Open AccessThe P1 promoter of the Escherichia coli rpoH gene is utilized by σ 70 ‐RNAP or σ S ‐RNAP depending on growth phase
Author(s) -
Janaszak Anna,
NadratowskaWesołowska Beata,
Konopa Grażyna,
Taylor Alina
Publication year - 2009
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01436.x
Subject(s) - rpos , sigma factor , promoter , rna polymerase , biology , microbiology and biotechnology , transcription (linguistics) , regulon , sigma , gene , gene expression , escherichia coli , genetics , physics , linguistics , philosophy , quantum mechanics
The P1 promoter of the Escherichia coli rpoH gene has been known as a σ 70 ‐dependent promoter (RNAP). We show here that it is also recognized by σ S . The σ 70 and σ S RNA polymerase subunits direct transcription from the P1 promoter in the exponential and stationary growth phases, respectively, and transcriptional start sites for the two holoenzymes differ by 1 nt. The transcription after heat shock is σ 70 ‐dependent. The results are based on (1) sequence analysis that revealed features of promoters responsive to both, σ 70 ‐ and σ S ‐RNAP, (2) in vitro transcription experiments verifying that both holoenzymes are able to transcribe the promoter, (3) electron microscopy results indicating that both holoenzymes bind the same site, (4) primer extension test performed with RNA isolated from the wild‐type and rpoS mutant strains, demonstrating that transcription from the P1 promoter in the stationary phase is σ S ‐dependent. These and previous results point to cooperation of σ 70 , σ 24 , σ S and σ 54 regulons in the expression of the rpoH gene, coding for the main regulator of the stress response, thus rendering it active in a variety of conditions.