A GrgA-Euo-HrcA transcriptional regulatory network controls the growth and development of the obligate intracellular bacterium Chlamydia
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ABSTRACT:
ORGANISM(S): Chlamydia trachomatis
PROVIDER: GSE153747 | GEO | 2021/07/08
REPOSITORIES: GEO
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Project description:Both prokaryotic and eukaryotic organisms take deterministic decisions to reprogram cell fates. A macroscopic manifestation of such an event is the remodelling of the cellsâ morphology and it typically is governed at the molecular scale by massive reorganization of the cellular transcriptome. With the regulation at the level of transcription initiation representing the most common form for such developmental reprogramming, cells typically rely on one or several master regulators to coordinate the the activity of hundreds of genes simultaneously by directly binding to their promoters. Despite the apparent simplicity of prokaryotes and their reduced genome size compared to that of their eukaryotic counterparts, free-living bacteria typically encode hundreds of transcription factors (TFs) in their genomes that could act as master TFs. By contrast, obligate intracellular bacteria such as Chlamydiae have a drastically reduced genome due to their intimate association with the host and thus a smaller number of TF genes. The genomes of members of the Chlamydiaceae family, which include the well-known bacterial pathogens Chlamydia trachomatis and Chlamydia pneumoniae, are only 1-1.2 Mbp. By contrast, members of the environmental Chlamydiae Waddlia chondrophila and Parachlamydia acanthamoebae have a 2-fold and 3-fold larger genome, respectively, likely allowing for an expansion of the host range while still retaining their host dependence and parasitic life style. Moreover, they all exhibit a characteristic chlamydial developmental cycle via two functionally specialized morphotypes, the infectious non-dividing elementary bodies (EBs) and the non-infectious dividing reticulate bodies (RBs). This developmental cycle is usually divided in three stages: the early stage during which EBs enter host cells and differentiate into RBs; the mid-stage where RBs proliferate inside a vacuole called inclusion and the late stage where RBs differentiate back into EBs and are released after exocytosis or cell lysis. Chlamydial genes are thus classified into three different temporal classes (early, mid and late expressed genes), likely reflecting the need of these transcripts in each of the three developmental stages. W. chondrophila, an emerging pathogen implicated in abortion in bovine and miscarriage in humans, encodes less than 20 TFs, 10 of which are conserved among the Chlamydiae. In light of this low TF multiplicity in the chlamydial pan-genome along with the common developmental cycle and parasitic life style, we aimed to define the regulatory pan-genome of each these conserved TFs to identify the elusive chlamydial master regulator and to characterize underling specificity for its target promoters using chromatin-immunoprecipitation followed by deep-sequencing (ChIP-Seq) of chlamydial cells growing inside the host. The immunochemistry of ChIP-Seq has the advantage of minimizing the contaminating nucleic acids compared to chlamydial transcriptome studies, it has the added benefit of providing the first unambiguous glimpse into the regulatory landscape of a bacterium inside host, offering a solid framework in understanding the stochastic and/or deterministic switches that bacteria rely on during infections. Examination of the regulatory network of an intracellular pathogen
2016-02-19 | E-GEOD-68059 | biostudies-arrayexpress
Project description:In this project we examined in-vitro effect of female sex hormones, estradiol and progesterone at average physiological concentration level on Chlamydia trachomatis gene expression level. Regulation of chlamydial gene expression by the female sex hormones oestradiol and progesterone was examined. A total of 16 chlamydial arrays were analysed with the 4 culture conditions (no hormone, E, P, E+P) x four replicates. Bacterial samples were grown in non-hormone treated culture were used as control
2010-09-16 | E-GEOD-24119 | biostudies-arrayexpress
Project description:A GrgA-Euo-HrcA transcriptional regulatory network controls the growth and development of the obligate intracellular bacterium Chlamydia
| PRJNA643854 | ENA
Project description:The pathogenic bacterium Chlamydia reproduces via an unusual intracellular developmental cycle in which it converts from a dividing form (reticulate body or RB) to an infectious form (elementary body or EB). The transcription factor Euo has been proposed as a developmental regulator in C. trachomatis because it repressed a number of late chlamydial promoters, which are transcribed during RB-to-EB conversion. To define the Euo regulon, we performed a genome-wide study that combined Euo DNA Immunoprecipitation-seq (DIP-seq) studies with RNA-seq analysis of HeLa cells infected with an Euo-overexpressing C. trachomatis strain. We demonstrate that Euo directly regulates ~7% of C. trachomatis genes. However, only about half were downregulated (28/61; 45.9%) by Euo overexpression while paradoxically the other half were upregulated (33/61; 54.1%). Intriguingly, all downregulated genes were late genes, while the majority of upregulated genes were midcycle genes, which are transcribed during RB replication. DIP analysis showed that Euo occupancy sites were restricted to the core promoter region for downregulated genes, but were located over a wider region immediately upstream of the promoter for upregulated genes. We also found that Euo controls its own expression through a negative feedback mechanism. Electron microscopy analysis of cells infected with the Euo-overexpressing strain showed fewer EBs, consistent with a block in RB-to-EB conversion, as well as fewer and larger RBs. Together, these findings broaden the role of Euo as a developmental regulator that functions as both a transcriptional repressor of late genes and a transcriptional activator of midcycle genes in C. trachomatis.
2023-05-03 | GSE202415 | GEO
Project description:The pathogenic bacterium Chlamydia reproduces via an unusual intracellular developmental cycle in which it converts from a dividing form (reticulate body or RB) to an infectious form (elementary body or EB). The transcription factor Euo has been proposed as a developmental regulator in C. trachomatis because it repressed a number of late chlamydial promoters, which are transcribed during RB-to-EB conversion. To define the Euo regulon, we performed a genome-wide study that combined Euo DNA Immunoprecipitation-seq (DIP-seq) studies with RNA-seq analysis of HeLa cells infected with an Euo-overexpressing C. trachomatis strain. We demonstrate that Euo directly regulates ~7% of C. trachomatis genes. However, only about half were downregulated (28/61; 45.9%) by Euo overexpression while paradoxically the other half were upregulated (33/61; 54.1%). Intriguingly, all downregulated genes were late genes, while the majority of upregulated genes were midcycle genes, which are transcribed during RB replication. DIP analysis showed that Euo occupancy sites were restricted to the core promoter region for downregulated genes, but were located over a wider region immediately upstream of the promoter for upregulated genes. We also found that Euo controls its own expression through a negative feedback mechanism. Electron microscopy analysis of cells infected with the Euo-overexpressing strain showed fewer EBs, consistent with a block in RB-to-EB conversion, as well as fewer and larger RBs. Together, these findings broaden the role of Euo as a developmental regulator that functions as both a transcriptional repressor of late genes and a transcriptional activator of midcycle genes in C. trachomatis.
2024-05-03 | GSE202414 | GEO
Project description:The pathogenic bacterium Chlamydia reproduces via an unusual intracellular developmental cycle in which it converts from a dividing form (reticulate body or RB) to an infectious form (elementary body or EB). The transcription factor Euo has been proposed as a developmental regulator in C. trachomatis because it repressed a number of late chlamydial promoters, which are transcribed during RB-to-EB conversion. To define the Euo regulon, we performed a genome-wide study that combined Euo DNA Immunoprecipitation-seq (DIP-seq) studies with RNA-seq analysis of HeLa cells infected with an Euo-overexpressing C. trachomatis strain. We demonstrate that Euo directly regulates ~7% of C. trachomatis genes. However, only about half were downregulated (28/61; 45.9%) by Euo overexpression while paradoxically the other half were upregulated (33/61; 54.1%). Intriguingly, all downregulated genes were late genes, while the majority of upregulated genes were midcycle genes, which are transcribed during RB replication. DIP analysis showed that Euo occupancy sites were restricted to the core promoter region for downregulated genes, but were located over a wider region immediately upstream of the promoter for upregulated genes. We also found that Euo controls its own expression through a negative feedback mechanism. Electron microscopy analysis of cells infected with the Euo-overexpressing strain showed fewer EBs, consistent with a block in RB-to-EB conversion, as well as fewer and larger RBs. Together, these findings broaden the role of Euo as a developmental regulator that functions as both a transcriptional repressor of late genes and a transcriptional activator of midcycle genes in C. trachomatis.
2023-06-21 | GSE202416 | GEO
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.
2023-11-29 | GSE234589 | GEO
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.
2016-06-28 | PXD003025 | Pride
Project description:Chlamydia trachomatis causes chronic inflammatory diseases of the eye and genital tract of global medical importance. The chlamydial plasmid plays an important role in the pathophysiology of these diseases as plasmid-deficient organisms are highly attenuated. The plasmid encodes both noncoding RNAs and eight conserved ORFs of undefined function. To understand plasmid gene function we generated plasmid shuttle vectors with deletions in each of the eight ORFs. The individual deletion mutants were used to transform chlamydiae and the transformants were characterized in terms of plasmid biology and transcriptional profiling. We show that pgp1-2, -6 and -8 are essential for plasmid maintenance while the other ORFs can be deleted and the plasmid stably maintained. We further show that a pgp4 knockout mutant exhibits an in vitro phenotype similar to its isogenic plasmid-less strain in terms of abnormal inclusion morphology and lack of glycogen accumulation. Microarray and qRT-PCR analysis revealed that pgp4 is involved in transcriptional regulation of multiple chromosomal genes; including the glycogen synthase gene glgA. Based on our results, we propose that Pgp1 is a plasmid replicative helicase, Pgp2 is a plasmid replication protein, Pgp4 is a transcriptional regulator of virulence associated chromosomal genes, and Pgp6-8 are plasmid partitioning proteins. These findings have important implications for understanding the plasmidM-bM-^@M-^Ys role in chlamydial pathogenesis and the development of novel antigenically multivalent live-attenuated chlamydial vaccines. Chlamydia trachomatis wild type vs. two deletion mutants, and mock
2013-02-28 | E-GEOD-40979 | biostudies-arrayexpress
Project description:The obligate intracellular bacterium Chlamydia trachomatis replicates in a cytosolic vacuole in human epithelial cells. Infection of human cells with C. trachomatis causes substantial changes to many host cell signalling pathways but the molecular basis of such influence is not well understood. Studies of gene transcription of the infected cell have shown altered transcription of many host cell genes, indicating a transcriptional response of the host cell to the infection. We here describe that infection of human cells with C. trachomatis as well as infection of murine cells with C. muridarum profoundly inhibits protein synthesis of the infected host cell. This inhibition was accompanied by changes to the ribosomal profile of the infected cell indicative of a block of translation initiation, most likely as part of a stress response. The chlamydial protease CPAF also reduced protein synthesis in uninfected cells although CPAF-deficient C. trachomatis showed no defect in this respect. Analysis of polysomal mRNA as a proxy of actively transcribed mRNA identified a number of biological processes differentially affected by chlamydial infection. Mapping of differentially regulated genes onto a protein interaction network identified nodes of up- and down-regulated networks during chlamydial infection. Proteomic analysis of protein synthesis further suggested translational regulation of host cell functions by chlamydial infection. These results demonstrate reprogramming of the host cell during chlamydial infection through the alteration of protein synthesis.
2019-05-21 | GSE114556 | GEO