title: Exploration of chlamydial type III secretion system reconstitution in Escherichia coli.
abstract: BACKGROUND
  Type III secretion system is a virulent factor for many pathogens, and is thought to play multiple roles in the development cycle and pathogenesis of chlamydia, an important human pathogen. However, due to the obligate intracellular parasitical nature of chlamydiae and a lack of convenient genetic methodology for the organisms, very limited approaches are available to study the chlamydial type III secretion system. In this study, we explored the reconstitution of a chlamydial type III secretion in Escherichia coli.
  
  
  RESULTS
  We successfully cloned all 6 genomic DNA clusters of the chlamydial type III secretion system into three bacterial plasmids. 5 of the 6 clusters were found to direct mRNA synthesis from their own promoters in Escherichia coli transformed with the three plasmids. Cluster 5 failed to express mRNA using its own promoters. However, fusion of cluster 5 to cluster 6 resulted in the expression of cluster 5 mRNA. Although only two of the type III secretion system proteins were detected transformed E. coli due to limited antibody availability, type III secretion system-like structures were detected in ultrathin sections in a small proportion of transformed E. coli.
  
  
  CONCLUSIONS
  We have successfully generated E. coli expressing all genes of the chlamydial type III secretion system. This serves as a foundation for optimal expression and assembly of the recombinant chlamydial type III secretion system, which may be extremely useful for the characterization of the chlamydial type III secretion system and for studying its role in chlamydial pathogenicity.
authors.affiliation: Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, United States of America.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Bao
authors.forename: Wandy L
authors.initials: WL
authors.lastname: Beatty
authors.forename: Huizhou
authors.initials: H
authors.lastname: Fan
mesh_terms: D058947:Bacterial Secretion Systems / Q000235:genetics*; D002690:Chlamydia Infections / Q000235:genetics; D002692:Chlamydia trachomatis / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D005810:Multigene Family
chemical_list: D058947:Bacterial Secretion Systems