Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Using Tn4431, a transposon that allows transcriptional fusions to a promoterless luciferase (lux) operon, we have isolated a nonpathogenic mutant of Xanthomonas campestris pv. campestris, i.e., JS111, that does not incite any of the black rot symptoms on all tested cruciferous host plants (J. J. Shaw, L. G. Settles, and C. I. Kado, Mol. Plant Microbe Interact. 1:39-45, 1988). In the study reported here, we determined that in contrast to the wild-type strain, JS111 is unable to induce a hypersensitive necrotic response on nonhost plants such as datura, tomato, and cucumber, suggesting that JS111 is a nonpathogenic, nonhypersensitive Hrp mutant. JS111 displayed culture growth rates, exopolysaccharide production, and protease, pectate lysase, cellulase, amylase, and phosphatase activities comparable to those of the wild-type strain. However, the growth of JS111 in host leaves was markedly attenuated. Coinoculation of JS111 with the wild-type strain in cauliflower or radish leaves rescued the growth deficiency of the mutant to normal levels. The locus mutated in JS111 was cloned and named hrpXc, and transcriptional and genetic complementation analyses of the hrpXc locus were conducted. The regulation of hrpXc expression was also investigated in vitro and in planta, using fusions to a lux or chloramphenicol acetyltransferase reporter gene. The hrpXc gene was found to be strongly induced in radish leaves. This is the first report and analysis of a hrp locus from a Xanthomonas species.
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PMID:A plant-inducible gene of Xanthomonas campestris pv. campestris encodes an exocellular component required for growth in the host and hypersensitivity on nonhosts. 216 73

Pancreatic amylase, chymotrypsin B, and trypsin I genes are specifically expressed in the exocrine pancreas. The 5'-flanking regions of these genes direct preferential expression of a linked reporter function (chloramphenicol acetyltransferase) in the pancreatic exocrine cell line AR4-2J. The sequences upstream of the amylase and chymotrypsin genes that are required for this cell specific activity possess the characteristics of transcriptional enhancers. We have mapped the regions responsible for enhancer activity by deletion analysis. Modification of specific nucleotide sequences within these regions can alter or eliminate enhancer function. Comparison of the 5'-flanking regions of nine genes expressed in the exocrine pancreas identifies a family of short related sequences. These sequences are located within the enhancer regions that we have mapped and may play a role in the regulation of the expression of pancreatic exocrine-specific genes.
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PMID:Cell-specific enhancers in the rat exocrine pancreas. 242 7

We injected circular forms of several different DNAs into fertilized eggs of Xenopus laevis, and studied the persistence and expression of the injected DNAs during early embryonic development. When we injected plasmids which contained Drosophila amylase genes, the copy number of the injected DNA increased only slightly during cleavage, started to decrease at the blastula stage, then became very small at the tadpole stage. In such embryos, Drosophila amylase activity was detected at and after the gastrula stage. When we injected other kinds of circular DNAs (pX1r101A, cDm2055, pII25.1, pBR322, and pSP-64-L14), their copy number did not increase throughout the early stages. When circular plasmids that contained bacterial chloramphenicol acetyltransferase (CAT) genes were injected, their copy number usually did not increase, but sometimes, for unknown reasons, it increased extensively throughout the blastula to gastrula stages. In both cases, CAT enzyme activity started to be expressed during the blastula to gastrula stages and disappeared at the 2 day-old tadpole stage. The level of CAT enzyme activity was roughly proportional to the amount of CAT mRNA formed, and also to the copy number of injected genes. From these results, we concluded that in Xenopus embryos, exogenously-injected circular DNAs are preserved for the most part as circular DNAs, and that the increase in their copy number within the embryos is not prerequisite for the expression of their genetic information.
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PMID:Persistence and expression of circular DNAs encoding Drosophila amylase, bacterial chloramphenicol acetyltransferase, and others in Xenopus laevis embryos. 247 99

Two distinct mouse amylase cDNAs, corresponding to the genes Amy-1.1 and Amy-1.2, have been isolated from a YBR/Ki parotid cDNA library. A cosmid clone containing the intact Amy-1.1 gene from strain YBR/Ki, including both the parotid and liver promoters, was transferred to the germ line of C57BL/6J mice. Two independent transgenic lines were produced. The transferred genes are organized as a 4-copy autosomal locus in line Tg518 and an 8-copy Y-linked locus in line Tg2736. Serum of both transgenic lines contained high levels of the AMY1B isozyme encoded by the transferred gene. Transcripts were detected in liver and, at a lower level, in several other tissues including white and brown fat. The anticipated expression in parotid was not observed. Constructs containing 270 or 540 bp of the 5' flanking region of the parotid promoter, cloned upstream of the chloramphenicol acetyltransferase (CAT) structural gene, were also not expressed in transgenic mice. The results suggest that sequences located more than 5 kb upstream of the Amy-1 parotid promoter and/or more than 10 kb downstream from the structural gene are required for parotid-specific expression. The results also demonstrate that non-parotid sources can produce a normal level of AMY1 in serum. Liver is the probable source of AMY1 in serum of these transgenic mice.
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PMID:A salivary amylase transgene is efficiently expressed in liver but not in parotid gland of transgenic mice. 247 16

The amyR2 allele of the Bacillus subtilis alpha-amylase cis-regulatory region enhances production of amylase and transcription of amyE, the structural gene, by two- to threefold over amyR1. The amylase gene bearing each of these alleles was cloned on plasmids of about 10 to 15 copies per chromosome. Transcription of the cloned amylase gene by each amyR allele was activated at the end of exponential growth and was subject to catabolite repression by glucose. The amount of amylase produced was roughly proportional to the copy number of the plasmid, and cells containing the amyR2-bearing plasmid, pAR2, produced two- to threefold more amylase than cells with the amyR1 plasmid, pAMY10. Deletion of DNA 5' to the alpha-amylase promoter, including deletion of the A + T-rich inverted repeat found in amyR1 and amyR2, had no effect on expression or transcription of alpha-amylase. Deletion of DNA 3' to the amyR1 promoter did not impair temporal activation of chloramphenicol acetyltransferase in amyR1-cat-86 transcriptional fusions, but catabolite repression was abolished. When an 8-base-pair linker was inserted in pAMY10 at the same site from which the 3' deletion was made, amylase expression doubled and was repressed less by glucose. Both the deletion and the insertion disrupted four bases at the 3' end of the putative amylase operator region. Site-directed mutagenesis was used to change bases in the promoter-operator region of amyR1 to their amyR2 counterparts. Either change alone increased amylase production twofold, but only the change at +7, next to the linker insertion of 3' deletion site, yielded the increased amylase activity in the presence of glucose that is characteristic of the amyR2 strain. The double mutant behaved most like strains carrying the amyR2 allele.
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PMID:Genetic analysis of the promoter region of the Bacillus subtilis alpha-amylase gene. 250 Apr 16

Eight eukaryotic promoters have been tested for their activity in vivo in Escherichia coli. The rat beta-actin, rat amylase, rat chymotrypsin B, mouse metallothionein I, rat insulin I, human insulin, Rous sarcoma virus long terminal repeat (RSV LTR) and hepatitis B viral precore promoter activities were measured by using the bacterial chloramphenicol acetyltransferase coding sequences as the reporter function and by primer extension RNA analysis. All eight promoter-chloramphenicol acetyltransferase constructs produce chloramphenicol acetyltransferase activity with the following relative strengths: RSV LTR greater than rat beta-actin greater than rat insulin I greater than rat amylase greater than hepatitis B virus precore greater than human insulin greater than rat chymotrypsin B greater than mouse metallothionein I. A primer extension analysis indicates that transcription from the RSV LTR, rat insulin I, and rat beta-actin promoters initiates at the sites expected for eukaryotic rather than prokaryotic promoters. Thus the site of initiation is determined by the DNA sequence rather than by the RNA polymerase.
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PMID:Eukaryotic promoters drive gene expression in Escherichia coli. 268 Nov 82

Two cis-acting elements, the enhancer and the promoter, independently contribute to the cell-specific expression of the rat insulin 1 gene. The activities of these elements are presumably mediated by trans-acting factors. We have performed intracellular competition experiments that suggest the presence of a negative factor(s) that represses the enhancer activity in cells that do not express the insulin gene. In these experiments fibroblast cells (COS-7) were transfected with two plasmids: a test plasmid containing the gene for chloramphenicol acetyltransferase under the control of the thymidine kinase promoter and the insulin enhancer; and a competitor plasmid containing insulin enhancer sequences and the simian virus 40 origin of replication to permit its replication in the recipient cells. The presence of the competitor plasmid led to a 5- to 6-fold increase in chloramphenicol acetyltransferase activity as compared with the activity detected when insulin enhancer was absent from either the competitor or the test plasmid. A 5-fold increase in chloramphenicol acetyltransferase activity was also seen when the rat amylase enhancer was present on the competitor plasmid; in contrast the simian virus 40 enhancer exerted no effect. Efficient derepression required additional sequences downstream from those essential for enhancer activity. We propose that the activity of the rat insulin 1 enhancer is modulated by a negative trans-acting factor(s) that is active in cells not expressing insulin but is overridden by the dominant positive trans-acting factor(s) present in insulin-producing cells.
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PMID:Regulation of rat insulin 1 gene expression: evidence for negative regulation in nonpancreatic cells. 351 53

Bacillus subtilis 168GR10 was shown to contain a mutation, gra-10, which allowed normal temporal activation of alpha-amylase synthesis in the presence of a concentration of glucose that is inhibitory to activation of amylase synthesis in the parent strain, 168. The gra-10 mutation was mapped by phage PBS-1-mediated transduction and by transformation to a site between lin-2 and aroI906, very tightly linked to amyE, the alpha-amylase structural gene. The gra-10 mutation did not pleiotropically affect catabolite repression of sporulation or of the synthesis of extracellular proteases or RNase and was unable to confer glucose-resistance to the synthesis of chloramphenicol acetyltransferase encoded by the cat-86 gene driven by the amyE promoter region (amyR1) inserted into the promoter-probe plasmid pPL603B. It therefore appears that gra-10 defines a cis-regulatory site for catabolite repression, but not for temporal activation, of amyE expression. The evidence shows that temporal activation and glucose-mediated repression of alpha-amylase synthesis in B. subtilis 168 are distinct phenomena that can be separated by mutation.
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PMID:Isolation and characterization of a cis-acting mutation conferring catabolite repression resistance to alpha-amylase synthesis in Bacillus subtilis. 391 91

Aeromonas hydrophila is an important pathogen of fish, and its high-virulence strains display a two-dimensional paracrystalline layer (S-layer) on their outermost surfaces. The nucleotide sequence of a 4.1-kb region located 700 bp upstream of the A. hydrophila TF7 S-layer protein gene (ahsA) has been determined. A sequence analysis of the region revealed the presence of three complete open reading frames ending in a gene encoding a 79.8-kDa polypeptide that shows high homology to the PulD family of secretion proteins. The sequenced region displays both organizational and sequence homology to the Xanthomonas campestris pv. campestris Xps secretory system. Insertional inactivation of the spsD (S-protein secretion D) gene showed that the loss of expression of the PulD homolog coincided with the localization of the S-protein in the periplasm and the loss of the S-layer from the surface of the bacterium. However, the secretion of the enzymes hemolysin, amylase, and protease was unaffected in the mutant with the nonfunctional spsD gene, as was the export of flagella and fimbrial proteins. Southern blot analysis showed that the spsD gene was not conserved among all strains of S-protein-producing A. hydrophila or Aeromonas veronii biotype sobria. Use of the promoterless chloramphenicol acetyltransferase gene showed that unlike pulD and its homologs, spsD contains its own promoter. A. hydrophila has been shown to contain the exe operon, which is responsible for the secretion of a number of extracellular enzymes in this bacterium. A fragment of DNA was generated from the exeD gene of A. hydrophilia Ah65 by PCR and was subsequently used in hybridization studies to probe the chromosome of A. hydrophila TF7. The presence of an exeD homolog in A. hydrophila TF7 was found; therefore, the spsD gene encodes a second pulD homolog that displays a high specificity for the secretion of the S-protein. This gene appears to be part of a second terminal branch of the general secretory pathway in A. hydrophila.
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PMID:A specific PulD homolog is required for the secretion of paracrystalline surface array subunits in Aeromonas hydrophila. 760 63

Production of inflammatory cytokines in the pancreas, lung, and liver is believed to play a major role in the development of severe pancreatitis. This tissue-specific production could lend itself to directed anti-cytokine gene therapy if an appropriate delivery system could be developed. This study was undertaken to examine a novel approach for the delivery of protein-based therapies to the tissues involved during acute pancreatitis. Healthy mice received an intraperitoneal injection of cationic liposomes and a DNA plasmid containing the chloramphenicol acetyltransferase (CAT) reporter gene. Animals were killed at 12 hours and 1, 2, 3, 7, and 14 days with serum, pancreas, lung, and liver harvested. Acute pancreatitis was induced (cerulein, 50 micrograms/kg/hr intraperitoneally x4) in additional mice before or after CAT transfection. The presence of pancreatitis was established in all animals by histologic scoring of pancreata and by serum amylase and lipase levels. CAT transfection efficiency was determined by quantitative CAT enzyme activity within tissue homogenates. Animals that received the liposome were successfully transfected with the CAT gene into the pancreas, lungs, and liver. Maximal transfection in each tissue occurred at 12 hours with decreasing CAT activity over the ensuing 14 days. No healthy animals receiving the CAT gene developed elevations in amylase, lipase, or any histologic parameter of pancreatitis. Transfection efficiency in the pancreas was markedly increased by preexisting or delayed induction of pancreatitis, whereas transfection of the lung and liver was increased to a lesser extent. Gene transfection into the pancreas, liver, and lungs is possible using a cationic liposome delivery system that does not induce pancreatitis or pancreatic inflammation. Pancreatic expression of the gene product is equal to or greater than that of the organs of the reticuloendothelial system and continues at very high efficiency rates during acute pancreatitis.
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PMID:Cationic liposome-mediated gene transfer during acute pancreatitis: tissue specificity, duration, and effects of acute inflammation. 984 74


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