Use of a capture-based pathogen transcript enrichment strategy for RNA-Seq analysis of the Francisella tularensis LVS transcriptome during infection of murine macrophages

PLoS One. 2013 Oct 14;8(10):e77834. doi: 10.1371/journal.pone.0077834. eCollection 2013.

Abstract

Francisella tularensis is a zoonotic intracellular pathogen that is capable of causing potentially fatal human infections. Like all successful bacterial pathogens, F. tularensis rapidly responds to changes in its environment during infection of host cells, and upon encountering different microenvironments within those cells. This ability to appropriately respond to the challenges of infection requires rapid and global shifts in gene expression patterns. In this study, we use a novel pathogen transcript enrichment strategy and whole transcriptome sequencing (RNA-Seq) to perform a detailed characterization of the rapid and global shifts in F. tularensis LVS gene expression during infection of murine macrophages. We performed differential gene expression analysis on all bacterial genes at two key stages of infection: phagosomal escape, and cytosolic replication. By comparing the F. tularensis transcriptome at these two stages of infection to that of the bacteria grown in culture, we were able to identify sets of genes that are differentially expressed over the course of infection. This analysis revealed the temporally dynamic expression of a number of known and putative transcriptional regulators and virulence factors, providing insight into their role during infection. In addition, we identified several F. tularensis genes that are significantly up-regulated during infection but had not been previously identified as virulence factors. These unknown genes may make attractive therapeutic or vaccine targets.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Down-Regulation / genetics
  • Francisella tularensis / genetics*
  • Francisella tularensis / pathogenicity
  • Francisella tularensis / physiology*
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial / genetics
  • Genomic Islands / genetics
  • Humans
  • Macrophages / microbiology*
  • Macrophages / pathology
  • Mice
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sequence Analysis, RNA / methods*
  • Transcription, Genetic
  • Transcriptome / genetics*
  • Tularemia / genetics*
  • Tularemia / microbiology*
  • Up-Regulation / genetics
  • Virulence / genetics
  • Virulence Factors / genetics
  • Virulence Factors / metabolism

Substances

  • RNA, Messenger
  • Virulence Factors

Grants and funding

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.