Mechanism of transcriptional activation by FIS: Role of core promoter structure and DNA topology

Helge Auner, Malcolm Buckle, Annette Deufel, Tamara Kutateladze, Linda Lazarus, Ramesh Mavathur, Georgi Muskhelishvili*, Iain Pemberton, Robert Schneider, Andrew Travers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)

Abstract

The Escherichia coli DNA architectural protein FIS activates transcription from stable RNA promoters on entry into exponential growth and also reduces the level of negative supercoiling. Here we show that such a reduction decreases the activity of the tyrT promoter but that activation by FIS rescues tyrT transcription at non-optimal superhelical densities. Additionally we show that three different "up" mutations in the tyrT core promoter either abolish or reduce the dependence of tyrT transcription on both high negative superhelicity and FIS in vivo and infer that the specific sequence organisation of the core promoter couples the control of transcription initiation by negative superhelicity and FIS. In vitro all the mutations potentiate FIS-independent untwisting of the -10 region while at the wild-type promoter FIS facilitates this step. We propose that this untwisting is a crucial limiting step in the initiation of tyrT RNA synthesis. The tyrT core promoter structure is thus optimised to combine high transcriptional activity with acute sensitivity to at least three major independent regulatory inputs: negative superhelicity, FIS and ppGpp.

Original languageEnglish
Pages (from-to)331-344
Number of pages14
JournalJournal of Molecular Biology
Volume331
Issue number2
DOIs
Publication statusPublished - 8 Aug 2003
Externally publishedYes

Keywords

  • DNA supercoiling
  • FIS
  • Promoter structure
  • Transcription activation

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