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)

Lipofection, a recently-developed method for gene transfer, was tested in secretory epithelial cells. Lipofection facilitated both transient DNA transfection with plasmids containing the chloramphenicol acetyltransferase gene and stable transfection with a plasmid containing the neomycin resistance gene, which confers resistance to the antibiotic G418 (Geneticin). Gene transfer occurred efficiently in a rabbit kidney medullary thick ascending limb cell line and in primary cultures of rabbit tracheal epithelial cells. The method was also effective in Simian virus 40-transformed human airway cells isolated from a normal individual and from a patient with cystic fibrosis (CF). Cytotoxicity was minimal, particularly when the time of exposure to the lipofectin-DNA was limited to 3-5 h (less than 5% cell loss). Thus, the lipofection method is useful for gene transfer in a variety of secretory epithelial cells and should be ideal for studies of defective secretory epithelial cell function in CF.
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PMID:Gene transfer by lipofection in rabbit and human secretory epithelial cells. 259 76

Upstream sequences of the human P450IA1 gene were inserted into a promoterless expression vector (pSVO-cat) containing the chloramphenicol acetyltransferase (CAT) gene, with and without the Harvey murine sarcoma virus (Ha-MSV) core enhancer, and either plasmid was transfected into human breast carcinoma MCF-7 and MDA-231 and mouse hepatoma Hepa-1 cell lines. In most instances constitutive and inducible CAT activities in the transient CAT expression assay were similar (within 3-fold) to those in the stable transformation CAT assay (selection of G418-resistant colonies following co-transfection with pSV2-neo). In the case of Ha-MSV-containing constructs stably integrated in the two human breast cancer lines, however, CAT expression was more than two orders of magnitude greater than that transiently expressed in these cells. Since the major difference between these two assays is plasmid copy number, these data suggest the presence of limiting amounts of tissue-specific positive-control enhancer-binding factor(s) in the breast carcinoma cell lines.
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PMID:Human P45IA1 upstream regulatory sequences expressing the chloramphenicol acetyltransferase gene. Effect of Ha-MSV enhancer and comparison of transient with stable transformation assays. 282 73

Primary human skin fibroblasts are an accessible source of phenotypically and karyotypically normal human cells, but are difficult to transfect with exogenous DNA. Here we demonstrate that both transient expression and stable transformation can be carried out by the method of electroporation. Highly efficient transient chloramphenicol acetyltransferase expression was shown after transfection with plasmid pRSVCAT. Stable transformation of human skin fibroblasts to G418 resistance was obtained after electroporation with neo-containing plasmids at an efficiency of approximately 1.4 x 10(-5)/micrograms DNA. The ability to easily transfect these cells with exogenous DNA may have important applications in the study of human genetic diseases and cancer.
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PMID:Transfection of primary human skin fibroblasts by electroporation. 285 91

The ability of recombinant DNA viruses to transfer genes into hematopoietic cells has been explored. A recombinant simian virus 40 (SV40) in which the early region had been replaced with the chloramphenicol acetyltransferase (CAT) gene driven by the promoter from Rous sarcoma virus (RSV), was constructed. This virus transferred the CAT gene more efficiently into mouse and human bone marrow cells and into the K562, MEL, and WEHI hematopoietic tissue culture cell lines, than the classical calcium phosphate DNA transfer procedure, as shown by assay for CAT activity 48 hr after infection. Recombinant SV40 virions were also shown to be capable of stably transforming Chinese hamster ovary cells by use of an early region recombinant containing the methotrexate-resistant dihydrofolate reductase (DHFR) gene driven by the RSV promoter. The entire DHFR transcriptional unit could be detected in the genome of transformed cells that were also shown to be resistant to methotrexate. A recombinant adenovirus stock containing the neomycin-resistance gene driven by the SV40 early promoter was used to infect the K562 and MEL hematopoietic cell lines to resistance to the antibiotic G418. Transformation frequency was 10- to 100-fold higher than that obtained with calcium phosphate-precipitated DNA. Most or all of the recombinant adenovirus genome was integrated as 1-3 copies in the transformed cells. These studies show the feasibility of using DNA viruses for introduction of new genetic material into hematopoietic cells.
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PMID:Transfer of genes into hematopoietic cells using recombinant DNA viruses. 298 41

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known to interact with a cytosolic receptor and, in turn, activate transcription of the mouse P1(450) gene. Various lengths of DNA upstream of the P1(450) gene were inserted into the pSV0-cat expression vector, with and without addition of the Harvey murine sarcoma virus (Ha-MSV) 72-bp repeat enhancer element. The constructs were cotransfected with pSV2-neo into mouse hepatoma wild-type cells and two variant cell lines. One variant is believed to result from a mutation in the P1(450) structural gene and expresses high levels of P1(450) mRNA constitutively; the other variant has a defect in nuclear translocation of the inducer-receptor complex. After selection in G418, the cells were treated with control medium, TCDD, cycloheximide, or TCDD plus cycloheximide and then assayed for chloramphenicol acetyltransferase (CAT) activity. The data are consistent with the presence of several functional regions within the upstream sequence: a promoter region, a region that is negatively autoregulated, possible repressor-binding and inducer-receptor complex-binding sites, and an upstream activation element that is required for transcriptional activation by TCDD. The Ha-MSV enhancer can substitute for this upstream activation element.
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PMID:Autoregulation plus upstream positive and negative control regions associated with transcriptional activation of the mouse P1(450) gene. 299 46

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

We have developed a modified, reproducible, and efficient method for introducing cloned genes into mammalian cells by using an electric field followed by treatment with sodium butyrate. Transfection frequencies with plasmid pSV2-neo, consisting of an antibiotic (G418) resistance gene and simian virus 40 (SV40) early promoter, by electroporation were higher than those by calcium phosphate DNA precipitation. Treatment with sodium butyrate following electroporation significantly increased the frequency of transfection in various types of cell lines and primary cultured cells including human skin fibroblasts. Treatment with sodium butyrate also increased the transient expression of the gene for chloramphenicol acetyltransferase (acetyl-CoA; chloramphenicol O3-acetyltransferase, CAT, EC 2.3.1.28) when the gene was introduced into BALB/c 3T3 cells by electroporation. Electroporation combined with sodium butyrate treatment is an improved method for stable and transient biochemical transformation of foreign genes in cultured mammalian cells.
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PMID:An improved method of electroporation for introducing biologically active foreign genes into cultured mammalian cells. 340 76

The foreign chemical tetrachlorodibenzo-p-dioxin (TCDD) is known to interact with the aromatic hydrocarbon receptor and, in turn, activate transcription of the mouse P1450 and P3450 genes. Various lengths of DNA upstream from the human P1450 gene were inserted into the promoterless pSVO-cat prokaryotic expression vector and compared with mouse P1450 upstream sequences similarly treated. The constructs were cotransfected with pSV2-neo into human, mouse, and monkey liver- and nonliver-derived cell lines. After selection in G418, the transformed colonies were treated with control medium, TCDD, or, in some cases, cycloheximide. Pooled transformants were then assayed for chloramphenicol acetyltransferase activity. The data are consistent with the presence of several functional regulatory regions within the upstream DNA: a promoter region, a region that is negatively autoregulated, and a region further upstream that activates transcription and is dependent upon a functional aromatic hydrocarbon receptor. Compared with 1604 base pairs of human P1450 upstream sequences, 1646 base pairs of mouse P1450 upstream sequences exhibit an increased sensitivity to TCDD; this effect was found to require both trans-acting protein factors and cis-acting DNA elements. Our results demonstrate the successful interaction of mouse trans-acting factors with human P1450 upstream sequences and human trans-acting factors with mouse P1450 upstream sequences.
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PMID:Comparison of human mouse P1450 upstream regulatory sequences in liver- and nonliver-derived cell lines. 345 96

A series of recombinant plasmid vectors containing hepatitis B virus (HBV) DNA sequences was constructed to study the biosynthesis of the hepatitis B virus surface antigen (HBsAg) RNA and to locate transcriptional control elements involved in the regulation of the S and pre-S DNA sequences. We examined the transcription of the HBsAg gene in permanent cell lines that were developed by transfecting with recombinant vectors containing HBV sequences and the neomycin gene followed by G418 selection. We further defined the promoter activities upstream of and within the pre-S sequences using the assayable chloramphenicol acetyltransferase gene. Results obtained from S1 nuclease digestion and primer extension suggest that HBsAg transcripts are initiated at multiple sites in the pre-S region and from a site upstream of the pre-S region. Chloramphenicol acetyltransferase assays indicate that DNA sequences within and upstream of the pre-S region contain promoter activities and that the "TATA" sequence-containing promoter and the internal promoter show similar levels of activities in CV-1 cells and several other cell lines tested.
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PMID:Transcriptional control elements of hepatitis B surface antigen gene. 345 53

The successful introduction of DNA into human bone marrow cells by electric field-mediated transfer was initially demonstrated by the detection of transient chloramphenicol acetyltransferase (acetyl-CoA:chloramphenicol O3-acetyltransferase, EC 2,3.1.28) activity in marrow cell extracts. To determine whether DNA was transferred into hematopoietic stem cells, human nucleated marrow cells were subjected to electroporation in the presence of a plasmid construct containing the bacterial genes conferring resistance to the neomycin analogue G418 (neo) and to mycophenolic acid (gpt). The growth of granulocyte/macrophage colonies in selective media, followed by hybridization analyses of resistant cells, established that DNA was transferred into human granulopoietic progenitor cells and was stably maintained and expressed in their differentiated progeny. Electroporation, therefore, offers the opportunity to transfer genes effectively into human hematopoietic stem cells and avoids some of the disadvantages associated with other methods of gene transfer.
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PMID:Stable expression of selectable genes introduced into human hematopoietic stem cells by electric field-mediated DNA transfer. 345 92


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