Premium
Characterization of MarR family transcriptional regulator (BTH_I0021) from Burkholderia thailandensis
Author(s) -
SABRIN AFSANA,
Gupta Ashish,
Grove Anne
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1055.7
Subject(s) - efflux , biology , gene , burkholderia , electrophoretic mobility shift assay , biochemistry , genetics , gene expression , microbiology and biotechnology , bacteria
Burkholderia thailandensis , a soil dwelling bacterium, is a Gram‐negative bacillus, which is structurally similar to pathogenic species such as Burkholderia pseudomallei but a much less virulent species. B. thailandensis encodes nine Multiple antibiotic resistance Regulator (MarR) homologs, which act as transcriptional regulators of multiple genes, some of which may be involved in virulence and pathogenesis. The genomic locus of one of the MarR homologs, BTH_I0021 (BtMarR), predicts that it regulates the expression of both an EmrB/QacA family drug resistance transporter (BTH_I0022) and a Resistance Nodulation Division (RND) efflux pump (BTH_I0019). Increased expression of EmrB/QacA transporter and RND efflux systems have been associated with enhanced resistance to a wide variety of antimicrobials. Using Electrophoretic Mobility Shift Assays we have shown that BtMarR binds to the intergenic DNA of its own gene and a divergently oriented gene encoding a conserved hypothetical protein (BTH_I0020) of unknown subcellular localization. Upon treatment with inorganic and organic oxidants, SDS PAGE revealed the formation of reversible oligomeric species of BtMarR. DNA binding is attenuated by oxidized protein suggesting structural changes due to disulfide bond formation between redox‐active cysteines. PAR (4‐(2‐Pyridylazo) resorcinol) assay illustrated that this protein binds divalent metals such as zinc. This raises the possibility that BtMarR controls gene expression in response to oxidative stress via cysteine oxidation and by metal binding. Attenuation of DNA binding in presence of oxidants may lead to increased expression of efflux systems. Since oxidative stress is an important host defense mechanism, this study should shed light on the understanding of adaptive responses of Burkholderia strains towards the oxidative burst that characterizes the initial host response to bacterial infection. Support or Funding Information This work was supported by National Institutes of Health grant 1R15GM107825 (to Anne Grove)