Display Settings:

Format

Send to:

Choose Destination
Infect Immun. 2013 Mar;81(3):636-44. doi: 10.1128/IAI.01305-12. Epub 2013 Jan 14.

Chlamydia trachomatis plasmid-encoded Pgp4 is a transcriptional regulator of virulence-associated genes.

Author information

  • 1Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.

Abstract

Chlamydia trachomatis causes chronic inflammatory diseases of the eye and genital tract and has global medical importance. The chlamydial plasmid plays an important role in the pathophysiology of these diseases, as plasmid-deficient organisms are highly attenuated. The cryptic plasmid carries noncoding RNAs and eight conserved open reading frames (ORFs). To understand plasmid gene function, we generated plasmid shuttle vectors with deletions in each of the eight ORFs. The individual deletion mutants were used to transform chlamydiae and the transformants were characterized phenotypically and at the transcriptional level. We show that pgp1, -2, -6, and -8 are essential for plasmid maintenance, while the other ORFs can be deleted and the plasmid stably maintained. We further show that a pgp4 knockout mutant exhibits an in vitro phenotype similar to its isogenic plasmidless strain, in terms of abnormal inclusion morphology and lack of glycogen accumulation. Microarray and qRT-PCR analysis revealed that Pgp4 is a transcriptional regulator of plasmid-encoded pgp3 and multiple chromosomal genes, including the glycogen synthase gene glgA, that are likely important in chlamydial virulence. Our findings have major implications for understanding the plasmid's role in chlamydial pathogenesis at the molecular level.

Comment in

PMID:
23319558
[PubMed - indexed for MEDLINE]
PMCID:
PMC3584862
Free PMC Article

Images from this publication.See all images (4)Free text

Fig 1
Fig 2
Fig 3
Fig 4
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk