Related Experiment Video
Updated: Jun 15, 2026

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing
Published on: July 6, 2016
Polar localization of the Coxiella burnetii type IVB secretion system
J Kent Morgan1, Brandon E Luedtke, Edward I Shaw
1Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
Abstract:
Coxiella burnetii is a Gram-negative pleomorphic bacterium and the causative agent of Q fever. During infection, the pathogen survives and replicates within a phagosome-like parasitophorous vacuole while influencing cellular functions throughout the host cell, indicating a capacity for effector protein secretion. Analysis of the C. burnetii (RSA 493 strain) genome sequence indicates that C. burnetii contains genes with homology to the Legionella pneumophila Dot/Icm type IVB secretion system (T4BSS). T4BSSs have only been described in L. pneumophila and C. burnetii, marking it a unique virulence determinate. Characterization of bacterial virulence determinants ranging from autotransporter proteins to diverse secretion systems suggests that polar localization may be a virulence mechanism hallmark. To characterize T4BSS subcellular localization in C. burnetii, we analyzed C. burnetii-infected Vero cells by indirect immunofluorescent antibody (IFA) and immunoelectron microscopy (IEM). Using antibodies against the C. burnetii T4BSS homologs IcmT, IcmV, and DotH, IFA show that these proteins are localized to the poles of the bacterium. IEM supports this finding, showing that antibodies against C. burnetii IcmT and DotH preferentially localize to the bacterial cell pole(s). Together, these data demonstrate that the C. burnetii T4BSS localizes to the pole(s) of the bacterium during infection of host cells.
More Related Videos
11:44Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants
Published on: May 13, 2015
09:12Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System
Published on: March 10, 2020
Related Concept Videos
Gram-negative Bacterial Protein Secretion Systems
Bacterial Translocation and Protein Secretion
Formation of Lipopolysaccharides
Regulation of Bacterial Virulence
Bacterial Toxins
Chemotaxis in E. coli