title: A Chlamydia trachomatis strain with a chemically generated amino acid substitution (P370L) in the cthtrA gene shows reduced elementary body production.
abstract: BACKGROUND
  Chlamydia (C.) trachomatis is the most prevalent bacterial sexually transmitted infection worldwide and the leading cause of preventable blindness. Genetic approaches to investigate C. trachomatis have been only recently developed due to the organism's intracellular developmental cycle. HtrA is a critical stress response serine protease and chaperone for many bacteria and in C. trachomatis has been previously shown to be important for heat stress and the replicative phase of development using a chemical inhibitor of the CtHtrA activity. In this study, chemically-induced SNVs in the cthtrA gene that resulted in amino acid substitutions (A240V, G475E, and P370L) were identified and characterized.
  
  
  METHODS
  SNVs were initially biochemically characterized in vitro using recombinant protein techniques to confirm a functional impact on proteolysis. The C. trachomatis strains containing the SNVs with marked reductions in proteolysis were investigated in cell culture to identify phenotypes that could be linked to CtHtrA function.
  
  
  RESULTS
  The strain harboring the SNV with the most marked impact on proteolysis (cthtrA P370L) was detected to have a significant reduction in the production of infectious elementary bodies.
  
  
  CONCLUSIONS
  This provides genetic evidence that CtHtrA is critical for the C. trachomatis developmental cycle.
authors.affiliation: Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD, 4059, Australia. james.marsh@qut.edu.au.
authors.forename: James W
authors.initials: JW
authors.lastname: Marsh
authors.affiliation: Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD, 4059, Australia. bryan.wee@qut.edu.au.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Wee
authors.affiliation: National School of Pharmacy, University of Otago, PO Box 56, Dunedin, 9054, New Zealand. joel.tyndall@otago.ac.nz.
authors.forename: Joel D A
authors.initials: JD
authors.lastname: Tyndall
authors.affiliation: Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD, 4059, Australia. b.lott@qut.edu.au.
authors.forename: William B
authors.initials: WB
authors.lastname: Lott
authors.affiliation: Department of Molecular Genetics and Microbiology, Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC, 27710, USA. robert.bastidas@duke.edu.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bastidas
authors.affiliation: Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA. hcaldwell@niaid.nih.gov.
authors.forename: Harlan D
authors.initials: HD
authors.lastname: Caldwell
authors.affiliation: Department of Molecular Genetics and Microbiology, Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC, 27710, USA. raphael.valdivia@duke.edu.
authors.forename: Raphael H
authors.initials: RH
authors.lastname: Valdivia
authors.affiliation: Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA. karil@niaid.nih.gov.
authors.forename: L
authors.initials: L
authors.lastname: Kari
authors.affiliation: Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD, 4059, Australia. w.huston@qut.edu.au.
authors.forename: Wilhelmina M
authors.initials: WM
authors.lastname: Huston
mesh_terms: D019943:Amino Acid Substitution; D002460:Cell Line; D002692:Chlamydia trachomatis / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D006801:Humans; D002479:Inclusion Bodies / Q000382:microbiology*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D057057:Serine Proteases / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D018832:Molecular Chaperones; D050505:Mutant Proteins; D037521:Virulence Factors; D057057:Serine Proteases