Molecular mechanism of negative autoregulation of Escherichia coli crp gene.
Transcription of the Escherichia coli crp gene encoding cAMP receptor protein (CRP) is negatively regulated by CRP-cAMP complex that binds to a specific site located downstream from the transcription start site. The binding of CRP-cAMP to this site activates transcription from a second divergent overlapping promoter. The mechanism of this negative autoregulation of the crp gene has been investigated by in vitro transcription, gel shift, DNase I footprinting, and exonuclease III protection assays. We demonstrated that the crp and divergent promoters are reciprocally and coordinately regulated by CRP-cAMP. The abortive initiation assay revealed that the divergent RNA itself is not required for the inhibition of crp transcription. Detailed binding studies revealed that CRP-cAMP stimulates the binding of RNA polymerase to the divergent promoter and thus blocks the occupation of the crp promoter by RNA polymerase.
Hanamura
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Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Aiba
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H
D001483:Base Sequence; D000242:Cyclic AMP / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008969:Molecular Sequence Data; D009876:Operon / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000502:physiology; D012329:RNA, Bacterial / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
D002373:Cyclic AMP Receptor Protein; D012329:RNA, Bacterial; D000242:Cyclic AMP; D012321:DNA-Directed RNA Polymerases