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 isolated a new transposon, Tn2001, from the group P-2 plasmid Rms159-1 in Pseudomonas aeruginosa. Tn2001-encoded chloramphenicol resistance did not result from the formation of chloramphenicol acetyltransferase. Tn2001 was transposable between temperate phages and conjugative and nonconjugative plasmids belonging to various incompatibility groups, including P-1, P-3, P-4, P-5, P-7, and P-8 in P. aeruginosa. Transposition occurred independently of the general recombination ability of the Pseudomonas host, and its frequency varied between 10(-1) and 10(-8), depending upon the donor and recipient replicons. Tn2001 transposition also occurred in a recombination-deficient strain of Escherichia coli. Agarose gel electrophoresis and electron microscopic observations revealed that Tn2001 could transpose to different sites in the RP4 replicon and that the transposed deoxyribonucleic acid fragment was 2.1 kilobases long.
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PMID:Tn2001, a transposon encoding chloramphenicol resistance in Pseudomonas aeruginosa. 626 Jul 39

Salivary-specific and cAMP-inducible expression of the rat proline-rich protein gene RP4 is dependent on a 28-base pair sequence of a salivary-specific cAMP response element (SCRE) (Lin, H. H., and Ann, D. K. (1992) Gene Expression 2, 365-377). To unravel its trans-acting factor(s), we used double-stranded oligoprobes corresponding to the SCRE to screen a randomly primed lambda gt11 cDNA expression library made from RNA of rat salivary cells. In this report, we describe the cDNA cloning of these helix-loop-helix SCRE-binding proteins (SCBPs) and demonstrate that there are at least three isoforms in salivary cells, namely SCBP alpha, SCBP beta, and SCBP gamma. RNA polymerase chain reaction and sequence analyses further confirmed the existence of these three different SCBP isoforms, which code for putative proteins of 707, 706, and 682 amino acids, respectively. Expression of the cloned SCBP cDNAs in salivary cells stimulates the expression of a cotransfected reporter construct containing multicopies of the SCRE cloned upstream of the thymidine kinase promoter and the chloramphenicol acetyltransferase structural gene. This stimulation is much more pronounced in transfections in which SCBP alpha and SCBP beta are cotransfected than when they are transfected individually. Furthermore, when low concentrations of SCBP alpha and SCBP beta are cotransfected with the SCRE reporter gene, coexpression of the catalytic subunit of protein kinase A is required to efficiently activate the expression of the reporter gene. These results strongly suggest that the observed stimulation of the SCRE is achieved through the coordinated expression of the SCBP alpha, SCBP beta, and protein kinase A activities, perhaps via a direct association of the two SCBPs and their phosphorylation by protein kinase A. We conclude that the isolated SCBP alpha and SCBP beta cDNAs encode transcription activators that participate in the control of the inducible RP4 gene expression in salivary cells.
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PMID:The helix-loop-helix proteins (salivary-specific cAMP response element-binding proteins) can modulate cAMP-inducible RP4 gene expression in salivary cells. 768 70

A Tn5-derived mobile element has been constructed to identify genes and promoters related to pathogenesis and virulence in Pseudomonas syringae pv. phaseolicola. To enhance the rate of mutation this Tn5 derivative was constructed carrying a mutant transposase which was placed in cis to the transposable element, but just outside the inverted repeats, therefore eliminating secondary transposition and increasing the stability of the insertion. The new element also contains a promoterless cat (chloramphenicol acetyltransferase) gene as reporter to allow for positive selection of promoters being expressed under specific conditions. To facilitate cloning and manipulations in Escherichia coli, a ColE1 origin of replication has been included within the transposable element as well as the Mob region from the broad-host-range plasmid RP4, which allows this element to be efficiently mobilized by a triparental mating or by using an E. coli strain such as S17-1 to provide the tra functions. Sites for the rare cutters PacI and PmeI have also been included to facilitate locating the insertions on a PacI and/or PmeI physical map. This construction combines the properties of both a mobilizable plasmid and a transposon and therefore has been termed pTn5cat. It is almost the same size as the wild-type Tn5, 5877 bp, and has successfully been tested in P.s. phaseolicola and Xanthomonas campestris pv. campestris.
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PMID:pTn5cat: a Tn5-derived genetic element to facilitate insertion mutagenesis, promoter probing, physical mapping, cloning, and marker exchange in phytopathogenic and other gram-negative bacteria. 957 Nov 37