Mapping and Regulation of Genes within Salmonella Pathogenicity Island 12 That Contribute toIn VivoFitness of Salmonella enterica Serovar Typhimurium Academic Article uri icon

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  • ABSTRACTSalmonellapathogenicity island 12 (SPI-12) ofSalmonella entericaserovar Typhimurium is a 15-kb region that encompasses genesSTM2230toSTM2245and encodes a remnant phage known to contribute to bacterial virulence. In mouse infection experiments and replication assays in macrophages, we demonstrated a role for four genes in SPI-12 for bacterial survival in the host. STM2239, a potential Q antiterminator, showed a prominent contribution to bacterial fitness. Transcriptional reporter experiments, quantitative reverse transcription-PCR (RT-PCR), and immunoblotting demonstrated that the virulence regulator SsrB and STM2239 contribute to transcriptional activation of genes in SPI-12. SsrB was found to indirectly regulate this locus by transcriptional read-through from thesspH2(STM2241) promoter. Chromatin immunoprecipitation showed that STM2239 copurified with the promoter regulatingSTM2237, suggesting that STM2239 may function as an antiterminator to activate adjacent genes. These results demonstrate that bacteriophage genes may be adapted by pathogenic bacteria to improve fitness in the host.


  • Tomljenovic-Berube, Ana M
  • Henriksbo, Brandyn
  • Porwollik, Steffen
  • Cooper, Colin A
  • Tuinema, Brian R
  • McClelland, Michael
  • Coombes, Brian

publication date

  • July 2013

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