title: Selectivity of the Escherichia coli RNA polymerase E sigma 38 for overlapping promoters and ability to support CRP activation.
abstract: A series of gal promoter mutants has been used to compare the in vitro selectivities of the two forms of Escherichia coli RNA polymerase, E sigma 38 and E sigma 70. In the absence of the CRP-cAMP complex, E sigma 38 shows a strong preference for the ga/P1 promoter, whereas E sigma 70 preferentially initiates transcription from the ga/P2 promoter. E sigma 38 selectivity is not affected by the nature and position of the upstream sequences or by the phasing between synthetic upstream curved sequences and the -10 regions. In fact, all effects of mutations in the extended -10 region can be accounted for without evoking strong new sequence preferences for E sigma 38. Finally, both E sigma 38 and E sigma 70 initiate transcription from the ga/P1 promoter in the presence of CRP-cAMP complex and support direct cAMP-CRP activation at several CRP-dependent promoters.
authors.affiliation: Unité de Physicochimie des Macromolécules Biologiques, URA 1149 du CNRS, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Kolb
authors.forename: D
authors.initials: D
authors.lastname: Kotlarz
authors.forename: S
authors.initials: S
authors.lastname: Kusano
authors.forename: A
authors.initials: A
authors.lastname: Ishihama
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D000242:Cyclic AMP / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D002373:Cyclic AMP Receptor Protein; D004269:DNA, Bacterial; D009838:Oligodeoxyribonucleotides; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D000242:Cyclic AMP