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Transcriptional regulation of drug efflux genes by EvgAS, a two-component system in Escherichia coil

Authors :
Eguchi, Yoko
Oshima, Taku
Mori, Hirotada
Aono, Rikizo
Yamamoto, Kaneyoshi
Ishihama, Akira
Utsumi, Ryutaro
Source :
Microbiology. Oct, 2003, Vol. 149 Issue 10, p2819, 10 p.
Publication Year :
2003

Abstract

A constitutively active mutant of histidine kinase sensor EvgS was found to confer multi-drug resistance (MDR) to an acrA-deficient Escherichia coil, indicating the relationship between the two-component system EvgAS and the expression of the MDR system. The observed MDR also depended on an outer-membrane channel, TolC. Microarray and S1 mapping assays indicated that, in the presence of this constitutive mutant ErgS, the level of transcription increased for some MDR genes, including the drug efflux genes emrKY, yhiUV, acrAB, mdfA and tolC. Transcription in vitro of emrK increased by the addition of phosphorylated EvgA. Transcription activation of tolC by the activated EvgS was, however, dependent on both EvgAS and PhoPQ ([Mg.sup.2+]-responsive two-component system), in agreement with the presence of the binding site (PhoP box) for the regulator PhoP in the tolC promoter region. Transcription in vitro of yhiUV also appears to require an as-yet-unidentified additional transcriptional factor besides EvgA. Taken together we propose that the expression of the MDR system is under a complex regulatory network, including the phosphorylated EvgA serving as the master regulator.

Details

Language :
English
ISSN :
13500872
Volume :
149
Issue :
10
Database :
Gale General OneFile
Journal :
Microbiology
Publication Type :
Academic Journal
Accession number :
edsgcl.110151373