Abstract |
L. pneumophila-containing vacuoles (LCVs) exclude endocytic and lysosomal markers in human macrophages and protozoa. We screened a L. pneumophila mini-Tn10 transposon library for mutants, which fail to inhibit the fusion of LCVs with lysosomes by loading of the lysosomal compartment with colloidal iron dextran, mechanical lysis of infected host cells, and magnetic isolation of LCVs that have fused with lysosomes. In silico analysis of the mutated genes, D. discoideum plaque assays and infection assays in protozoa and U937 macrophage-like cells identified well established as well as novel putative L. pneumophila virulence factors. Promising candidates were further analyzed for their co-localization with lysosomes in host cells using fluorescence microscopy. This approach corroborated that the O- methyltransferase, PilY1, TPR-containing protein and polyketide synthase (PKS) of L. pneumophila interfere with lysosomal degradation. Competitive infections in protozoa and macrophages revealed that the identified PKS contributes to the biological fitness of pneumophila strains and may explain their prevalence in the epidemiology of Legionnaires' disease.
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Authors | Olga Shevchuk, Dennis Pägelow, Janine Rasch, Simon Döhrmann, Gabriele Günther, Julia Hoppe, Can Murat Ünal, Marc Bronietzki, Maximiliano Gabriel Gutierrez, Michael Steinert |
Journal | International journal of medical microbiology : IJMM
(Int J Med Microbiol)
Vol. 304
Issue 8
Pg. 1169-81
(Nov 2014)
ISSN: 1618-0607 [Electronic] Germany |
PMID | 25218702
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2014 Elsevier GmbH. All rights reserved. |
Chemical References |
- Bacterial Proteins
- DNA Transposable Elements
- Virulence Factors
- Polyketide Synthases
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Topics |
- Bacterial Proteins
(genetics, metabolism)
- Cell Line
- DNA Transposable Elements
- Dictyostelium
(microbiology)
- Host-Pathogen Interactions
- Humans
- Legionella pneumophila
(genetics, growth & development, physiology)
- Legionnaires' Disease
(microbiology)
- Lysosomes
(metabolism)
- Monocytes
(microbiology)
- Mutagenesis, Insertional
- Polyketide Synthases
(genetics, metabolism)
- Vacuoles
(metabolism, microbiology)
- Virulence Factors
(genetics, metabolism)
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