title: Global regulation of gene expression by OxyR in an important human opportunistic pathogen.
abstract: Most bacteria control oxidative stress through the H(2)O(2)-responsive transactivator OxyR, a member of the LTTR family (LysR Type Transcriptional Regulators), which activates the expression of defensive genes such as those encoding catalases, alkyl hydroperoxide reductases and superoxide dismutases. In the human opportunistic pathogen Pseudomonas aeruginosa, OxyR positively regulates expression of the oxidative stress response genes katA, katB, ahpB and ahpCF. To identify additional targets of OxyR in P. aeruginosa PAO1, we performed chromatin immunoprecipitation in combination with whole genome tiling array analyses (ChIP-chip). We detected 56 genes including all the previously identified defensive genes and a battery of novel direct targets of OxyR. Electrophoretic mobility shift assays (EMSAs) for selected newly identified targets indicated that ∼70% of those were bound by purified oxidized OxyR and their regulation was confirmed by quantitative real-time polymerase chain reaction. Furthermore, a thioredoxin system was identified to enzymatically reduce OxyR under oxidative stress. Functional classification analysis showed that OxyR controls a core regulon of oxidative stress defensive genes, and other genes involved in regulation of iron homeostasis (pvdS), quorum-sensing (rsaL), protein synthesis (rpsL) and oxidative phosphorylation (cyoA and snr1). Collectively, our results indicate that OxyR is involved in oxidative stress defense and regulates other aspects of cellular metabolism as well.
authors.affiliation: Department of Bioengineering Sciences, Research group Microbiology, VIB Department of Structural Biology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wei
authors.forename: Phu Nguyen Le
authors.initials: PN
authors.lastname: Minh
authors.forename: Andreas
authors.initials: A
authors.lastname: Dötsch
authors.forename: Falk
authors.initials: F
authors.lastname: Hildebrand
authors.forename: Warunya
authors.initials: W
authors.lastname: Panmanee
authors.forename: Ameer
authors.initials: A
authors.lastname: Elfarash
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schulz
authors.forename: Stéphane
authors.initials: S
authors.lastname: Plaisance
authors.forename: Daniel
authors.initials: D
authors.lastname: Charlier
authors.forename: Daniel
authors.initials: D
authors.lastname: Hassett
authors.forename: Susanne
authors.initials: S
authors.lastname: Häussler
authors.forename: Pierre
authors.initials: P
authors.lastname: Cornelis
mesh_terms: D001665:Binding Sites; D047369:Chromatin Immunoprecipitation; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D018085:Regulon; D013879:Thioredoxins / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*
chemical_list: C524857:OxyR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; D013879:Thioredoxins