title: Assessment of the load and transcriptional dynamics of Chlamydia trachomatis plasmid according to strains' tissue tropism.
abstract: Chlamydia trachomatis maintain a conserved plasmid, which is a primary regulator of chromosomal genes, but there is no experimental evidences associating it with the strains' differential tissue tropism (ocular and genital mucosae, and lymph nodes). We investigated if the number of plasmids per strain correlate with expression profiles of plasmid ORFs and small anti-sense RNAs (sRNAs), and also if these molecular features underlie tropism dissimilarities. We performed absolute and relative qPCR to determine both the plasmid load and expression throughout C. trachomatis development. Our findings suggest that plasmid load (never exceeding 8 copies) is not a function of expression needs and does not reflect tissue tropism. However, for most ORFs, ocular strains presented lower expression than genital or lymphogranuloma venereum (LGV) strains, and ORF6/pgp4 (transcriptional regulator of virulence associated genes) presented the highest mean expression among strains, followed by the virulence factor ORF5/pgp3 (also regulated by ORF6/pgp4). More, the mean expression levels of the sRNA-2 (anti-sense to ORF2/pgp8) were up to 100-fold higher than those of the ORFs, and up to 12-fold higher than that of sRNA-7 (anti-sense to ORF7/pgp5) for the LGV strains. Overall, besides the known regulatory role of C. trachomatis plasmid, its transcriptional dynamics sustains tropism differences.
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Ferreira
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
authors.forename: Vítor
authors.initials: V
authors.lastname: Borges
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Nunes
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Borrego
authors.affiliation: Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal. Electronic address: j.paulo.gomes@insa.min-saude.pt.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Gomes
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000235:genetics* / Q000502:physiology; D015817:Eye Infections / Q000382:microbiology; D018628:Gene Dosage; D006801:Humans; D009928:Organ Specificity; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D060737:Reproductive Tract Infections / Q000382:microbiology; D013045:Species Specificity; D014158:Transcription, Genetic; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors