Transcription factor σB plays an important role in the production of extracellular membrane-derived vesicles in Listeria monocytogenes

PLoS One. 2013 Aug 20;8(8):e73196. doi: 10.1371/journal.pone.0073196. eCollection 2013.

Abstract

Gram-negative bacteria produce extracellular outer membrane vesicles (OMVs) that interact with host cells. Unlike Gram-negative bacteria, less is known about the production and role of extracellular membrane vesicles (MVs) in Gram-positive bacteria. The food-borne pathogen Listeria monocytogenes can survive under extreme environmental and energy stress conditions and the transcription factor σ(B) is involved in this survival ability. Here, we first determined the production of MVs from L. monocytogenes and evaluated whether general stress transcription factor σ(B) affected production of MVs in L. monocytogenes. L. monocytogenes secreted MVs during in vitro broth culture. The wild-type strain actively produced MVs approximately nine times more and also produced more intact shapes of MVs than those of the isogenic ΔsigB mutant. A proteomic analysis showed that 130 and 89 MV proteins were identified in the wild-type and ΔsigB mutant strains, respectively. Wild-type strain-derived MVs contained proteins regulated by σ(B) such as transporters (OpuCA and OpuCC), stress response (Kat), metabolism (LacD), translation (InfC), and cell division protein (FtsZ). Gene Ontology (GO) enrichment analysis showed that wild-type-derived MV proteins corresponded to several GO terms, including response to stress (heat, acid, and bile resistance) and extracellular polysaccharide biosynthetic process, but not the ΔsigB mutant. Internalin B (InlB) was almost three times more contained in MVs derived from the wild-type strain than in MVs derived from the ΔsigB mutant. Taken together, these results suggest that σ(B) plays a pivotal role in the production of MVs and protein profiles contained in MVs. L. monocytogenes MVs may contribute to host infection and survival ability under various stressful conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / classification
  • Bacterial Proteins / metabolism
  • Blotting, Western
  • Chromatography, Liquid
  • Extracellular Space / metabolism*
  • Gene Ontology
  • Listeria monocytogenes / metabolism*
  • Listeria monocytogenes / pathogenicity
  • Listeria monocytogenes / ultrastructure
  • Mutation
  • Secretory Vesicles / metabolism*
  • Secretory Vesicles / ultrastructure
  • Sigma Factor / metabolism*
  • Spectrometry, Mass, Electrospray Ionization
  • Virulence Factors / metabolism

Substances

  • Bacterial Proteins
  • SigB protein, Listeria monocytogenes
  • Sigma Factor
  • Virulence Factors

Grants and funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (grant no. 2012R1A1A3008038 to J.H.S) and the Korea Basic Science Institute (T33414). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.