Transcriptome analysis of oocyst, tachyzoite, and bradyzoite development in the type II Toxoplasma gondii strain M4.
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ABSTRACT:
ORGANISM(S): Toxoplasma gondii
PROVIDER: GSE32427 | GEO | 2011/10/01
SECONDARY ACCESSION(S): PRJNA147883
REPOSITORIES: GEO
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Project description:There were three primary objectives to the overall experiment. I. Describe the transcriptome of the oocyst through its development beginning with the freshly excreted, unsporulated oocyst at “Day 0” to a fully sporulated and mature oocyst at “Day 10” and including a mid-sporulation timepoint at “Day 4”. II. Compare the transcriptomes of in vitro vs. in vivo derived bradyzoites. III. Compare expression data from three life stages (oocyst, bradyzoite and tachyzoite) from the same parasite isolate, M4, which has been been characterized as a Type II strain. Each array represents seperately isolated and processed RNA samples. (Two samples per time point/developmental stage) RNA samples were obtained from: 1. Oocysts harvested from kitten feces and purified for RNA extraction at Day 0, (not sporulated), Day 4 post-induction of sporulation (mid-sporulation) and Day 10 post-induction of sporulation (fully sporulated). Oocysts were collected and combined from two kittens that were infected with the same starting material (mouse brains containing bradyzoite cysts of the same parasite strain). Duplicate samples were obtained from feces collected and purified on separate days. 2. Bradyzoite cysts harvested from the brains of mice that were infected with oocysts from the same strain (obtained from the oocysts harvested from kittens as described for the oocyst RNA). Mice were treated with 0.44 µg/ml sulfadiazine in their water days 11-21 pi. Mice were sacrificed on day 21 for cyst purification. 3. In vitro 4 and 8 dpi bradyzoite and 2 dpi tachyzoite samples are from separately infected cultures of human foreskin fibroblasts (HFFs) (replicates were infected on the same day). The parasites used for the initial infections were derived from the same culture. Samples were harvested independently and kept separate for all the subsequent processing and labeling steps.
2011-09-30 | E-GEOD-32427 | biostudies-arrayexpress
Project description:Asexual development in Toxoplasma gondii is a vital aspect of the parasite's life cycle, allowing transmission and avoidance of the host immune response. Differentiation of rapidly dividing tachyzoites into slowly growing, encysted bradyzoites involves significant changes in both physiology and morphology. We generated microarrays of 4,400 Toxoplasma cDNAs, representing a minimum of 600 genes (based on partial sequencing), and used these microarrays to study changes in transcript levels during tachyzoite-to-bradyzoite differentiation. This approach has allowed us to (i) determine expression profiles of previously described developmentally regulated genes, (ii) identify novel developmentally regulated genes, and (iii) identify distinct classes of genes based on the timing and magnitude of changes in transcript levels. Whereas microarray analysis typically involves comparisons of mRNA levels at different time points, we have developed a method to measure relative transcript abundance between genes at a given time point. This method was used to determine transcript levels in parasites prior to differentiation and to further classify bradyzoite-induced genes, thus allowing a more comprehensive view of changes in gene expression than is provided by standard expression profiles. Newly identified developmentally regulated genes include putative surface proteins (a SAG1-related protein, SRS9, and a mucin-domain containing protein), regulatory and metabolic enzymes (methionine aminopeptidase, oligopeptidase, aminotransferase, and glucose- 6-phosphate dehydrogenase homologues), and a subset of genes encoding secretory organelle proteins (MIC1, ROP1, ROP2, ROP4, GRA1, GRA5, and GRA8). This analysis permits the first in depth look at changes in gene expression during development of this complex protozoan parasite. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-13 | GSE3120 | GEO
Project description:Asexual development in Toxoplasma gondii is a vital aspect of the parasite's life cycle, allowing transmission and avoidance of the host immune response. Differentiation of rapidly dividing tachyzoites into slowly growing, encysted bradyzoites involves significant changes in both physiology and morphology. We generated microarrays of 4,400 Toxoplasma cDNAs, representing a minimum of 600 genes (based on partial sequencing), and used these microarrays to study changes in transcript levels during tachyzoite-to-bradyzoite differentiation. This approach has allowed us to (i) determine expression profiles of previously described developmentally regulated genes, (ii) identify novel developmentally regulated genes, and (iii) identify distinct classes of genes based on the timing and magnitude of changes in transcript levels. Whereas microarray analysis typically involves comparisons of mRNA levels at different time points, we have developed a method to measure relative transcript abundance between genes at a given time point. This method was used to determine transcript levels in parasites prior to differentiation and to further classify bradyzoite-induced genes, thus allowing a more comprehensive view of changes in gene expression than is provided by standard expression profiles. Newly identified developmentally regulated genes include putative surface proteins (a SAG1-related protein, SRS9, and a mucin-domain containing protein), regulatory and metabolic enzymes (methionine aminopeptidase, oligopeptidase, aminotransferase, and glucose- 6-phosphate dehydrogenase homologues), and a subset of genes encoding secretory organelle proteins (MIC1, ROP1, ROP2, ROP4, GRA1, GRA5, and GRA8). This analysis permits the first in depth look at changes in gene expression during development of this complex protozoan parasite. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. User Defined
2005-08-13 | E-GEOD-3120 | biostudies-arrayexpress
Project description:Developmental switching in Toxoplasma gondii, from the virulent tachyzoite to the relatively quiescent bradyzoite stage, is responsible for disease propagation and reactivation. We have generated tachyzoite to bradyzoite differentiation (Tbd-) mutants in T. gondii and used these in combination with a cDNA microarray to identify developmental pathways in bradyzoite formation. Four independently generated Tbd- mutants were analysed and had defects in bradyzoite development in response to multiple bradyzoite-inducing conditions, a stable phenotype after in vivo passages and a markedly reduced brain cyst burden in a murine model of chronic infection. Transcriptional profiles of mutant and wild-type parasites, growing under bradyzoite conditions, revealed a hierarchy of developmentally regulated genes, including many bradyzoite-induced genes whose transcripts were reduced in all mutants. A set of non-developmentally regulated genes whose transcripts were less abundant in Tbd- mutants were also identified. These may represent genes that mediate downstream effects and/or whose expression is dependent on the same transcription factors as the bradyzoite-induced set. Using these data, we have generated a model of transcription regulation during bradyzoite development in T. gondii. Our approach shows the utility of this system as a model to study developmental biology in single-celled eukaryotes including protozoa and fungi. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-13 | GSE3117 | GEO
Project description:Developmental switching in Toxoplasma gondii, from the virulent tachyzoite to the relatively quiescent bradyzoite stage, is responsible for disease propagation and reactivation. We have generated tachyzoite to bradyzoite differentiation (Tbd-) mutants in T. gondii and used these in combination with a cDNA microarray to identify developmental pathways in bradyzoite formation. Four independently generated Tbd- mutants were analysed and had defects in bradyzoite development in response to multiple bradyzoite-inducing conditions, a stable phenotype after in vivo passages and a markedly reduced brain cyst burden in a murine model of chronic infection. Transcriptional profiles of mutant and wild-type parasites, growing under bradyzoite conditions, revealed a hierarchy of developmentally regulated genes, including many bradyzoite-induced genes whose transcripts were reduced in all mutants. A set of non-developmentally regulated genes whose transcripts were less abundant in Tbd- mutants were also identified. These may represent genes that mediate downstream effects and/or whose expression is dependent on the same transcription factors as the bradyzoite-induced set. Using these data, we have generated a model of transcription regulation during bradyzoite development in T. gondii. Our approach shows the utility of this system as a model to study developmental biology in single-celled eukaryotes including protozoa and fungi. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. User Defined
2005-08-13 | E-GEOD-3117 | biostudies-arrayexpress
Project description:The purpose of this data set is to determine if bradyzoites impact the host transcripton in a similar manner as tachyzoites. We found that 3853 differentially expressed genes (DEGs) are shared between tachyzoite infected cells and bradyzoite infected cells (41%; 2161 up-reg., 1692 down-reg.) when compared to uninfected host samples, leaving 3356 tachyzoite specific DEGs (1488 up-reg., 1868 down-reg.), and 1951 DEGs specific to bradyzoite infection (1075 up-reg., 876 down-reg). We conclude therefore that bradyzoites manipulate the host cell and that this is unique when compared to tachyzoites.
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Project description:Parasites grown as either tachyzoites or bradyzoites for 40 hours were pulsed with 2,4-dithiouracil (DTU) for 1 hour. Following the pulse, mRNA was extracted and either used directly in microarray experiments (Abundance Arrays) or biotinylated and purified to select DTU labeled RNAs that were then used in microarray experiments (Synthesis Arrays). Two independent tachyzoite and bradyzoite preparations were made and duplicate microarrays were performed for each sample. A development or differentiation experiment design type assays events associated with development or differentiation or moving through a life cycle. Development applies to organism(s) acquiring a mature state, and differentiation applies to cells acquiring specialized functions. Keywords: development_or_differentiation_design
2005-07-16 | GSE2946 | GEO
Project description:Parasites grown as either tachyzoites or bradyzoites for 40 hours were pulsed with 2,4-dithiouracil (DTU) for 1 hour. Following the pulse, mRNA was extracted and either used directly in microarray experiments (Abundance Arrays) or biotinylated and purified to select DTU labeled RNAs that were then used in microarray experiments (Synthesis Arrays). Two independent tachyzoite and bradyzoite preparations were made and duplicate microarrays were performed for each sample. A development or differentiation experiment design type assays events associated with development or differentiation or moving through a life cycle. Development applies to organism(s) acquiring a mature state, and differentiation applies to cells acquiring specialized functions. User Defined
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Project description:Developmental switching in Toxoplasma gondii, from the virulent tachyzoite to the relatively quiescent bradyzoite stage, is responsible for disease propagation and reactivation. We have generated tachyzoite to bradyzoite differentiation (Tbd-) mutants in T. gondii and used these in combination with a cDNA microarray to identify developmental pathways in bradyzoite formation. Four independently generated Tbd- mutants were analysed and had defects in bradyzoite development in response to multiple bradyzoite-inducing conditions, a stable phenotype after in vivo passages and a markedly reduced brain cyst burden in a murine model of chronic infection. Transcriptional profiles of mutant and wild-type parasites, growing under bradyzoite conditions, revealed a hierarchy of developmentally regulated genes, including many bradyzoite-induced genes whose transcripts were reduced in all mutants. A set of non-developmentally regulated genes whose transcripts were less abundant in Tbd- mutants were also identified. These may represent genes that mediate downstream effects and/or whose expression is dependent on the same transcription factors as the bradyzoite-induced set. Using these data, we have generated a model of transcription regulation during bradyzoite development in T. gondii. Our approach shows the utility of this system as a model to study developmental biology in single-celled eukaryotes including protozoa and fungi.
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