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Control of rpoS transcription in Escherichia coli and Pseudomonas : why so different?
Author(s) -
Venturi Vittorio
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03547.x
Subject(s) - rpos , biology , sigma factor , transcriptional regulation , quorum sensing , pseudomonas fluorescens , escherichia coli , pseudomonas putida , transcription (linguistics) , regulator , autoinducer , regulation of gene expression , genetics , response regulator , tetr , stringent response , microbiology and biotechnology , post transcriptional regulation , pseudomonas aeruginosa , transcription factor , gene , bacteria , gene expression , promoter , rna polymerase , biofilm , repressor , mutant , linguistics , philosophy
Summary In Escherichia coli , the stationary phase alternative sigma factor σ s controls the expression of genes involved cell survival in response to cessation of growth (stationary phase) and provides cross‐protection to various stresses. Levels of σ s increase dramatically at the onset of stationary phase and are regulated at the transcriptional, post‐transcriptional and post‐translational level, making this one of the most complex regulatory systems in bacteria. The basic mechanisms for the control of translation and σ s proteolysis have been understood. However, studies on the transcriptional control in E. coli lag behind and are controversial. The cAMP‐CRP complex and the two component BarA/UvrY system have been implicated and, ppGpp and polyphosphate appear to have a signalling role. σ s has also been reported to be a general stress regulator in the fluorescent pseudomonads ( Pseudomonas aeruginosa , P. fluorescens and P. putida ) and recent studies on σ s regulation highlight that transcriptional regulation in these bacteria apparently plays a major role. Global regulatory systems, the GacA/GacS two component system and quorum sensing all affect rpoS expression, as does the TetR family PsrA regulator that directly binds to‐ and activates the rpoS promoter in stationary phase. This striking difference in regulation between E. coli and Pseudomonas can be partly attributed to the differences in the functional role of σ s in the two bacterial species. This report will review mainly recent studies on rpoS transcriptional regulation and will try to rationalize the current knowledge into a working model.