Synergistic transcription activation: a dual role for CRP in the activation of an Escherichia coli promoter depending on MalT and CRP.
Activation of the Escherichia coli malEp promoter relies on the formation of a higher order structure involving cooperative binding of MalT to promoter-proximal and promoter-distal sites as well as CRP binding to three sites located in between. MalT is the primary activator and one function of CRP is to facilitate cooperative binding of MalT to its cognate sites by bending the intervening DNA. It is shown here that CRP also participates directly in malEp activation. This function is carried out by the molecule of CRP bound to the CRP site centered at -139.5 (CRP site 3). This molecule of CRP recruits RNA polymerase by promoting the binding of the RNA polymerase alpha subunit C-terminal domain (alphaCTD) to DNA immediately downstream from CRP site 3, via a contact between alphaCTD and activating region I of CRP. The action of MalT and CRP at malEp hence provides the example of a novel and complex mechanism for transcriptional synergy in prokaryotes whereby one activator both helps the primary activator to form a productive complex with promoter DNA and interacts directly with RNA polymerase holoenzyme.
Richet
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Unité de Génétique Moléculaire, URA CNRS 1773, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris Cedex 15, France. erichet@pasteur.fr
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism*; D018983:DNA Footprinting; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D003850:Deoxyribonuclease I; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D017930:Genes, Reporter; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C058976:MalT protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D014157:Transcription Factors; C461599:maltose transport system, E coli; D012321:DNA-Directed RNA Polymerases; D003850:Deoxyribonuclease I; D001616:beta-Galactosidase