Expression of Chlamydia trachomatis genes encoding products required for DNA synthesis and cell division during active versus persistent infection

During persistent infection, the intracellular bacterial pathogen Chlamydia trachomatis is viable but severely attenuates the production of new, infectious elementary bodies (EBs). To investigate the reasons for this lack of new EB output, we analysed the expression of chlamydial genes encoding prod...

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Bibliographic Details
Published in:Molecular microbiology 2001-08, Vol.41 (3), p.731-741
Main Authors: Gérard, Hervé C., Krauße‐Opatz, Birgit, Wang, Zhao, Rudy, Debbie, Rao, J. Papa, Zeidler, Henning, Schumacher, H. Ralph, Whittum‐Hudson, Judith A., Köhler, Lars, Hudson, Alan P.
Format: Article
Language:English
Subjects:
Bacterial Proteins - genetics
Bacterial Proteins - metabolism
Cell Division - genetics
Chlamydia trachomatis
Chlamydia trachomatis - cytology
Chlamydia trachomatis - genetics
Chlamydia trachomatis - growth & development
Chlamydia trachomatis - metabolism
Chromosomes, Bacterial - genetics
DNA Primers
DNA Replication - genetics
ftsK gene
ftsW gene
Gene Expression Regulation, Bacterial
Gene Expression Regulation, Developmental
Genes, Bacterial - genetics
Humans
Models, Biological
Monocytes - microbiology
mutS gene
parB gene
Reverse Transcriptase Polymerase Chain Reaction
RNA, Bacterial - analysis
RNA, Bacterial - genetics
Synovial Fluid - microbiology
Transcription, Genetic
Tumor Cells, Cultured
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Summary:During persistent infection, the intracellular bacterial pathogen Chlamydia trachomatis is viable but severely attenuates the production of new, infectious elementary bodies (EBs). To investigate the reasons for this lack of new EB output, we analysed the expression of chlamydial genes encoding products required for DNA replication and cell division, using in vitro models of active versus persistent infection and synovial tissue samples from patients with chronic Chlamydia‐associated arthritis. Hep‐2 cells were infected with K serovar C. trachomatis and harvested at t = 0–48 h post‐infection (p.i.; active). Human monocytes were infected similarly and harvested at t = 1–7 days p.i. (persistent). RNA preparations from infected/uninfected cells and patient samples were subjected to reverse transcription–polymerase chain reaction (RT–PCR) targeting polA, dnaA, mutS and parB mRNA, related to chlamydial DNA replication/segregation; these were expressed in infected Hep‐2 cells from 11 to 48 h p.i.; ftsK and ftsW, related to cell division, were expressed similarly. Real‐time PCR analyses demonstrated that significant accumulation of chlamydial chromosome began at about 12 h p.i. in infected Hep‐2 cells. In infected human monocytes, polA, dnaA, mutS and parB mRNA were produced from days 1–7 p.i. and were weakly expressed in patient samples. Real‐time PCR indicated the continuing accumulation of chlamydial chromosome during the 7 day monocyte infection, although the rate of such accumulation was lower than that occurring during active growth. However, transcripts from ftsK and ftsW were detected only at 1 day p.i. in infected monocytes but not thereafter, and they were absent in all patient samples. Thus, genes whose products are required for chlamydial DNA replication are expressed during persistence, but transcription of genes whose products are required for cytokinesis is severely downregulated. These data explain, at least in part, the observed attenuation of new EB production during chlamydial persistence.
ISSN:0950-382X
1365-2958
DOI:10.1046/j.1365-2958.2001.02550.x