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)

We have studied the extrachromosomal maintenance and the transcription regulation of two glucocorticoid-inducible genes on bovine papilloma virus (BPV) vectors in c127 mouse fibroblasts. These genetic elements were the rat tryptophan oxygenase (TOase) gene promoter, which is active in vivo only in hepatocytes, and the long terminal repeat of the mouse mammary tumor virus (MMTV-LTR). From both genes, fusions of the 5'-flanking region of the transcription unit to the bacterial gene for chloramphenicol acetyltransferase (CATase) were constructed. These fusion genes were inserted either into pCGBPV9, a BPV vector encoding G418 resistance, into pBPV-BV1, a vector containing "stabilizing" segments of the human beta-globin gene, or into a BPV construct, whose bacterial plasmid sequences could be removed before transfection. Five constructs of the two latter groups, selectable in c127 cells only as foci, were normally maintained in the extrachromosomal state. In contrast, three out of five constructs based on pCGBPV9 and selectable for resistance against G418 were maintained in a high molecular weight form, most probably of intrachromosomal concatemeric nature, while the remaining two G418-resistant constructs appeared alternatively in this or the extrachromosomal monomeric form. In contrast to its absence of expression in fibroblasts in vivo, the TOase gene element present on BPV vectors was found to be active in fibroblasts in these transfection experiments. As judged by CATase activities and for TOase also by mapping of the transcription start sites, transcription of both genes was under hormonal regulation. All BPV vectors proved to be useful tools in the study of these regulated genes, and in only one out of ten constructs was regulation atypical, possibly due to effects from flanking vector sequences.
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PMID:Physical state, expression and regulation of two glucocorticoid-controlled genes on bovine papilloma virus vectors. 301 94

Transcription of the gene coding for tryptophan oxygenase (TO) in rat liver is induced 10-fold by glucocorticoids. To identify DNA elements mediating the glucocorticoid-regulated expression of the TO gene we transfected mouse L cells with a fusion gene consisting of 1.95 kb TO 5'-flanking sequences linked to the coding sequence of the gene for chloramphenicol acetyltransferase (CAT). CAT assay and RNA mapping experiments demonstrate that both transient and stable expression of the TO-CAT fusion gene are inducible by dexamethasone. Analysis of transcripts from 5'-deletion mutants identifies two glucocorticoid-responsive elements (GRE), located 450 bp and 1.2 kb upstream of the cap site. The purified rat glucocorticoid receptor binds to the sequence of each GRE as evidenced from footprinting experiments. Interestingly the protected sequence of the proximal footprint is by itself not sufficient for sequence induction, but requires sequences located immediately upstream.
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PMID:Glucocorticoid induction of the rat tryptophan oxygenase gene is mediated by two widely separated glucocorticoid-responsive elements. 358 68

To study the mechanism of steroid induced transcriptional control we have introduced recombinants of the chicken lysozyme gene and the rat tryptophan oxygenase (TO) gene into heterologous and homologous cells. To monitor the activity of the TO-promoter, 1.9 kb of the TO 5'-flanking sequences were fused with sequences coding for the bacterial enzyme chloramphenicol acetyltransferase (CAT). Upon transfer into mouse L-cells the transient expression of the TO-CAT recombinant was found to be inducible by dexamethasone. Transient expression of chicken lysozyme gene recombinants after introduction into various cell types could only be detected in chicken oviduct cells, or in conjunction with SV-40 enhancer sequences in human cells. The recombinant gene used in oviduct cells was a fusion between the lysozyme promoter, including 1.4 kb of upstream sequences, and the coding region of the gene for SV 40 T-antigen (plys-T). The expression in oviduct cells was stimulated by dexamethasone or progesterone, whereas SV 40 enhanced expression of lysozyme sequences in human cells could not be regulated by steroids. Using several deletion mutants, a region between -220 bp and -140 bp upstream of the cap site was found to be essential for both regulation by glucocorticoids as well as by progesterone.
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PMID:Steroid controlled expression of the chicken lysozyme and the rat tryptophan oxygenase gene after transfer into eukaryotic cells. 670 36