Premium
Governor of the glnAp2 promoter of Escherichia coli
Author(s) -
Atkinson Mariette R.,
Pattarama Narinporn,
Ninfa Alexander J.
Publication year - 2002
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 - 10.1046/j.1365-2958.2002.03211.x
Subject(s) - activator (genetics) , enhancer , biology , transcription (linguistics) , promoter , microbiology and biotechnology , limiting , escherichia coli , gene , transcription factor , biochemistry , gene expression , mechanical engineering , linguistics , philosophy , engineering
Summary Low‐affinity sites for the activator NRI∼P (NtrC∼P) that map between the enhancer and the glnAp2 promoter were responsible for limiting promoter activity at high concentrations of NRI∼P in intact cells and in an in vitro transcription system consisting of purified bacterial components. That is, the low‐affinity sites constitute a ‘governor’, limiting the maximum promoter activity. As the governor sites are themselves far from the promoter, they apparently act either by preventing the formation of the activation DNA loop that brings the enhancer‐bound activator and the promoter‐bound polymerase into proximity or by preventing a productive interaction between the enhancer‐bound activator and polymerase. The combination of potent enhancer and governor sites at the glnAp2 promoter provides for efficient activation of the promoter when the activator concentration is low, while limiting the maximum level of promoter activity when the activator concentration is high.