title: Functional map of the alpha subunit of Escherichia coli RNA polymerase: two modes of transcription activation by positive factors.
abstract: The role of the alpha subunit of Escherichia coli RNA polymerase in transcription activation by positive factors was investigated using two reconstituted mutant RNA polymerases (containing C-terminally truncated alpha subunits) and three positive factors [the cAMP receptor protein (CRP), OmpR, and PhoB]. The mutant RNA polymerases did not respond to transcription activation by activator proteins that bind upstream of the respective promoters. Transcription by these mutant enzymes was, however, activated in the cases where activators bind to target sites that overlap the promoter -35 region. Two different mechanisms are proposed for the positive control of transcription by activator proteins, one requiring the C-terminal domain of the alpha subunit, and the other not requiring it.
authors.affiliation: National Institute of Genetics, Department of Molecular Genetics, Shizuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
authors.forename: A
authors.initials: A
authors.lastname: Hanamura
authors.forename: K
authors.initials: K
authors.lastname: Makino
authors.forename: H
authors.initials: H
authors.lastname: Aiba
authors.forename: H
authors.initials: H
authors.lastname: Aiba
authors.forename: T
authors.initials: T
authors.lastname: Mizuno
authors.forename: A
authors.initials: A
authors.lastname: Nakata
authors.forename: A
authors.initials: A
authors.lastname: Ishihama
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D014157:Transcription Factors; C061278:PhoB protein, Bacteria; D012321:DNA-Directed RNA Polymerases