AUTHOR=Pacheco Luis G., Castro Thiago L., Carvalho Rodrigo D., Moraes Pablo M., Dorella Fernanda A., Carvalho Natalia B., Slade Susan E., Scrivens James H., Feelisch Martin , Meyer Roberto , Miyoshi Anderson , Oliveira Sergio C., Dowson Christopher G., Azevedo Vasco A.

TITLE=A Role for Sigma Factor σE in Corynebacterium pseudotuberculosis Resistance to Nitric Oxide/Peroxide Stress

JOURNAL=Frontiers in Microbiology

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2012.00126

DOI=10.3389/fmicb.2012.00126

ISSN=1664-302X

ABSTRACT=<p>Pathogenic intracellular bacteria can respond to antimicrobial mechanisms of the host cell through transient activation of stress-responsive genes by alternative sigma (σ) factors of the RNA polymerase. We evaluated the contribution of the extracytoplasmic function sigma factor σ<sup>E</sup> for <italic>Corynebacterium pseudotuberculosis</italic> resistance to stress conditions resembling those found intracellularly during infection. A <italic>sigE</italic>-null mutant strain (Δ<italic>sigE</italic>) of this bacterium was more susceptible <italic>in vitro</italic> to acidic pH, cell surface stressors, and biologically relevant concentrations of nitric oxide (NO). The same mutant strain was unable to persist in C57BL/6 mice but remained infective in mice lacking inducible nitric oxide synthase (iNOS), confirming the significance of σ<sup>E</sup> for resistance to nitric oxide/peroxide stress <italic>in vivo</italic>. High-throughput proteomic analysis identified NO-responsive extracellular proteins of <italic>C. pseudotuberculosis</italic> and demonstrated the participation of σ<sup>E</sup> in composition of this bacterium’s exoproteome.</p>