ABSTRACT: Evidence for a post-invasion role of the Chlamydia trachomatis type III secreted effector TmeA in acquisition of host plasma membrane-derived material
Project description:To determine the role that GrgA plays in chlamydial physiology, we constructed a Chlamydia trachomatis mutant that we term L/cgad-peig, in which the chromosomal grgA (ctl0766 or ct504) has been disrupted by Targetron mutagenesis, and the plasmid carries an inducible grgA under the control of anhydrotetracycline (ATC). RNA-Seq analysis was performed for L2/cgad-peig grown with and without ATC.
Project description:Chlamydia trachomatis is an obligate intracellular pathogen that causes trachoma and sextually transmitted disease in human. During early stage of infection, Chlamydia secreted bacterial effector proteins into host cell cytoplasm to help its entry and estabilishment of early replicated niche. We identified a Chlamydia mutant that lack an early Effector. To address the function of this effector, we infected A2EN cells with this mutant (G1V) and its complemented counterpart (G1TEPP) to see what host gene transcriptions are affected by this effector. A2EN cells were mock infected, or infected with a Chlamydia mutant or its complemented counterpart for 4 hour post infection.
Project description:Chlamydia trachomatis is an important human pathogen that replicates inside the infected host cell in a unique vacuole, the inclusion. The formation of this intracellular bacterial niche is essential for productive Chlamydia infections. Despite its importance for Chlamydia biology, a holistic view on the protein composition of the inclusion, including its membrane, is currently missing. Here we describe a newly established method to purify inclusions from C. trachomatis infected epithelial cells and the analysis of the host cell-derived proteome by a combination of label free and stable isotope labeling -based quantitative proteomics. Computational analysis of the proteome data indicated that the inclusion is a complex intracellular trafficking platform that interacts with host cells' antero- and retrograde trafficking pathways. Furthermore, the inclusion is highly enriched for sorting nexins of the SNX-BAR retromer, a complex essential for retrograde trafficking. Functional studies showed that in particular SNX5 controls the C. trachomatis infection and that retrograde trafficking is essential for infectious progeny formation. In summary, our findings suggest that the inclusion of C. trachomatis is well embedded in the hosts' endomembrane system and hijacks retrograde trafficking pathways for effective infection.
Project description:Chlamydia trachomatis is an obligate intracellular pathogen that causes trachoma and sextually transmitted disease in human. During early stage of infection, Chlamydia secreted bacterial effector proteins into host cell cytoplasm to help its entry and estabilishment of early replicated niche. We identified a Chlamydia mutant that lack an early Effector. To address the function of this effector, we infected A2EN cells with this mutant (G1V) and its complemented counterpart (G1TEPP) to see what host gene transcriptions are affected by this effector.
Project description:The obligate intracellular developmental cycle of Chlamydia trachomatis presents significant challenges in defining its proteome. In this study we have applied quantitative proteomics to both the intracellular reticulate body (RB) and the extracellular elementary body (EB) from C. trachomatis. We used C. trachomatis L2 which is a model chlamydial isolate for such a study since it has a high infectivity: particle ratio and there is an excellent quality genome sequence. EBs and RBs (>99% pure) were quantified by chromosomal and plasmid copy number using PCR to determine the concentrations of chlamydial proteins per bacterial cell. RBs harvested at 15h post infection (PI) were purified by three successive rounds of gradient centrifugation. This is the earliest possible time to obtain purified RBs, free from host cell components in quantity, within the constraints of the technology, EBs were purified at 48h PI. We then used two-dimensional reverse phase UPLC to fractionate RB or EB peptides before mass spectroscopic analysis, providing absolute amount estimates of chlamydial proteins.
Project description:In this project we examined the in-vitro effect of female sex hormones (estradiol and progesterone at average physiological concentrations) during a infection mediated by Chlamydia trachomatis serovar D, on the gene expression of human endometrial cell line ECC-1 The effects of the female sex hormones progesterone and oestradiol while infected by Chlamydia trachomatis were examined at two timepoints.
