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Differential ability of σ s and σ 70 of Escherichia coli to utilize promoters containing half or full UP‐element sites
Author(s) -
Typas Athanasios,
Hengge Regine
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04382.x
Subject(s) - promoter , biology , rna polymerase , escherichia coli , protein subunit , housekeeping gene , sigma factor , sigma , microbiology and biotechnology , gene , genetics , physics , gene expression , quantum mechanics
Summary The σ s subunit of RNA polymerase (RNAP) is the master regulator of the general stress response in Escherichia coli . Nevertheless, the selectivity of promoter recognition by the housekeeping σ 70 ‐containing and σ 5 ‐containing RNAP holoenzymes (Eσ 70 and Eσ s respectively) is not yet fully clarified, as they both recognize nearly identical −35 and −10 promoter consensus sequences. In this study, we show that in a subset of promoters, Eσ s favours the presence of a distal UP‐element half‐site, and at the same time is unable to take advantage of a proximal half‐site or a full UP‐element. This is reflected by the frequent occurrence of distal UP‐element half‐sites in natural σ s ‐dependent promoters and the absence of proximal half‐sites. Eσ 70 , however, exhibits the opposite preference. The presence of the −35 element is a prerequisite for this differential behaviour. In the absence of the −35 element, half or full UP‐element sites play no role in sigma selectivity, but the distal subsite leads to an equivalent, if not greater, transcriptional stimulation than the proximal one for both sigma factors. Finally, experiments using single amino acid substitutions of σ s indicate that the foundation for this preference lies in an inability of σ s to interact with the a subunit C‐terminal domain.