Expression data from Toxoplasma gondii mutants and wild-type during bradyzoite differentiation in vitro
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ABSTRACT:
ORGANISM(S): Toxoplasma gondii
SUBMITTER: Mariana Matrajt
PROVIDER: E-GEOD-23174 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Toxoplasma gondii pathogenesis includes the invasion of host cells by extracellular parasites (tachyzoites), replication of intracellular tachyzoites, and differentiation to a latent bradyzoite stage. Whole genome expression profiling was carried out using the newly developed Affymetrix ToxoGeneChip (GeneChip Tgondiia520372) in order to analyze the ~8,000 predicted genes in the T. gondii genome of mutants and wild-type, allowing for full-scale expression profiling during bradyzoite differentiation in vitro.
2010-07-27 | GSE23174 | GEO
Project description:Although apicomplexans lack conventional R-point regulators, presence of the quiescent G1 forms of 43 parasites, including mature T. gondii bradyzoites suggests that a functional RESTRICTION checkpoint 44 exists in apicomplexan parasites. We showed that Cdk-related G1 kinase TgCrk2 forms alternative 45 complexes with atypical cyclins (TgCycP1, TgCycP2 and TgCyc5) in the rapidly dividing developmentally 46 incompetent RH and slower dividing developmentally competent ME49 tachyzoites and bradyzoites. 47 Examination of individual cyclins verified the correlation of cyclin expression with growth dependence and 48 development capacity of type I RH and type II ME49 strains. We demonstrated that rapidly dividing RH 49 tachyzoites are dependent on TgCycP1 and expression of TgCycP1 interferes with bradyzoite 50 differentiation. By using an auxin-induced degradation (AID) model, we established that TgCycP2 51 regulates G1 duration in the developmentally competent ME49 tachyzoites but not in the developmentally 52 incompetent RH tachyzoites. We also tested the functions of TgCycP2 and TgCyc5 in alkaline induced in 53 vitro model and in ex vivo model of spontaneous bradyzoite differentiation (rat embryonic brain cells). 54 Based on functional and global gene expression analyses, we determined that TgCycP2 also regulates 55 bradyzoite replication, while stress- or host-induced TgCyc5 was critical for efficient bradyzoite conversion 56 and tissue cyst maturation.
2022-08-12 | PXD033109 | Pride
Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions.
2005-07-21 | E-SMDB-1406 | biostudies-arrayexpress
Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. User Defined
2005-08-13 | E-GEOD-3119 | biostudies-arrayexpress
Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-13 | GSE3119 | GEO
Project description:Parasitic protozoa such as the apicomplexan Toxoplasma gondii progress through their life cycle in response to stimuli in the environment or host organism. Very little is known about how proliferating tachyzoites reprogram their expressed genome in response to stresses that prompt development into latent bradyzoite cysts. We have previously linked histone acetylation with the expression of stage-specific genes, but the factors involved remain to be determined. We sought to determine if GCN5, which operates as a transcriptional co-activator by virtue of its histone acetyltransferase (HAT) activity, contributed to stress-induced changes in gene expression in Toxoplasma. In contrast to other lower eukaryotes, Toxoplasma has duplicated its GCN5 lysine acetyltransferase (KAT). Disruption of the gene encoding for TgGCN5-A did not produce a severe phenotype under normal culture conditions, but here we show that the TgGCN5-A null mutant is deficient in recovering from alkaline pH, a common stress used to induce bradyzoite differentiation in vitro. The TgGCN5-A knockout is incapable of up-regulating key marker genes expressed during development of the latent cyst form. Complementation of the TgGCN5-A knockout restores the expression of these stress-induced genes and reverses the stress recovery defect. We also describe a genome-wide analysis of the Toxoplasma transcriptional response to alkaline pH stress, finding that TgGCN5-A knockout parasites fail to up-regulate 68% of the stress response genes that are induced 2-fold or more in wild-type. Using chromatin immunoprecipitation, we verify an enrichment of TgGCN5-A at the upstream regions of genes activated by alkaline pH exposure, including developmentally regulated genes. Wild-type and GCN5-A- Knockout organisms were subjected to control and stress treatments
2011-05-25 | E-GEOD-22100 | biostudies-arrayexpress
Project description:Toxoplasma gondii persists in humans by converting from actively replicating acute stage tachyzoites to slow-growing chronic stage bradyzoites. The molecular mechanisms that mediate T. gondii differentiation remain poorly understood. Through a chemical mutagenesis screen, we identified translation initiation factor eIF1.2 as being critical for T. gondii differentiation. The presence of an F97L mutation in eIF1.2 identified in the screen or the complete lack eIF1.2 (∆eIF1.2) markedly impeded bradyzoite cyst formation in culture and in the brains of infected mice. ∆eIF1.2 parasites were defective in the upregulation of bradyzoite differentiation regulators BFD1 and BFD2 during stress-induced differentiation. Conditional overexpression of BFD1 or BFD2 rescued differentiation in ∆eIF1.2 parasites. We further show that eiF1.2 interacted with the yeast 40S ribosome and directed the scanning of a model 5’ untranslated region. Together, our findings imply that eIF1.2 functions by regulating the translation of key differentiation factors necessary to establish T. gondii chronic infection.
2024-04-10 | GSE245775 | GEO
Project description:The protozoan pathogen Toxoplasma gondii has the unique ability to develop a chronic infection in the brain of its host. The T. gondii develops cysts within the neurons that are resilient against the host immune response and current therapeutics. The bradyzoite parasites within the cyst have a sugar-protein-rich wall and a slow-replication cycle, allowing them to remain hidden from the host. This intracellular encysted lifestyle of T. gondii has made them recalcitrant to molecular analysis in vivo. Here, we have enriched for T. gondii brain cysts 21 to 150 days post-infection (DPI). RNA and protein from bradyzoites was isolated from each timepoint. Deep sequencing of transcripts expressed during these three timepoints showed many of the identified proteins are transcriptionally expressed at a high level. Approximately one-third are more enriched during bradyzoite conditions compared to tachyzoites, and approximately half are expressed at similar levels during each phase. We have expanded the transcriptional profile of in vivo bradyzoites to 120 DPI. The RNA sequencing depth of in vivo bradyzoite T. gondii was over 250-fold greater than was have been previously, which allowed us to identify low level transcripts and novel bradyzoite-specific isoforms.
2019-07-11 | GSE134099 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE11437: Expression QTL mapping of Toxoplasma gondii genes, Bradyzoite array GSE11514: Expression QTL mapping of Toxoplasma gondii genes, Tachyzoite array Keywords: SuperSeries Refer to individual Series
2008-05-22 | E-GEOD-11515 | biostudies-arrayexpress
Project description:Plasmodium and Toxoplasma are parasites of major medical importance that belong to the Apicomplexa phylum of protozoa. These parasites transform into various stages during their life cycle and express a specific set of proteins at each stage. Although still little is known of how gene expression is controlled in Apicomplexa, histone modifications, particularly acetylation, are emerging as key regulators of parasite differentiation and stage conversion. Here, we investigated the anti-Apicomplexa effect of FR235222, a histone deacetylase (HDAC) inhibitor. We show that FR235222 is active against a variety of Apicomplexa genera, including Plasmodium and Toxoplasma, and is more potent than other HDACi such as TSA and the clinically relevant compound, pyrimethamine. We identify TgHDAC3 as the target of FR235222 in Toxoplasma tachyzoites and demonstrate the crucial role of the conserved and Apicomplexa HDAC-specific residue TgHDAC3 T99 in the inhibitory activity of the drug. We also show that FR235222 induces differentiation of the tachyzoite (replicative) into the bradyzoite (non replicative) stage. Additionally, via its anti-TgHDAC3 activity, FR235222 influences the expression of ~370 genes, a third of which are stage-specifically expressed. These results identify FR235222 as a potent HDAC inhibitor of Apicomplexa, and establish HDAC3 as a central regulator of gene expression and stage conversion in Toxoplasma and likely other Apicomplexa. Freshly released tachyzoites were needle-passed, and filtered using a 3-µm nucleopore membrane. Parasites were resuspended into fresh DMEM supplemented with 10% (v/v) FBS and 25 mM HEPES buffer pH7.2. Parasites were incubated in the presence of FR235222 (40 nM) or DMSO (0.1%) for 4 h at 37°C with 5% CO2. For ChIP-chip experiments freshly released tachyzoites (~5 x 109 at ~12 x 107 parasites/mL) were fixed for 15 min in 1% formaldehyde. Increase in AcH4 signals was verified by immunoblot to verify that FR235222 treatment was effective. To prepare chromatin samples, fixed parasites were lysed in MNase buffer (0.32 M Sucrose, 50 mM Tris-HCl pH7.8, 4 mM MgCl2, 3 mM CaCl2, 100 mM NaCl, 0.25% (v/v) NP40, 5% (v/v) glycerol, protease inhibitor EDTA-free cocktail (Roche)) and DNA was digested for 4 min at 37°C by MNase (2 units/mL). Digestion was stopped with 20 mM EDTA and chromatin was recovered in the soluble fraction after centrifugation at 10,000 g at 4°C; this constituted the S1 fractions. Pelleted materials were resuspended in dialysis buffer (1mM Tris-HCl pH7.8, 0.2 mM EDTA) containing 1 mM PMSF and protease inhibitor cocktail (Roche®) and dialyzed overnight at 4°C against the same solution. Then dialyzed materials were centrifuged and supernatant were harvested; this constitutes the S2 fractions. For chromatin immunoprecipitations, fractions S1 and S2 were pooled and DNA quality was verified by electrophoresis on 2% agarose gels; oligonucleosome ladder of 100-1000 bp were obtained. The histone-DNA complexes were immunoprecipitated with anti-acetyl histone H4 (Upstate®, catalog # 06-866) antibodies according to NimbleGenâs protocol (http://www.genomecenter.ucdavis.edu/expression_analysis/documents).
2010-06-21 | E-GEOD-15241 | biostudies-arrayexpress