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Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System
09:12

Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System

Published on: March 10, 2020

Legionella pneumophila strain 130b possesses a unique combination of type IV secretion systems and novel Dot/Icm

Gunnar N Schroeder1, Nicola K Petty, Aurélie Mousnier

  • 1Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College, London, United Kingdom.

Journal of Bacteriology
|September 14, 2010
PubMed

Insights

Legionella pneumophila uses a type IV secretion system (T4SS) to infect hosts. This study reveals a core set of T4SS effectors supplemented by variable accessory proteins, explaining strain differences in virulence and prevalence.

Area of Science:

  • Microbiology
  • Genomics
  • Bacterial Pathogenesis

Background:

  • Legionella pneumophila is a waterborne pathogen causing severe pneumonia in humans.
  • Its virulence relies on the Dot/Icm type IV secretion system (T4SS) for effector protein delivery into host cells.

Purpose of the Study:

  • To determine the genome sequence of L. pneumophila strain 130b.
  • To identify conserved and novel Dot/Icm T4SS effectors.
  • To investigate the prevalence of these effectors in clinical and environmental isolates.

Main Methods:

  • Whole-genome sequencing of L. pneumophila strain 130b.
  • Comparative genomic analysis of multiple L. pneumophila strains.
  • Experimental validation of effector translocation.
  • Prevalence analysis using PCR on environmental and clinical isolates.

Main Results:

  • The L. pneumophila 130b genome encodes multiple T4SSs, including Dot/Icm, Trb-1, and Lvh systems.
  • A core set of 107 Dot/Icm T4SS effectors is conserved across sequenced strains.
  • Ten novel Dot/Icm T4SS effectors were identified and validated, with five found in 34-62% of isolates.

Conclusions:

  • L. pneumophila possesses a conserved core of Dot/Icm T4SS effectors.
  • Variable accessory effectors contribute to strain-specific virulence and prevalence.
  • Understanding these effectors is crucial for controlling Legionnaires' disease.

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