The Escherichia coli Regulator of Sigma 70 Protein, Rsd, Can Up-Regulate Some Stress-Dependent Promoters by Sequestering Sigma 70

Research output: Contribution to journalArticle


  • T Oshima
  • Sarah Piper
  • Christine Webster
  • LF Westblade
  • G Karimova
  • D Ladant
  • A Kolb

Colleges, School and Institutes


The Escherichia coli Rsd protein forms complexes with the RNA polymerase sigma(70) factor, but its biological role is not understood. Transcriptome analysis shows that overexpression of Rsd causes increased expression from some promoters whose expression depends on the alternative sigma(38) factor, and this was confirmed by experiments with lac fusions at selected promoters. The LP18 substitution in Rsd increases the Rsd-dependent stimulation of these promoter-lac fusions. Analysis with a bacterial two-hybrid system shows that the LP18 substitution in Rsd increases its interaction with sigma(70). Our experiments support a model in which the role of Rsd is primarily to sequester sigma(70), thereby increasing the levels of RNA polymerase containing the alternative sigma(38) factor.


Original languageEnglish
Pages (from-to)3489-3495
Number of pages7
JournalJournal of Bacteriology
Issue number9
Early online date2 Mar 2007
Publication statusPublished - 2 Mar 2007