Identification of the alternative sigma factor regulons of Chlamydia trachomatis using multiplexed CRISPR interference
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ABSTRACT:
ORGANISM(S): Chlamydia trachomatis L2/434/Bu
PROVIDER: GSE230645 | GEO | 2023/09/05
REPOSITORIES: GEO
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Project description:Chlamydia trachomatis is a developmentally regulated, obligate intracellular bacterium that encodes three sigma factors: σ66, σ54, and σ28. σ66 is the major sigma factor controlling most transcription initiation during early- and mid-cycle development as the infectious elementary body (EB) transitions to the non-infectious reticulate body (RB) that replicates within an inclusion inside the cell. The roles of the minor sigma factors, σ54 and σ28, have not been well characterized to date; however, there are data to suggest each functions in late-stage development and secondary differentiation as RBs transition to EBs. As the process of secondary differentiation itself is poorly characterized, clarifying the function of these alternative sigma factors by identifying the genes regulated by them will further our understanding of chlamydial differentiation. We hypothesize that σ54 and σ28 have non-redundant and essential functions for initiating late gene transcription thus mediating secondary differentiation in Chlamydia. Here, we demonstrate the necessity of each minor sigma factor in successfully completing the developmental cycle. We have implemented and validated multiplexed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) interference techniques, novel to the chlamydial field to examine the effects of knocking down each alternative sigma factor individually and simultaneously. In parallel, we also overexpressed each sigma factor. Altering transcript levels for either or both alternative sigma factors resulted in a severe defect in EB production as compared to controls. Furthermore, RNA sequencing identified differentially expressed genes during alternative sigma factor dysregulation, indicating the putative regulons of each. These data demonstrate that the levels of alternative sigma factors must be carefully regulated to facilitate chlamydial growth and differentiation. IMPORTANCE Chlamydia trachomatis is a significant human pathogen in both developed and developing nations. Due to the organism's unique developmental cycle and intracellular niche, basic research has been slow and arduous. However, recent advances in chlamydial genetics have allowed the field to make significant progress in experimentally interrogating the basic physiology of Chlamydia. Broadly speaking, the driving factors of chlamydial development are poorly understood, particularly regarding how the later stages of development are regulated. Here, we employ a novel genetic tool for use in Chlamydia while investigating the effects of dysregulating the two alternative sigma factors in the organism that help control transcription initiation. We provide further evidence for both sigma factors' essential roles in late-stage development and their potential regulons, laying the foundation for deeper experimentation to uncover the molecular pathways involved in chlamydial differentiation.
| S-EPMC10597470 | biostudies-literature
Project description:RNAseq analysis was performed for C. trachomatis serovar L2 and S. pyogenes NZ131 in the presence and absence of tryptophan to monitor transcriptional changes.
2021-11-23 | GSE174036 | GEO
Project description:C. trachomatis possess a cryptic 7.5 kb plasmid of unknown function. Here we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human Chlamydia trachomatis strain L2 (25667R). We found that despite minimal chromosomal polymorphisms the LGV L2 (25667R) strain was indistinguishable from the L2 (434) plasmid positive strain in its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The primary in vitro phenotypic differences between L2 (434) and L2 (25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intra-inclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their ability to colonize and infect the female mouse genital tract. The ID50 of the L2 (25667R) plasmidless strain was 500 fold greater (1.XX x 10X IFU) than the L2 (434) plasmid bearing strain (1. XX x 10X IFU). Transcriptome analysis of the two strains clearly demonstrated a decrease in transcript levels of a subset of chromosomal genes for the L2 (25667R) strain. Among those genes was glgA which encodes for glycogen synthase; a finding consistent with the failure of the L2 (25667R) strain to accumulate glycogen granules. Collectively, these findings support an important role for the plasmid in in vivo infectivity and suggest that this virulence characteristic might be controlled by the plasmids ability to regulate the expression of specific chromosomal genes. These results also support an important role for the plasmid in the pathogenesis of human infection and disease. Keywords: strain comparison C. trachomatis strain L2-25667R compared to strain L2-434
2010-05-06 | E-GEOD-10199 | biostudies-arrayexpress
Project description:Chlamydia trachomatis D serovar was grown in axenic culture with G6P or G6P with glutamine. The data reveal the early transcriptonal regulation in the bacteria.
2020-07-16 | GSE147539 | GEO
Project description:The aim of this study was to perform a microarray analysis of the response pattern of EEC from both large and small bowel to infection in vitro, using Chlamydia trachomatis infection as a model. Two human EEC lines: LCC-18, derived from a neuroendocrine colonic tumour, and CNDT-2, derived from a small intestinal carcinoid, were infected with C. trachomatis serovar LGV II strain 434 (ATCC VR-902B). Penicillin G was used to induce persistent infection. Gene expression levels in infected and persistently infected EEC cells were investigated by microarray analysis
2014-06-03 | E-GEOD-58151 | biostudies-arrayexpress
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.
2011-08-02 | E-GEOD-31149 | biostudies-arrayexpress
Project description:Identification of the alternative sigma factor regulons of Chlamydia trachomatis using multiplexed CRISPR interference
| PRJNA962055 | ENA
Project description:C. trachomatis possess a cryptic 7.5 kb plasmid of unknown function. Here we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human Chlamydia trachomatis strain L2 (25667R). We found that despite minimal chromosomal polymorphisms the LGV L2 (25667R) strain was indistinguishable from the L2 (434) plasmid positive strain in its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The primary in vitro phenotypic differences between L2 (434) and L2 (25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intra-inclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their ability to colonize and infect the female mouse genital tract. The ID50 of the L2 (25667R) plasmidless strain was 500 fold greater (1.XX x 10X IFU) than the L2 (434) plasmid bearing strain (1. XX x 10X IFU). Transcriptome analysis of the two strains clearly demonstrated a decrease in transcript levels of a subset of chromosomal genes for the L2 (25667R) strain. Among those genes was glgA which encodes for glycogen synthase; a finding consistent with the failure of the L2 (25667R) strain to accumulate glycogen granules. Collectively, these findings support an important role for the plasmid in in vivo infectivity and suggest that this virulence characteristic might be controlled by the plasmids ability to regulate the expression of specific chromosomal genes. These results also support an important role for the plasmid in the pathogenesis of human infection and disease. Keywords: strain comparison
2009-01-15 | GSE10199 | GEO
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
2011-08-03 | GSE31149 | GEO
Project description:Chlamydia trachomatis L2/25667R genome sequencing
| PRJEA71105 | ENA