Interstrain transfer of the large pathogenicity island (PAPI-1) of Pseudomonas aeruginosa

Proc Natl Acad Sci U S A. 2006 Dec 26;103(52):19830-5. doi: 10.1073/pnas.0606810104. Epub 2006 Dec 18.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Attachment Sites, Microbiological / genetics
  • Chromosomes, Bacterial / genetics
  • Gene Deletion
  • Genomic Islands
  • Multigene Family / genetics
  • Pseudomonas aeruginosa / genetics*
  • Recombination, Genetic / genetics*
  • Transcription, Genetic / genetics