The interaction between σ70 and the β-flap of Escherichia coli RNA polymerase inhibits extension of nascent RNA during early elongation

Bryce E. Nickels, Sean J. Garrity, Vladimir Mekler, Leonid Minakhin, Konstantin Severinov, Richard H. Ebright, Ann Hochschild

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)

Abstract

The σ-subunit of bacterial RNA polymerase (RNAP) is required for promoter-specific transcription initiation. This function depends on specific intersubunit interactions that occur when σ associates with the RNAP core enzyme to form RNAP holoenzyme. Among these interactions, that between conserved region 4 of σ and the flap domain of the RNAP β-subunit (β-flap) is critical for recognition of the major class of bacterial promoters. Here, we describe the isolation of amino acid substitutions in region 4 of Escherichia coli σ70 that have specific effects on the σ70 region 4/β-flap interaction, either weakening or strengthening it. Using these σ70 mutants, we demonstrate that the σregion 4/β-flap interaction also can affect events occurring downstream of transcription initiation during early elongation. Specifically, our results provide support for a structure-based proposal that, when bound to the β-flap, σ region 4 presents a barrier to the extension of the nascent RNA as it emerges from the RNA exit channel. Our findings support the view that the transition from initiation to elongation involves a staged disruption of σ-core interactions.

Original languageEnglish
Pages (from-to)4488-4493
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume102
Issue number12
DOIs
Publication statusPublished - 22 Mar 2005
Externally publishedYes

Keywords

  • σ region 4
  • Bacteriophage λ
  • P
  • Promoter escape
  • Transcription

Fingerprint

Dive into the research topics of 'The interaction between σ70 and the β-flap of Escherichia coli RNA polymerase inhibits extension of nascent RNA during early elongation'. Together they form a unique fingerprint.

Cite this