Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The LuxR regulatory protein of Vibrio harveyi as well as the autoinducer molecule, N-(3-hydroxybutanoyl) homoserine lactone, are known to be required for expression of luminescence. Although LuxR has been implicated in the activation of the promoter of the lux operon of V. harveyi, and can bind to two distinct sites upstream of the transcription initiation start site, its mode of action is unknown. In the present experiments, mobility shift assays were used to demonstrate that LuxR bound to the distal and proximal sites in an independent rather than co-operative interaction with a much tighter binding to the distal site. Deletion mutation analyses of DNA upstream of the lux promoter followed by transconjugation into V. harveyi in trans using the chloramphenicol acetyltransferase (cat) gene as a reporter demonstrated, however, that the proximal site for LuxR was absolutely critical for promoter activation while the distal LuxR site was only necessary for maximum activation. This result was confirmed by mutation of the proximal site which blocked activation of the lux promoter and binding of LuxR to this site, but did not prevent LuxR binding to the distal site.
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PMID:Proximal and distal sites bind LuxR independently and activate expression of the Vibrio harveyi lux operon. 783 May 70

In Pseudomonas aeruginosa, expression of the lasB gene which codes for the metalloprotease, elastase, depends on small diffusible N-acylhomoserine lactones. lasB expression is regulated through the interactions of N-3-oxododecanoyl-L-homoserine lactone and N-butanoyl-L-homoserine lactone with the transcriptional activators LasR and VsmR(RhlR), respectively. To investigate lasB expression further, we first located the transcriptional start site to a position 141 bp upstream from the translational start site. Using this information, we constructed a series of plasmids containing consecutive 5' deletions of the upstream region of lasB fused to a promoterless chloramphenicol acetyltransferase reporter gene. The results obtained indicate that three regions are required for efficient transcription of lasB; a 35 bp palindromic sequence located at +26 to +60 bp upstream from the translation start site, and two regions located upstream of the transcription start site, at -135 to -85 bp and -63 to -26 bp, respectively. Deletion of the latter region results in the loss of both N-butanoyl-L-homoserine lactone- and N-3-oxododecanoyl-L-homoserine lactone-mediated stimulation of lasB expression and provides further support for the role of this operator site as a target for either or both LasR and VsmR.
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PMID:Dissection of the promoter/operator region and evaluation of N-acylhomoserine lactone mediated transcriptional regulation of elastase expression in Pseudomonas aeruginosa. 901 Oct 52