CRP modulates fis transcription by alternate formation of activating and repressing nucleoprotein complexes.
The DNA architectural proteins FIS and CRP are global regulators of transcription in Escherichia coli involved in the adjustment of cellular metabolism to varying growth conditions. We have previously demonstrated that FIS modulates the expression of the crp gene by functioning as its transcriptional repressor. Here we show that in turn, CRP is required to maintain the growth phase pattern of fis expression. We demonstrate the existence of a divergent promoter in the fis regulatory region, which reduces transcription of the fis promoter. In the absence of FIS, CRP activates fis transcription, thereby displacing the polymerase from the divergent promoter, whereas together FIS and CRP synergistically repress fis gene expression. These results provide evidence for a direct cross-talk between global regulators of cellular transcription during the growth phase. This cross-talk is manifested in alternate formation of functional nucleoprotein complexes exerting either activating or repressing effects on transcription.
Nasser
W
W
Institut für Genetik und Mikrobiologie, Ludwig-Maximilians-Univesitaet, Maria-Ward-Strasse 1a, 80638 München, Germany.
Schneider
R
R
Travers
A
A
Muskhelishvili
G
G
D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D015964:Gene Expression Regulation, Bacterial; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D009698:Nucleoproteins / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; D009698:Nucleoproteins; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C440502:integration host factor, E coli