Exploration of the Role of the Non-Coding RNA SbrE in L. monocytogenes Stress Response

• Main Authors: Sana Mujahid, Teresa M. Bergholz, Haley F. Oliver, Kathryn J. Boor, Martin Wiedmann
• Format: Article
• Language: English
• Published: MDPI AG 2012-12-01
• Series: International Journal of Molecular Sciences
• Subjects: non-coding RNA; Listeria monocytogenes; sigma B
• Online Access: http://www.mdpi.com/1422-0067/14/1/378

SbrE is a ncRNA in Listeria monocytogenes, reported to be up-regulated by the alternative sigma factor σB. Initial quantitative RT-PCR (qRT-PCR) experiments on parent strains and isogenic ΔsigB strains demonstrated σB-dependent expression of SbrE across the four L. monocytogenes lineages and in L. innocua. Microarray and proteomics (MDLC/MS/MS with iTRAQ labeling) experiments with the L. monocytogenes parent strain and an isogenic ΔsbrE strain identified a single gene (lmo0636) and two proteins (Lmo0637 and Lmo2094) that showed lower expression levels in the ΔsbrE strain. qRT-PCR demonstrated an increase in SbrE transcript levels in stationary phase L. monocytogenes and in bacteria exposed to oxidative stress (mean log2 transcript levels 7.68 ± 0.57 and 1.70 ± 0.71 greater than in mid-log phase cells, respectively). However, no significant differences in growth or survival between the parent strain and ΔsbrE strain were confirmed under a variety of environmental stress conditions tested. Our data suggest that σB-dependent transcription of SbrE represents a conserved mechanism that contributes, across Listeria species, to fine-tuning of gene expression under specific environmental conditions that remain to be defined.