title: Interstrain transfer of the large pathogenicity island (PAPI-1) of Pseudomonas aeruginosa.
abstract: The large Pseudomonas aeruginosa pathogenicity island PAPI-1 of strain PA14 is a cluster of 108 genes that encode a number of virulence features. We demonstrate that, in a subpopulation of cells, PAPI-1 can exist in an extrachromosomal circular form after precise excision from its integration site within the 3' terminus of the tRNA(Lys) gene. Circular PAPI-1 can reintegrate into either of the two tRNA(Lys) genes, including the one that was used for integration of small pathogenicity island PAPI-2 in strain PA14. The excision requires PAPI-1-encoded integrase, a member of the tyrosine recombinase family. PAPI-1 Soj contains the conserved domains of proteins that are related to chromosome and plasmid partition. soj plays a role in maintaining PAPI-1 and mutations in soj result in the loss of PAPI-1 from P. aeruginosa. We further demonstrate that, during coculture, the PAPI-1-containing strains are able to transfer it into P. aeruginosa recipient strains that do not harbor this island naturally. After transfer, PAPI-1 integrates into either of the two tRNA(Lys) genes. PAPI-1 encompasses many features of mobile elements, including mobilization and maintenance modules. Together with the virulence determinants, PAPI-1 plays an important role in the evolution of P. aeruginosa, by expanding its natural habitat from soil and water to animal and human infections.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Qiu
authors.forename: Aditi U
authors.initials: AU
authors.lastname: Gurkar
authors.forename: Stephen
authors.initials: S
authors.lastname: Lory
mesh_terms: D001287:Attachment Sites, Microbiological / Q000235:genetics; D002876:Chromosomes, Bacterial / Q000235:genetics; D017353:Gene Deletion; D044404:Genomic Islands; D005810:Multigene Family / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics