OmpR regulates the two-component system SsrA-ssrB in Salmonella pathogenicity island 2. Journal Article uri icon



  • Salmonella pathogenicity island 2 (SPI-2) encodes a putative, two-component regulatory system, SsrA-SsrB, which regulates a type III secretion system needed for replication inside macrophages and systemic infection in mice. The sensor and regulator homologs, ssrAB (spiR), and genes within the secretion system, including the structural gene ssaH, are transcribed after Salmonella enters host cells. We have studied the transcriptional regulation of ssrAB and the secretion system by using gfp fusions to the ssrA and ssaH promoters. We found that early transcription of ssrA, after entry into macrophages, is most efficient in the presence of OmpR. An ompR mutant strain does not exhibit replication within cultured macrophages. Furthermore, footprint analysis shows that purified OmpR protein binds directly to the ssrA promoter region. We also show that minimal medium, pH 4.5, induces SPI-2 gene expression in wild-type but not ompR mutant strains. We conclude that the type III secretion system of SPI-2 is regulated by OmpR, which activates expression of ssrA soon after Salmonella enters the macrophage.

publication date

  • February 1, 2000

has subject area

Date in CU Experts

  • April 26, 2014 6:04 AM

Full Author List

  • Lee AK; Detweiler CS; Falkow S

author count

  • 3

citation count

  • 124

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9193

Electronic International Standard Serial Number (EISSN)

  • 1098-5530

Additional Document Info

start page

  • 771

end page

  • 781


  • 182


  • 3