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Forward Genetic Approaches in Chlamydia trachomatis
Published on: October 23, 2013
The transcript profile of persistent Chlamydophila (Chlamydia) pneumoniae in vitro depends on the means by which
Andreas Klos1, Jessica Thalmann, Jan Peters
1Department of Medical Microbiology and Hospital Epidemiology, Medizinische Hochschule Hannover, Hannover, Germany.
Abstract:
Expression of specific bacterial genes is differentially regulated during persistent, vs. active, chlamydial infection. Transcript patterns were examined using real-time reverse transcriptase-PCR in four in vitro models of persistence for Chlamydia pneumoniae strain CWL 029, using HeLa cells and normal human monocytes as host. Differential expression of genes encoding cell division proteins was variable when persistence was induced by interferon-gamma, penicillin G, or deferoxamine mesylate treatment, and in the monocyte model of persistence. Expression of genes encoding hsp60s and those specifying sigma-factors also was variable among models. These in vitro observations indicate that chlamydial persistence is not characterizable by a single transcript profile under all circumstances, supporting the idea that persistent infection in vivo is a complex, flexible strategy that promotes long-term survival of these organisms. Each model system studied here can provide information regarding the molecular characteristics of persistent C. pneumoniae infection. However, we do not know which aspect(s) of which model correspond to in vivo disease or other contexts.
Insights
Chlamydia pneumoniae gene expression varies across different models of persistent infection. This suggests that bacterial persistence is a flexible survival strategy, not defined by a single transcript profile.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Chlamydial infections can establish persistent states.
- Gene expression patterns during persistence are not fully understood.
- Understanding chlamydial persistence is crucial for developing effective treatments.
Purpose of the Study:
- To investigate differential gene expression in Chlamydia pneumoniae during in vitro persistence.
- To compare transcript profiles across various models of chlamydial persistence.
- To determine if a single transcript profile characterizes chlamydial persistence.
Main Methods:
- Real-time reverse transcriptase-PCR was used to examine gene expression.
- Four in vitro models of persistence were employed for Chlamydia pneumoniae strain CWL 029.
- Host cells included HeLa cells and normal human monocytes.
Main Results:
- Differential gene expression varied significantly across different persistence models.
- Genes involved in cell division, heat shock proteins (hsp60s), and sigma-factors showed variable expression.
- No single transcript profile consistently characterized chlamydial persistence under tested conditions.
Conclusions:
- Chlamydial persistence is characterized by flexible and context-dependent gene regulation.
- In vitro models provide insights into molecular aspects of persistent C. pneumoniae infection.
- Further research is needed to correlate specific model findings with in vivo disease states.
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