title: Chlamydia trachomatis virulence factor CT135 is stable in vivo but highly polymorphic in vitro.
abstract: Chlamydia trachomatis is an important human pathogen causing both ocular and sexually transmitted disease. Recently, we identified CT135 as an important virulence determinant in a mouse infection model. Results from CEL 1 digestion assays and sequencing analyses indicated that CT135 was much more polymorphic in high in vitro passage reference serovars than it was in clinical strains that had undergone limited passaging. Herein, we used targeted next-generation sequencing of the CT134-135 locus, from reference strains and clinical isolates, enabling accurate discovery of single nucleotide polymorphisms and other population genetic variations. Our results indicate that CT134 is stable in all C. trachomatis serovars examined. In contrast, CT135 is highly polymorphic in high-passaged reference ocular and non-LGV genital serovars, with the majority of the mutations resulting in gene disruption. In low-passaged ocular clinical isolates, CT135 was frequently disrupted, whereas in genital clinical isolates CT135 was intact in almost all instances. When a serovar K isolate, with an intact CT134 and CT135, was subjected to serial passage in vitro CT134 remained invariable, while numerous gene interrupting mutations rapidly accumulated in CT135. Collectively, our data indicate that, for genital serovars, CT135 is under strong positive selection in vivo, and negative selection in vitro.
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Bonner
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIH, 903 South 4 Street, Hamilton, MT 59840, USA.
authors.forename: Harlan D
authors.initials: HD
authors.lastname: Caldwell
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIH, 903 South 4 Street, Hamilton, MT 59840, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Carlson
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada.
authors.forename: Morag R
authors.initials: MR
authors.lastname: Graham
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIH, 903 South 4 Street, Hamilton, MT 59840, USA.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Kari
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIH, 903 South 4 Street, Hamilton, MT 59840, USA.
authors.forename: Gail L
authors.initials: GL
authors.lastname: Sturdevant
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada.
authors.forename: Shaun
authors.initials: S
authors.lastname: Tyler
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada.
authors.forename: Adrian
authors.initials: A
authors.lastname: Zetner
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB R3E 3R2, Canada Department of Medical Microbiology, 745 Bannatyne Avenue, Winnipeg, MB R3E 0W9, Canada Grant.McClarty@umanitoba.ca.
authors.forename: Grant
authors.initials: G
authors.lastname: McClarty
mesh_terms: D000818:Animals; D002690:Chlamydia Infections / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D004269:DNA, Bacterial / Q000235:genetics; D017353:Gene Deletion; D014644:Genetic Variation; D042822:Genomic Instability; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D051379:Mice; D009154:Mutation; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors
keywords: CT135; chlamydia trachomatis; deep sequencing; genomics; single nucleotide polymorphism; virulence factor