is stimulated by co-transfection with DNA that encodes the virion protein Vmw65 previously shown to activate in trans the transcription of all IE genes (Wymer et al., 1989). Specific cis response elements involved in ICP10 transcriptional regulation were studied by chloramphenicol acetyltransferase analysis with hybrid ICP10 promoter/CAT structural gene constructions containing wild type or site-directed mutations of the promoter sequences. The data indicate that Vmw65 activation requires an intact TAAT-GARAT motif while complex formation requires an intact Oct-1 element, and the AP-1 consensus elements in the ICP10 promoter are functional in vitro. Thus, expression from the wild type and GA-rich mutant constructions was enhanced 10-20-fold by co-transfection with DNA encoding Vmw65. The GARAT and POU homeobox (PHB) binding motifs were required for Vmw65 mediated activation but the mutant in the POU specific box (PSB) binding motif was activated at higher concentrations of Vmw65 DNA (1.0-3.0 micrograms). The PHB and PSB binding motifs were necessary for complex formation as determined by gel retardation analysis with in vitro synthesized OTF-1 and Vmw65 proteins. The GARAT and GA-rich elements were not required. CAT expression from pICP10-cat was enhanced by co-transfection with jun and fos encoding DNA, and the ICP10 promoter complexed with in vitro synthesized jun protein.
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PMID:Immediate early and functional AP-1 cis-response elements are involved in the transcriptional regulation of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10). 132 Jul 96

In an effort to determine whether homeobox genes modulate the activity of the promoter of the mouse neural cell adhesion molecule (N-CAM) gene, we have carried out a series of cotransfection experiments using NIH 3T3 cells. Plasmids were constructed containing Xenopus laevis Hox-2.5 and -2.4 coding sequences linked to a human cytomegalovirus promoter (CMV-Hox-2.5 and CMV-Hox-2.4). A 4.9-kilobase DNA fragment containing 5' flanking and first exon sequences of the mouse N-CAM gene was linked to a chloramphenicol acetyltransferase (CAT) reporter gene (N-CAM-Pro-CAT). Cotransfection with CMV-Hox-2.5 and N-CAM-Pro-CAT resulted in a strong induction of CAT activity. The N-CAM promoter contained two potential homeodomain binding sites (sites I and II) within a 47-base-pair segment (512-559 base pairs upstream of the ATG codon in the first exon of the N-CAM gene). This segment was linked to a minimal promoter (simian virus 40 early) and a downstream CAT gene. Although this construct was transcriptionally active at a low level in NIH 3T3 cells, cotransfection of CMV-Hox-2.5 resulted in CAT activity that was greatly elevated. Mutational studies revealed that it was the homeodomain binding site II sequence that was required for this regulation. In contrast, cotransfection with CMV-Hox-2.4 eliminated the CAT activity that was driven by the CMV-Hox-2.5 construct. Thus, the products of two related Hox genes, which are located adjacent to each other in the Hox-2 complex, can differentially modulate transcription from the promoter of a cell adhesion molecule gene. The results suggest that the N-CAM gene is likely to be a target for regulation by Hox gene products.
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PMID:Cell adhesion molecules as targets for Hox genes: neural cell adhesion molecule promoter activity is modulated by cotransfection with Hox-2.5 and -2.4. 134 44

Cytotactin is a morphoregulatory molecule of the extracellular matrix affecting cell shape, division, and migration that appears in a characteristic and complex site-restricted pattern during embryogenesis. The promoter region of the gene that encodes chicken cytotactin contains a variety of potential regulatory sequences. These include putative binding sites for homeodomain proteins and a phorbol 12-O-tetradecanoate 13-acetate response element (TRE)/AP-1 element, a potential target for transcription factors thought to be involved in growth-factor signal transduction. To determine the effects of homeobox-containing genes on cytotactin promoter activity, we conducted a series of cotransfection experiments on NIH 3T3 cells using cytotactin promoter-chloramphenicol acetyltransferase (CAT) reporter gene constructs and plasmids driving the expression of mouse homeobox genes Evx-1 and Hox-1.3. cotransfection with Evx-1 stimulated cytotactin promoter activity whereas cotransfection in control experiments with Hox-1.3 had no effect. To localize the sequences required for Evx-1 activation, we tested a series of deletions in the cytotactin promoter. An 89-base-pair region containing a consensus TRE/AP-1 element was found to be required for activation. An oligonucleotide segment containing this TRE/AP-1 site was found to confer Evx-1 inducibility on a simian virus 40 minimal promoter; mutation of the TRE/AP-1 site abolished this activity. To explore the potential role of growth factors in cytotactin promoter activation, chicken embryo fibroblasts, which are known to synthesize cytotactin, were first transfected with cytotactin promoter constructs and cultured under minimal conditions in 1% fetal bovine serum. Although the cells exhibited only low levels of CAT activity under these conditions, cells exposed for 12 h to 10% (vol/vol) fetal bovine serum showed a marked increase in CAT activity. Cotransfection with Evx-1 and cytotactin promoter constructs of cells cultured in 1% fetal bovine serum was sufficient, however, to produce high levels of CAT activity. These findings are consistent with the hypothesis that Evx-1, a homeobox-containing gene, may activate the cytotactin promoter by a mechanism involving a growth-factor signal transduction pathway. More generally, the results support the hypothesis that the place-dependent expression of morphoregulatory molecules may depend upon local cues provided by homeobox genes and their encoded proteins.
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PMID:Activation of the cytotactin promoter by the homeobox-containing gene Evx-1. 137 34

The ets oncogene superfamily consists of a family of sequence-specific DNA-binding proteins that activate transcription. We have previously identified two new members of the ets oncogene superfamily, namely elk-1 and elk-2. In this report we show that the recombinant elk-1 protein expressed in bacteria, like the c-ets-1 proto-oncogene, binds in a sequence-specific manner to Moloney murine sarcoma virus long terminal repeat, E74 target sequences and the PEA3 motif (polyoma enhancer), but does not bind to PU box sequences. Thus analysis of the DNA-binding specificity of ets-related proteins supports the view that different members show similar DNA-binding specificity, which is a general feature of the homeobox proteins. Our data using the chloramphenicol acetyltransferase gene linked to a thymidine kinase promoter containing multimers of the elk-1 target sequence indicates that elk-1 functions as a transcriptional activator. Interestingly, although elk-1 is the most divergent of all the members of the ets gene family, it shows very close similarities with c-ets-1 in some of its sequence-specific DNA-binding specificities. Here, we propose a new function for the elk-1 gene to act as a transcriptional activator of retroviruses and DNA tumor viruses.
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PMID:A divergent ets-related protein, elk-1, recognizes similar c-ets-1 proto-oncogene target sequences and acts as a transcriptional activator. 174 Nov 66

Previous studies have shown that in vitro expression of the neural cell adhesion molecule (N-CAM) can be regulated by the products of homeobox genes HoxB9, -B8, and -C6. N-CAM is a Ca(2+)-independent immunoglobulin-related CAM that plays an important role in neural development. In the present study, we investigated whether the liver cell adhesion molecule (L-CAM) a member of the Ca(2+)-dependent CAM family (cadherins) is also regulated by homeobox-containing genes. In transient cotransfection experiments of NIH 3T3 cells, we observed that both HoxD9 and liver-enriched POU-homeodomain transcription factor, HNF-1, activated chloramphenicol acetyltransferase gene reporter constructs containing the L-CAM promoter and an enhancer present in the second intron of the chicken L-CAM gene. Using electrophoretic mobility-shift assays, we found that components of cell extracts from NIH 3T3 cells transfected with HoxD9 bound to a small region of the L-CAM enhancer having a consensus sequence that is a putative binding site for HNF-1. Components of extracts from the chicken hepatoma cell line LMH that had been transfected with an HNF-1 expression vector also bound to this same site. In nuclear run-on experiments with nuclei from LMH cells that were transfected with expression vectors for HoxD9 or HNF-1, L-CAM RNA levels were increased 33-fold and 4-fold respectively. Using the same run-on procedure, it was confirmed that nuclei prepared from normal embryonic chicken liver cells expressed the RNAs for HoxD9, HNF-1, and L-CAM. Taken together with previous observations, these data raise the possibility that homeobox-containing genes will have a widespread role in the place-dependent expression of CAMs belonging both to immunoglobulin-related and to cadherin families.
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PMID:Regulation in vitro of an L-CAM enhancer by homeobox genes HoxD9 and HNF-1. 791 99

Scores of homeobox gene-encoded transcription factors are expressed in a definite spatiotemporal pattern during embryogenesis and regulate a series of as yet unidentified target genes to help coordinate the morphogenetic process. We have suggested that homeobox gene products modulate the expression of adhesion molecule genes and have shown in cotransfection experiments that the promoters for the neural cell adhesion molecule (N-CAM) and cytotactin/tenascin genes respond to cues from different homeobox-containing genes. In this study, we show that the HoxC6 (Hox-3.3)-encoded homeoprotein binds to a DNA sequence in the N-CAM promoter CCTAATTATTAA, designated homeodomain binding site I (HBS-I). To test whether HoxC6 regulated N-CAM promoter activity, we cotransfected the Long and Short reading frame variants of Xenopus HoxC6 (CMV-HoxC6-L and CMV-HoxC6-S) driven by the human cytomegalovirus (CMV) promoter together with a chloramphenicol acetyltransferase (CAT) reporter gene driven by the mouse N-CAM promoter (N-CAM-Pro-CAT). Cotransfection of NIH 3T3 cells with either of the CMV-HoxC6 expression vectors stimulated N-CAM promoter-driven CAT expression. A 47-bp region from the N-CAM promoter that included HBS-I and an adjacent potential HBS, HBS-II, conferred HoxC6 regulation on a simian virus 40 minimal promoter. HBS-I was sufficient for transactivation of the minimal promoter by CMV-HoxC6-S. However, transcriptional activation by CMV-HoxC6-L required both HBS-I and HBS-II, inasmuch as mutation of either HBS-I, HBS-II, or both motifs abolished the response. These studies suggest that HBS-I is a target site for binding and transcriptional control of the N-CAM promoter by homeoproteins, although accessory DNA sequences (such as HBS-II) may also be required. Together with previous studies, these results support the notion that N-CAM gene expression may be controlled by different combinations of homeoproteins that appear in a place-dependent manner during embryogenesis.
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PMID:Binding and transcriptional activation of the promoter for the neural cell adhesion molecule by HoxC6 (Hox-3.3). 839 70

To study the transcriptional regulation of the rat bone sialoprotein (BSP) gene, the nucleotide sequence of a approximately 1 kb HindIII/KpnI subfragment from a genomic clone containing the 5' flanking sequence, exon 1 and part of intron 1 was determined and the transcription start site defined. This region includes an inverted TATA element (nt -24 to -19), an inverted CCAAT box, a homeobox-binding site, a putative 1,25-dihydroxyvitamin D3 response element (VDRE) sequence overlapping the inverted TATA sequence, and a novel 18 nt palindrome that may control the tissue-specific transcription of the BSP gene. The shortest promoter sequence capable of directing bacterial chloramphenicol acetyltransferase reporter gene expression included the inverted TATA element and the inverted CCAAT box. However, the promoter activity was down-regulated by 1,25-dihydroxyvitamin D3, indicating that the unique VDRE-like sequence overlapping the TATA element is functional. Thus the rat BSP gene promoter is characterized by novel cis-acting elements that may be involved in hormone- and tissue-specific regulation of transcription.
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PMID:Cloning and characterization of the rat bone sialoprotein gene promoter. 843 61