Promoter-specific control of E. coli RNA polymerase by ppGpp and a general transcription factor.
The stringent response of Escherichia coli reflects a global influence of the nucleotide ppGpp on gene expression in response to nutrient starvation. For critical elements of the response, the target of ppGpp is RNA polymerase, which can be either repressed or activated in a promoter-dependent way. A small protein, DksA, which binds in the secondary channel of RNA polymerase, possibly along with other general regulatory factors, contributes to ppGpp-dependent transcription regulation. Rutherford and colleagues (pp. 236-248) identify mutations in genes for the core subunits of RNA polymerase that circumvent the need for DksA in the regulation; the sites of these mutations suggest that DksA acts allosterically through the RNA polymerase active site to destabilize transcription initiation complexes.
Roberts
Jeffrey W
JW
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA. jwr7@cornell.edu
D003067:Coenzymes / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006159:Guanosine Tetraphosphate / Q000378:metabolism*; D009154:Mutation; D011401:Promoter Regions, Genetic
D003067:Coenzymes; D029968:Escherichia coli Proteins; C090751:dksA protein, E coli; D006159:Guanosine Tetraphosphate; D012321:DNA-Directed RNA Polymerases