Toxoplasma gondii
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ABSTRACT:
PROVIDER: PRJNA128921 | ENA |
REPOSITORIES: ENA
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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: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.
2011-05-25 | GSE22100 | GEO
Project description:Two samples, 0hr and 72hr, were used to generate tachyzoite and bradyzoite transcriptional data from tissue-cultured Toxoplasma gondii strain Prugniaud, respectively. Samples are single replicates, and a subset of a larger timeseries. Non-control sample was exposed to alkaline conditions, media pH 8.2, for 72hr.
2010-06-15 | E-GEOD-22258 | biostudies-arrayexpress
Project description:The Toxoplasma gondii G1 RESTRICTION checkpoint operates the switch between parasite growth and differentiation. The Cdk-related G1 kinase TgCrk2 forms alternative complexes with atypical cyclins (TgCycP1, TgCycP2 and TgCyc5) in the rapidly dividing developmentally incompetent RH and slower dividing developmentally competent ME49 tachyzoites and bradyzoites. The TgCycP1 expression interferes with bradyzoite differentiation. The TgCycP2 regulates G1 in the developmentally competent ME49 but not in the developmentally incompetent RH tachyzoites. Examination of TgCycP2 and TgCyc5 in alkaline induced and spontaneous bradyzoite differentiation (rat embryonic brain cells) models confirmed TgCycP2 role in bradyzoite replication and revealed that stress induced TgCyc5 is critical for efficient tissue cyst maturation.
2022-04-23 | GSE200962 | GEO
Project description:The acute-to-chronic stage transition in Toxoplasma gondii involes a global restructuring of the parasite transcriptome and is induced under alkaline stress. We found that parasites lacking the RNA-binding protein BFD2 are unable to produce chronic forms, consistent with a block in this develomental program. To understand how BFD2 facilitates chronic-stage transcriptional reprogramming in T. gondii, we profiled the transcriptomes of both 'wildtype' and BFD2-knockout parasites under alkaline-stressed and standard culture conditions
2023-03-31 | GSE223869 | GEO
Project description:Cyst formation is a key feature of the T. gondii life cycle but the genetic networks that drive this process are not yet fully characterized. To identify new components of this network, we compared T. gondii to its nearest extant relative Hammondia hammondi given the critical differences between these species in the timing and efficiency of cyst formation. Using transcriptional data from critical developmental and pH exposure time points from both species, we identified the gene TGVEG_311100, which we named Regulator of Cystogenesis 1 (ROCY1), as being both necessary and sufficient for cyst formation in T. gondii. Compared to WT parasites, TGVEG?ROCY1 parasites formed significantly fewer tissue cysts in response to alkaline pH stress in vitro and cysts were nearly undetectable in mouse brains for up to 9 weeks post-infection. Overexpression of tagged ROCY1 in WT parasites was sufficient to induce cyst formation in vitro in both WT and ROCY1-deficient parasites, demonstrating that ROCY1 is both necessary and sufficient for cyst formation. Moreover this induction of cyst formation required at least 1 of 3 predicted CCCH Zinc finger domains. Mice chronically infected with ?ROCY1 parasites had detectable tachyzoites in the brain for up to 37 days post-infection (while mice infected with WT parasites did not), and CNS transcriptional analyses at day 30 post-infection throughout the chronic phase of infection revealed inflammatory signatures consistent with acute infection in ?ROCY1 parasites compared to WT. Despite our inability to detect brain cysts in infected mice, both WT and ?ROCY1 knockout parasites reactivated after dexamethasone treatment with similar timing and magnitude for up to 5 months post infection, challenging the paradigm that long term parasite persistence in the CNS requires cyst formation. These data identify a new regulator of cyst formation in T. gondii that is both necessary and sufficient for cyst formation, and whose function relies on its conserved nucleic acid binding motif.
2023-08-11 | GSE211957 | GEO
Project description:Recent advances in high throughput sequencing methodologies allow the opportunity to probe in depth the transcriptomes of organisms including N. caninum and Toxoplasma gondii. In this project, we are using Illumina sequencing technology to analyze the transcriptome (RNA-Seq) of experimentally accessible stages (e.g. tachyzoites at different times points) of T. gondii VEG strain. The aim is to make comparative transcriptional landscape maps of Neospora and Toxoplasma at different time points at different life cycle stages and compare levels of expression of orthologous genes in these two organisms.
2011-02-08 | E-MTAB-550 | biostudies-arrayexpress
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