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 minimal replicon of the 90,000 base-pair IncFII R plasmid NR1 consists of a 2700 base-pair region of the DNA. Minireplicator plasmids consisting of the 2700 base-pair minimal replicon plus a 2200 base-pair region coding for chloramphenicol acetyltransferase (cat) were used as templates for in vitro transcription. Six RNA transcripts were synthesized from these templates in vitro. We have determined the directions of transcription and the approximate sites of initiation and termination of each of the in vitro RNA transcripts. One RNA transcript was synthesized from the cat gene, while the other five were transcribed from the minimal replicon. Four of the RNA transcripts also were identified by quantitative hybridization of RNA synthesized in vivo from these minireplicator plasmids. The strengths of the promoters for the RNA transcripts were estimated by the relative rates of transcription both in vitro and in vivo. Transcription from convergent promoters reduced the rate of RNA synthesis in vivo in both directions. In vivo, a significant fraction of the cat mRNA was extended past its in vitro termination point. Transcription of mutants that have altered plasmid copy number and/or incompatibility properties also were examined. The possible roles of each of the transcripts as mRNA and their involvement in regulation of DNA replication are discussed.
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PMID:Transcription of the replication control region of the IncFII R-plasmid NR1 in vitro and in vivo. 258 99

The resistance plasmid NR1 derivative pRR330 consists of a neomycin-kanamycin resistance gene (neo-kan) flanked by directly repeated sequences of both insertion element IS1 DNA (768 base pairs) and 840 base pairs of DNA which are a part of the chloramphenicol acetyltransferase (cam) gene. Most Escherichia coli cell populations that were cultured in high neomycin concentrations carried plasmids whose neo-kan gene amplification was mediated either by IS1 DNA or by cam DNA as homologous recombination sites. This suggests that the final amplified cell populations were the descendants of a single cell.
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PMID:Recombination sites in plasmid drug resistance gene amplification. 299 83

A derivative of the R factor NR1 (called R12) has been isolated which undergoes an increased number of rounds of replication each division cycle in Proteus mirabilis, Escherichia coli, and Salmonella typhimurium. The alteration resulting in the increased number of copies (round of replication mutation) is associated with the transfer factor component of the R factor. R12 has the same drug resistance pattern as NR1, is the same size as shown by sedimentation in a sucrose gradient and electron microscopy (63 x 10(6) daltons), and has the same partial denaturation map. The level of the R factor gene product chloramphenicol acetyltransferase has been examined in P. mirabilis and was found to be consistent with gene dosage effects. The plasmid to chromosomal deoxyribonucleic acid ratio of NR1 increases several fold after entry into stationary phase, whereas this ratio for R12 remains approximately constant. Individual copies of R12 are selected at random for replication from a multicopy plasmid pool. A smaller percentage of R12 copies replicate during amino acid starvation than has previously been found for NR1 in similar experiments.
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PMID:Round of replication mutant of a drug resistance factor. 459 7

Three positive (PR1-3) and one negative (NR1) transcriptional control domain have been tentatively mapped in the promoter of the human F0F1-ATP synthase beta subunit gene (ATPsyn beta) in the context of expression in myogenic cells. Lipofection of promoter-chloramphenicol acetyltransferase fusion constructs into C2C12 myogenic cells revealed that two of the three positive domains (PR1 and PR2) function in both myoblasts and myotubes, whereas the third positive domain (PR3) and the sole negative domain (NR1) seem to function only in myotubes. PR1 contains a cluster of four CCAAT cis-elements, PR2 is a small 44-base pair region containing an SP1-like motif, and PR3 is a region previously shown to be recognized by both OXBOX- and REBOX-binding factors. By site-directed polymerase chain reaction linker mutations, the activity of the OXBOX/REBOX cis-element in myoblasts is shown to be masked by flanking sequences in PR3. The negative domain, NR1, is located between 300 and 1,000 base pairs upstream from the OXBOX/REBOX elements in a region containing multiple Alu repeats. Mobility gel shift analysis of DNA-protein complexes using competitor DNAs verified the involvement of both OXBOX- and REBOX-binding factors in PR3. Similar experiments show SP1-specific binding at PR2. These data with observations of OXBOX and REBOX-specific binding of an OXBOX/REBOX-like region within the conserved sequence block C of the human mitochondrial DNA D-loop sequence are consistent with the idea that OXBOX- and REBOX DNA-binding factors coordinate the expression of mitochondrial energy genes in highly oxidative tissues by working with well characterized general transcription factors such as SP1 and CCAAT DNA-binding proteins, which exist in the nucleus, and MTF, which exists in the mitochondrion.
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PMID:OXBOX and REBOX, overlapping promoter elements of the mitochondrial F0F1-ATP synthase beta subunit gene. OXBOX/REBOX in the ATPsyn beta promoter. 813 72

Nitrate increases the transcription of the two Arabidopsis thaliana nitrate reductase genes. We demonstrated previously that 238 and 330 bp of the 5' flanking regions, designated as NP1 and NP2, of the two nitrate reductase genes NR1 and NR2, respectively, are sufficient for nitrate-dependent transcription (Y. Lin, C.-F. Hwang, J.B. Brown, C.-L. Cheng [1994] Plant Physiol 106: 477-484). Here we identify the cis-acting elements of NP1 and NP2 that are necessary for nitrate-dependent transcription by linker-scanning (LS) analysis. In transgenic plants one LS mutant of NP1 and two LS mutants of NP2 exhibited significantly lower nitrate-induced reporter gene chloramphenicol acetyltransferase activity. To distinguish which of these three mutants lost nitrate inducibility, competitive reverse-transcriptase polymerase chain reaction was used to measure the chloramphenicol acetyltransferase mRNA levels before and after nitrate induction. The single LS mutant in NP1 lost its response to nitrate, whereas the two LS mutants in NP2 partially lost their response to nitrate. A 12-bp sequence is conserved between the NP1 site and the two NP2 sites. This sequence motif is also conserved in the 5' flanking regions of other nitrate-inducible plant genes. Gel mobility shift experiments indicate that these three regions bind to similar proteins. The binding is constitutive with respect to nitrate treatment and was observed in both nonphotosynthetic suspension cells and green leaves.
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PMID:Sequences necessary for nitrate-dependent transcription of Arabidopsis nitrate reductase genes. 908 75