PMID:8808945
| Citation |
Neely, MN and Olson, ER (1996) Kinetics of expression of the Escherichia coli cad operon as a function of pH and lysine. J. Bacteriol. 178:5522-8 |
|---|---|
| Abstract |
The Escherichia coli cadBA genes are regulated at the transcriptional level by external pH and lysine. The membrane-localized CadC protein is required for activation of this operon under inducing conditions, which include acidic external pH, lysine, and oxygen limitation. To better understand the mechanism by which CadC functions, the kinetics of cadBA expression as a function of pH and lysine were examined. By primer extension assays, cadBA expression was detected within 4 min following exposure of cells to one of the inducing stimuli (low pH or lysine), provided that the cells had first been grown to steady state in the presence of the other inducing stimulus. The induction time was three to four times longer when both inducing stimuli were added simultaneously. cadBA expression was shut off within 4 min following a shift from acidic to neutral pH. Treatment of cells with chloramphenicol prevented induction by acidic pH and lysine. Transcription of lysP (encodes a lysine transporter) was also examined, since it is a negative regulator of cadBA expression in the absence of lysine. lysP expression was repressed by lysine but not influenced by pH. Putative transcription start sites for lysP and cadC were determined. Together, these data suggest that CadC senses the lysine- and pH-induced signals separately and that one of the roles of lysine in inducing cadBA may be to repress expression of lysP, thus eliminating the repressing effects of LysP. |
| Links | |
| Keywords |
Amino Acid Transport Systems; Amino Acid Transport Systems, Basic; Antiporters; Bacterial Proteins/biosynthesis; Base Sequence; Carboxy-Lyases/biosynthesis; Chloramphenicol/pharmacology; Escherichia coli/genetics; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Hydrogen-Ion Concentration; Kinetics; Lysine/metabolism; Membrane Transport Proteins/biosynthesis; Molecular Sequence Data; Operon; Protein Synthesis Inhibitors; Saccharomyces cerevisiae Proteins; Signal Transduction |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.