Analysis of the boundaries of Salmonella pathogenicity island 2 and the corresponding chromosomal region of Escherichia coli K-12

Michael Hensel, Jacqueline E. Shea, Andreas J Baumler, Colin Gleeson, Frederick Blattner, David W. Holden

Research output: Contribution to journalArticle

97 Scopus citations

Abstract

We recently identified a pathogenicity island (SPI2) located at 30.7 centisomes on the Salmonella typhimurium chromosome. SPI2 contains genes encoding a type III secretion system whose function is distinct from that of the type III secretion system encoded by a pathogenicity island (SPI1) at 63 centisomes which is involved in epithelial cell entry. An analysis of the boundaries of SPI2 and comparison with the corresponding region of the Escherichia coli chromosome revealed that SPI2 inserted adjacent to the tRNA(Val) gene. The E. coli chromosome contains 9 kb of DNA at the region corresponding to the SPI2 insertion point which appears to be absent in S. typhimurium. The distribution of SPI1 and SPI2 was examined in various Salmonella isolates. In contrast to type III secretion system genes of SPI1, those of SPI2 are not present in Salmonella bongori, which diverged at the first branch point in the Salmonella lineage. These and other data indicate that SPI2 was acquired by a Salmonella strain already harboring SPI1 by horizontal transfer from an unknown source.

Original languageEnglish (US)
Pages (from-to)1105-1111
Number of pages7
JournalJournal of Bacteriology
Volume179
Issue number4
StatePublished - 1997
Externally publishedYes

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

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