Dataset Information

TgCrk2 interactome in Toxoplasma gondii RH and ME49 parasites

ABSTRACT: 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.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Toxoplasma Gondii Me49

TISSUE(S): Cell Culture, Fibroblast

DISEASE(S): Toxoplasmosis

SUBMITTER: Dale Chaput

LAB HEAD: Elena Suvorova

PROVIDER: PXD033109 | Pride | 2022-08-12

REPOSITORIES: Pride

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Publications

Restriction Checkpoint Controls Bradyzoite Development in Toxoplasma gondii.

Naumov Anatoli V AV Wang Chengqi C Chaput Dale D Ting Li-Min LM Alvarez Carmelo A CA Keller Thomas T Ramadan Ahmed A White Michael W MW Kim Kami K Suvorova Elena S ES

Microbiology spectrum 20220602 3

Human toxoplasmosis is a life-threatening disease caused by the apicomplexan parasite Toxoplasma gondii. Rapid replication of the tachyzoite is associated with symptomatic disease, while suppressed division of the bradyzoite is responsible for chronic disease. Here, we identified the T. gondii cell cycle mechanism, the G<sub>1</sub> restriction checkpoint (R-point), that operates the switch between parasite growth and differentiation. Apicomplexans lack conventional R-point regulators, suggestin ...[more]

PMID: 35652638

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Project description:Toxoplasma gondii is an obligate intracellular protozoan parasite whose rapid lytic replication cycles define its pathogenicity. We identified a temperature sensitive growth mutant, FV-P6, which irreversibly arrests before the middle of the G1 stage of the tachyzoite cell cycle. This arrest is caused by a point mutation in a gene conserved across eukaryotes, Cactin, whose product localizes to the nucleus. To elucidate the role of TgCactin we performed genome-wide expression profiling of FV-P6 mutant parasites at 35C and 40C, as well as FV-P6 complemented with a wild-type Cactin encoding cosmid (TOXO93 or comp) and as a pseudo-diploid wild-type line encoding both the wild-type and mutant Cactin locus (S4.2), also at both temperatures. Besides the expected G1 expression profile, many genes associated with the extracellular state as well as with the bradyzoite cyst stage were identified. Consistent with these profiles were the expression of AP2 transcription factors typically associated with extracellular and bradyzoite stage parasites. This suggests a role for TgCactin in control of gene expression. Since TgCactin does not contain any functionally defined domains we reasoned TgCactin exerts its function through interactions with other proteins. In support of this model we demonstrated that TgCactin is present in a protein complex and can oligomerize. Taken together, these results suggest that TgCactin acts as a pivotal protein potentially regulating gene expression at several transition points in parasite development. The role of Cactin in G1 progression of Toxoplasma gondii tachyzoites was assessed by expression profiling a temperature senstive mutant of Cactin at both the permissive (35C) as well as the restrictive (40C) temperature. Controls under the same temperature conditions inlcude the mutant line complemented with a wild-type Cactin allele encoded on a cosmid and a wild-type parasite line expressing an additional, mutant allele of Cactin (pseudo-diploid line).

Dataset Information

TgCrk2 interactome in Toxoplasma gondii RH and ME49 parasites

Publications

Restriction Checkpoint Controls Bradyzoite Development in Toxoplasma gondii.

Similar Datasets

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