Identification of Linked Legionella pneumophila Genes Essential for Intracellular Growth and Evasion of the Endocytic Pathway
AUTOR(ES)
Andrews, Helene L.
FONTE
American Society for Microbiology
RESUMO
Legionella pneumophila replicates within a specialized phagosome in cultured cells, a function necessary for its pathogenicity. The replicative phagosome lacks membrane marker proteins, such as the glycoprotein LAMP-1, that are indicators of the normal endocytic pathway. We describe the isolation of several Legionella genes essential for intracellular growth and evasion of the endocytic pathway, using a genetic and cell biological approach. We screened 4,960 ethyl methanesulfonate-mutagenized colonies for defects in intracellular growth and trafficking to the replicative phagosome. Six mutant strains of L. pneumophila that had severe intracellular growth defects in mouse bone marrow-derived macrophages were identified. All six mutants were found in phagosomes that colocalized with LAMP-1, indicating defects in intracellular trafficking. The growth defects of two of these strains were complemented by molecular clones from a bank constructed from a wild-type L. pneumophila strain. The inserts from these clones are located in a region of the chromosome contiguous with several other genes essential for intracellular growth. Three mutants could be complemented by single open reading frames placed in trans, one mutant by a gene termed dotH and two additional mutants by a gene termed dotO. A deletion mutation was created in a third gene, dotI, which is located directly upstream of dotH. The ΔdotI strain was also defective for intracellular growth in macrophages, and this defect was complemented by a single open reading frame in trans. Based on sequence analysis and structural predictions, possible roles of dotH, dotI, and dotO in intracellular growth are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=108001Documentos Relacionados
- Identification of Legionella pneumophila genes required for growth within and killing of human macrophages.
- Association of flagellum expression and intracellular growth of Legionella pneumophila.
- Essential Role for the Legionella pneumophila Rep Helicase Homologue in Intracellular Infection of Mammalian Cells
- Macrophage-Induced Genes of Legionella pneumophila: Protection from Reactive Intermediates and Solute Imbalance during Intracellular Growth
- Intracellular growth of Legionella pneumophila within Acanthamoeba castellanii Neff.