The alarmone (p)ppGpp mediates physiological-responsive control at the sigma(54)-dependent Po promoter

Citation
Cc. Sze et V. Shingler, The alarmone (p)ppGpp mediates physiological-responsive control at the sigma(54)-dependent Po promoter, MOL MICROB, 31(4), 1999, pp. 1217-1228
Citations number
61
Categorie Soggetti
Microbiology
Journal title
MOLECULAR MICROBIOLOGY
ISSN journal
0950382X → ACNP
Volume
31
Issue
4
Year of publication
1999
Pages
1217 - 1228
Database
ISI
SICI code
0950-382X(199902)31:4<1217:TA(MPC>2.0.ZU;2-D
Abstract
Transcription from the Pseudomonas-derived sigma(54)- dependent Po promoter of the dmp operon is mediated by the aromatic-responsive regulator DmpR. H owever, physiological control is superimposed on this regulatory system cau sing silencing of the DmpR-mediated transcriptional response in rich media until the transition between exponential and stationary phase is reached. H ere, the positive role of the nutritional alarmone (p)ppGpp in DmpR regulat ion of the Po promoter has been identified and investigated in vivo, Overpr oduction of (p)ppGpp in a Pseudomonas reporter system was found to allow an immediate transcriptional response under normally non-permissive condition s. Conversely (p)ppGpp-deficient Escherichia coil strains were found to be severely defective in DmpR-mediated transcription, demonstrating the requir ement for this metabolic signal, A subset of mutations in the beta, beta' a nd om subunits of RNA polymerase, which confer prototrophy on ppGpp(0) E. c oil, was also found to restore specific DmpR-mediated transcription from Po , suggesting that the metabolic signal is mediated directly through the sig ma(54)-RNA polymerase. These data provide a direct mechanistic link between the physiological status of the cell and expression from sigma(54) promote rs.