title: Coactivation of the RpoS-dependent proP P2 promoter by fis and cyclic AMP receptor protein.
abstract: The Escherichia coli proP P2 promoter, which directs the expression of an integral membrane transporter of proline, glycine betaine, and other osmoprotecting compounds, is induced upon entry into stationary phase to protect cells from osmotic shock. Transcription from the P2 promoter is completely dependent on RpoS (sigma(38)) and Fis. Fis activates transcription by binding to a site centered at -41, which overlaps the promoter, where it makes a specific contact with the C-terminal domain of the alpha subunit of RNA polymerase (alpha-CTD). We show here that Fis and cyclic AMP (cAMP) receptor protein (CRP)-cAMP collaborate to activate transcription synergistically in vitro. Coactivation both in vivo and in vitro is dependent on CRP binding to a site centered at -121.5, but CRP without Fis provides little activation. The contribution by CRP requires the correct helical phasing of the CRP site and a functional activation region 1 on CRP. We provide evidence that coactivation is achieved by Fis and CRP independently contacting each of the two alpha-CTDs. Efficient transcription in vitro requires that both activators must be preincubated with the DNA prior to addition of RNA polymerase.
authors.affiliation: Department of Biological Chemistry, UCLA School of Medicine, Los Angeles, California 90095-1737, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: McLeod
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: R C
authors.initials: RC
authors.lastname: Johnson
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism*; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004357:Drug Synergism; D004591:Electrophoresis, Polyacrylamide Gel; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000378:metabolism*; D027981:Symporters; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; C079244:ProP protein, E coli; D012808:Sigma Factor; D027981:Symporters; C069567:sigma factor KatF protein, Bacteria; D012321:DNA-Directed RNA Polymerases