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The MarR‐type repressor MhqR (YkvE) regulates multiple dioxygenases/glyoxalases and an azoreductase which confer resistance to 2‐methylhydroquinone and catechol in Bacillus subtilis
Author(s) -
Töwe Stefanie,
Leelakriangsak Montira,
Kobayashi Kazuo,
Van Duy Nguyen,
Hecker Michael,
Zuber Peter,
Antelmann Haike
Publication year - 2007
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.1365-2958.2007.05891.x
Subject(s) - biology , repressor , bacillus subtilis , promoter , regulon , transcription factor , primer extension , transcription (linguistics) , genetics , dna footprinting , transcriptional regulation , operon , mutant , microbiology and biotechnology , gene , dna binding protein , gene expression , messenger rna , bacteria , linguistics , philosophy
Summary Catechol and 2‐methylhydroquinone (2‐MHQ) cause the induction of the thiol‐specific stress response and four dioxygenases/glyoxalases in Bacillus subtilis . Using transcription factor arrays, the MarR‐type regulator YkvE was identified as a repressor of the dioxygenase/glyoxalase‐encoding mhqE gene. Transcriptional and proteome analyses of the Δ ykvE mutant revealed the upregulation of ykcA ( mhqA ), ydfNOP ( mhqNOP ), yodED ( mhqED ) and yvaB ( azoR2 ) encoding multiple dioxygenases/glyoxalases, oxidoreductases and an azoreductase. Primer extension experiments identified σ A ‐type promoter sequences upstream of mhqA , mhqNOP , mhqED and azoR2 from which transcription is elevated after thiol stress. DNase I footprinting analysis showed that YkvE protects a primary imperfect inverted repeat with the consensus sequence of tATCTcgaAtTCgAGATaaaa in the azoR2 , mhqE and mhqN promoter regions. Analysis of mhqE ‐promoter– bgaB fusions confirmed the significance of YkvE binding to this operator in vivo . Adjacent secondary repeats were protected by YkvE in the azoR2 and mhqN promoter regions consistent with multiple DNA–protein binding complexes . DNA‐binding activity of YkvE was not directly affected by thiol‐reactive compounds in vitro . Mutational analyses showed that MhqA, MhqO and AzoR2 confer resistance to 2‐MHQ. Moreover, the Δ ykvE mutant displayed a 2‐MHQ and catechol resistant phenotype. YkvE was renamed as MhqR controlling a 2‐MHQ and catechol‐resistance regulon of B. subtilis .