Expression of Multiple Pili by Legionella pneumophila: Identification and Characterization of a Type IV Pilin Gene and Its Role in Adherence to Mammalian and Protozoan Cells
AUTOR(ES)
Stone, Barbara J.
FONTE
American Society for Microbiology
RESUMO
Legionella pneumophila expresses pili of variable lengths, either long (0.8 to 1.5 μm) or short (0.1 to 0.6 μm), that can be observed by transmission electron microscopy. We have identified a gene in L. pneumophila with homology to the type IV pilin genes (pilEL). An insertion mutation was constructed in pilEL and introduced into the L. pneumophila wild-type strain by allelic exchange. The pilin mutant is defective for expression of long pili. Reintroduction of the pilin locus on a cosmid vector restores expression of the long pili. The L. pneumophila pilEL mutant exhibited approximately a 50% decrease in adherence to human epithelial cells (HeLa and WI-26 cells), macrophages (U937 cells), and Acanthamoeba polyphaga but had a wild-type phenotype for intracellular replication within these cells. Southern hybridization analysis showed that the pilEL locus is present in L. pneumophila serogroups 1 through 13 but is variable in 16 other Legionella species. The presence of a type IV pilin gene and its expression by L. pneumophila may provide an advantage for colonization of lung tissues during Legionnaires’ disease and invasion of amoebas in the environment.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=108119Documentos Relacionados
- Natural Competence for DNA Transformation by Legionella pneumophila and Its Association with Expression of Type IV Pili
- HtrA Homologue of Legionella pneumophila: an Indispensable Element for Intracellular Infection of Mammalian but Not Protozoan Cells
- Acquisition of iron by Legionella pneumophila: role of iron reductase.
- Shuttle mutagenesis of Legionella pneumophila: identification of a gene associated with host cell cytopathicity.
- Role of pili in adherence of Pseudomonas aeruginosa to mammalian buccal epithelial cells.