Publication: Transcriptional profiles of Burkholderia pseudomallei reveal the direct and indirect roles of Sigma E under oxidative stress conditions
Issued Date
2014
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eng
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Mahidol University
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BioMed Central
Bibliographic Citation
BMC Genomics. Vol. 15, (2014), 787
Suggested Citation
Siroj Jitprasutwit, Ong, Catherine, Niramol Juntawieng, Wen Fong Ooi, Hemsley, Claudia M., Paiboon Vattanaviboon, Titball, Richard W., Tan, Patrick, Sunee Korbsrisate Transcriptional profiles of Burkholderia pseudomallei reveal the direct and indirect roles of Sigma E under oxidative stress conditions. BMC Genomics. Vol. 15, (2014), 787. doi:10.1186/1471-2164-15-787 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/2657
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Title
Transcriptional profiles of Burkholderia pseudomallei reveal the direct and indirect roles of Sigma E under oxidative stress conditions
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Abstract
Background: Burkholderia pseudomallei, the causative agent of melioidosis, is a Gram-negative bacterium widely
distributed in soil and water in endemic areas. This soil saprophyte can survive harsh environmental conditions,
even in soils where herbicides (containing superoxide generators) are abundant. Sigma factor E (σE) is a key
regulator of extra-cytoplasmic stress response in Gram-negative bacteria. In this study, we identified the B. pseudomallei
σE regulon and characterized the indirect role that σE plays in the regulation of spermidine, contributing to the
successful survival of B. pseudomallei in stressful environments.
Results: Changes in the global transcriptional profiles of B. pseudomallei wild type and σE mutant under physiological
and oxidative stress (hydrogen peroxide) conditions were determined. We identified 307 up-regulated genes under
oxidative stress condition. Comparison of the transcriptional profiles of B. pseudomallei wild type and σE mutant under
control or oxidative stress conditions identified 85 oxidative-responsive genes regulated by σE,
including genes involved in cell membrane repair, maintenance of protein folding and oxidative stress response and
potential virulence factors such as a type VI secretion system (T6SS). Importantly, we identified that the speG gene,
encoding spermidine-acetyltransferase, is a novel member of the B. pseudomallei σE regulon. The expression of speG
was regulated by σE, implying that σE plays an indirect role in the regulation of physiological level of spermidine to
protect the bacteria during oxidative stress.
Conclusion: This study identified B. pseudomallei genes directly regulated by σE in response to oxidative stress and
revealed the indirect role of σE in the regulation of the polyamine spermidine (via regulation of speG) for bacterial cell
protection during oxidative stress. This study provides new insights into the regulatory mechanisms by which σE
contributes to the survival of B. pseudomallei under stressful conditions.