title: Genome-based identification of chromosomal regions specific for Salmonella spp.
abstract: Acquisition of genomic elements by horizontal gene transfer represents an important mechanism in the evolution of bacterial species. Pathogenicity islands are a subset of horizontally acquired elements present in various pathogens. These elements are frequently located adjacent to tRNA genes. We performed a comparative genome analysis of Salmonella enterica serovars Typhi and Typhimurium and Escherichia coli and scanned tRNA loci for the presence of species-specific, horizontally acquired genomic elements. A large number of species-specific elements were identified. Here, we describe the characteristics of four large chromosomal insertions at tRNA genes of Salmonella spp. The tRNA-associated elements harbor various genes previously identified as single virulence genes, indicating that these genes have been acquired with large chromosomal insertions. Southern blot analyses confirmed that the tRNA-associated elements are specific to Salmonella and also indicated a heterogeneous distribution within the salmonellae. Systematic scanning for insertions at tRNA genes thus represents a tool for the identification of novel pathogenicity islands.
authors.affiliation: Institut für Klinische Mikrobiologie, Immunologie und Hygiene, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Imke
authors.initials: I
authors.lastname: Hansen-Wester
authors.forename: Michael
authors.initials: M
authors.lastname: Hensel
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D016680:Genome, Bacterial; D051379:Mice; D008810:Mice, Inbred C57BL; D010802:Phylogeny; D012343:RNA, Transfer / Q000235:genetics*; D012475:Salmonella / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012343:RNA, Transfer