title: A regulator that inhibits transcription by targeting an intersubunit interaction of the RNA polymerase holoenzyme.
abstract: The structures of the bacterial RNA polymerase holoenzyme have provided detailed information about the intersubunit interactions within the holoenzyme. Functional analysis indicates that one of these is critical in enabling the holoenzyme to recognize the major class of bacterial promoters. It has been suggested that this interaction, involving the flap domain of the beta subunit and conserved region 4 of the sigma subunit, is a potential target for regulation. Here we provide genetic and biochemical evidence that the sigma region 4/beta-flap interaction is targeted by the transcription factor AsiA. Specifically, we show that AsiA competes directly with the beta-flap for binding to sigma region 4, thereby inhibiting transcription initiation by disrupting the sigma region 4/beta-flap interaction.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Gregory
authors.forename: B E
authors.initials: BE
authors.lastname: Nickels
authors.forename: S J
authors.initials: SJ
authors.lastname: Garrity
authors.forename: E
authors.initials: E
authors.lastname: Severinova
authors.forename: L
authors.initials: L
authors.lastname: Minakhin
authors.forename: R J Bieber
authors.initials: RJ
authors.lastname: Urbauer
authors.forename: J L
authors.initials: JL
authors.lastname: Urbauer
authors.forename: T
authors.initials: T
authors.lastname: Heyduk
authors.forename: K
authors.initials: K
authors.lastname: Severinov
authors.forename: A
authors.initials: A
authors.lastname: Hochschild
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction / Q000379:methods; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: D021122:Protein Subunits; D011994:Recombinant Proteins; D012808:Sigma Factor; D012321:DNA-Directed RNA Polymerases