title: Exploration of the role of the non-coding RNA SbrE in L. monocytogenes stress response.
abstract: 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.
authors.affiliation: Department of Food Science, Cornell University, Ithaca, NY 14853, USA. mw16@cornell.edu.
authors.forename: Sana
authors.initials: S
authors.lastname: Mujahid
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Bergholz
authors.forename: Haley F
authors.initials: HF
authors.lastname: Oliver
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Boor
authors.forename: Martin
authors.initials: M
authors.lastname: Wiedmann
mesh_terms: D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D050296:Microbial Viability / Q000235:genetics; D009876:Operon / Q000235:genetics; D018384:Oxidative Stress / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D012333:RNA, Messenger; D022661:RNA, Untranslated; D012808:Sigma Factor