Occlusion of RNA polymerase by oligomerization of DnaA protein over the dnaA promoter of Escherichia coli.
DnaA protein, the initiator protein for initiation of Escherichia coli chromosomal replication, has been shown to repress its own expression from two dnaA promoters, 1P and 2P. The sequence-specific binding of DnaA protein to the DnaA box, located between the two promoters, results in subsequent oligomerization of DnaA protein. Upon increasing the concentration of DnaA protein, the oligomerization proceeds to both dnaA promoters from the DnaA box and inhibits RNA polymerase binding to both promoters. This results in the repression of transcription, suggesting that the extent of oligomerization of DnaA proteins over two dnaA promoters contributes to the autoregulation of expression of the dnaA gene. When the two dnaA promoters were bound and repressed by DnaA protein, the interaction of RNA polymerase with IciA protein, which is a specific inhibitor of initiation of in vitro E. coli chromosomal replication, appeared to dissociate the oligomerized DnaA proteins from the 1P promoter and allowed RNA polymerase to be loaded for its transcription.
Lee
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YS
Institute for Molecular Biology and Genetics, Department of Microbiology, Seoul National University, Korea.
Hwang
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DS
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D003852:Deoxyribonucleoproteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D046911:Macromolecular Substances; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D003852:Deoxyribonucleoproteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; C068863:argP protein, E coli; D012321:DNA-Directed RNA Polymerases