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 construction of a mammalian cell expression vector using human cytomegalovirus immediate early gene enhancer to initiate transcription of inserted coding sequences is described. The vector also carries Epstein-Barr virus EBNA-1 nuclear antigen gene, ori-P sequences and hygromycin B resistance gene hph from E. coli. The expression capacity of this construct was tested by inserting the chloramphenicol acetyltransferase (CAT) gene into the vector. The EBV-CAT construct was transfected into various cell lines and high levels of CAT activity were obtained in human and monkey cells. In these cells, the vector DNA also replicates as an extrachromosomal element having 1 to 20 copies per cell. In most cases, the vector copy number and the expression level of inserted gene was in positive correlation in different cell clones.
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PMID:An EBV-based mammalian cell expression vector for efficient expression of cloned coding sequences. 282 66

Two regions of the Epstein-Barr virus (EBV) genome together make up an element, oriP, which acts in cis to support plasmid replication in cells that express the EBV nuclear antigen 1 (EBNA-1). The two components of oriP are a region containing a 65-base-pair (bp) dyad symmetry and a region containing 20 copies of a 30-bp direct repeat. Here we show that the 30-bp family of repeats of oriP can function as a transcriptional enhancer that is activated in trans by the EBNA-1 gene product. In either EBV-genome-positive cells or in cells that express EBNA-1, the 30-bp family of repeats, when positioned in either orientation upstream or downstream, enhances expression of the chloramphenicol acetyltransferase (CAT) gene expressed from either the simian virus 40 early promoter or the herpes simplex virus type 1 thymidine kinase promoter. The extent of transcriptional enhancement varies with the promoter and cell type. This enhanced CAT expression reflects an increased level of CAT mRNA and does not result from amplification of the plasmids expressing CAT. In addition, plasmids carrying the gene for resistance to hygromycin B and the 30-bp family of repeats yielded 10 to 100 times more hygromycin B-resistant colonies than the vector lacking the 30-bp family of repeats in both EBV-genome-positive cells and cells that express EBNA-1. EBNA-1 is known to bind to sequences within the 30-bp family of repeats (D. R. Rawlins, G. Milman, S. D. Hayward, and G. S. Hayward, Cell 42:859-868, 1985), and these trans- and cis-acting elements together have at least two functional roles: (i) they are required for DNA replication dependent upon oriP, and (ii) they can enhance expression of genes linked to the 30-bp family of repeats of oriP.
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PMID:trans activation of an Epstein-Barr viral transcriptional enhancer by the Epstein-Barr viral nuclear antigen 1. 302 15

Eight transgenic mice were generated in which the promoter of the mouse alpha 2(I) collagen gene (nucleotides -2000 to +54), linked to the bacterial gene for chloramphenicol acetyltransferase (CAT), is stably integrated in the germ line. These strains contain from 1 to 20 copies of the alpha 2(I) collagen-CAT chimeric gene per haploid genome. In seven of the eight strains, the CAT gene is expressed, although the levels of CAT enzyme activity vary considerably from one strain to the other. In six of these strains, the expression of the CAT gene follows the expected tissue distribution pattern of expression of the alpha 2(I) collagen gene. In these six strains, the level of CAT activity is much higher in extracts of tail, a tissue that is very rich in tendons, than in any other tissue that was tested. This distribution parallels the much higher levels of alpha 2(I) collagen RNA that are found in the tail as compared to other tissues. Expression of the chimeric gene is detected in the embryo after 8.5 days of gestation, at approximately the same time that the endogenous type I genes become active. We conclude that the alpha 2(I) collagen promoter sequences present in the recombinant plasmid used for our experiments contain sufficient information to ensure stage- and tissue-specific activity of this promoter.
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PMID:Developmental and tissue-specific expression directed by the alpha 2 type I collagen promoter in transgenic mice. 345 66

To investigate the possible direct/indirect role of Human immunodeficiency virus (HIV) as a cofactor in human papillomavirus (HPV) oncogenesis, cotransfection experiments were carried out in which a recombinant plasmid containing the HPV16 long control region (LCR) linked to the chloramphenicol acetyltransferase (CAT) gene was cotransfected into cultured cells with a plasmid expressing HIV-1 Tat protein. Tat expression efficiency and transactivation activity were evaluated in different cell lines by cotransfecting plasmids containing the HIV tat gene and HIV LTR-driven CAT-coding sequences. HeLa and CaSki cell lines represented the most appropriate recipient cells for Tat-directed transactivation of both the HIV LTR and the HPV LCR promoters. Furthermore, HIV tat was transfected into HeLa cells (containing 10-20 copies per cell of HPV18), and HPV18 E7 protein expression was evaluated by a radioimmunoprecipitation assay using polyclonal antibodies against the E7 protein. Our results show that the Tat protein can transactivate the HPV LCR and increase HPV18 E7 expression in HeLa cells.
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PMID:Human immunodeficiency virus type 1 tat gene enhances human papillomavirus early gene expression. 829 82