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Updated: Aug 11, 2026
09:52
Genetic Manipulation in Δku80 Strains for Functional Genomic Analysis of Toxoplasma gondii
Published on: July 12, 2013
Two genes encoding unique proliferating-cell-nuclear-antigens are expressed in Toxoplasma gondii
1Department of Veterinary Molecular Biology, Marsh Laboratory, Montana State University, Bozeman 59717-3610, USA.
Molecular and Biochemical Parasitology
|August 26, 2000
Summary
Two novel proliferating cell nuclear antigen genes (TgPCNA1 and TgPCNA2) were identified in Toxoplasma gondii, suggesting a gene duplication event in apicomplexan parasites. Differential mRNA expression indicates independent gene control despite similar protein levels.
Area of Science:
- Molecular Parasitology
- Genomics
- Cell Biology
Background:
- Proliferating cell nuclear antigens (PCNAs) are crucial for DNA replication and repair.
- Understanding PCNA diversity in apicomplexan parasites like Toxoplasma gondii is essential for comprehending their unique biological processes.
Purpose of the Study:
- To identify and characterize novel PCNA genes in Toxoplasma gondii.
- To investigate the evolutionary relationship of T. gondii PCNAs with those from other apicomplexans, specifically Plasmodium falciparum.
- To analyze the expression patterns of T. gondii PCNA genes at both mRNA and protein levels.
Main Methods:
- cDNA library screening and sequencing to isolate TgPCNA1 and TgPCNA2.
- Southern blot analysis to confirm gene presence in genomic DNA.
- Sequence comparison and phylogenetic analysis with Plasmodium falciparum PCNAs.
- Western blot analysis using specific antibodies to detect protein expression.
- Northern blot analysis to assess mRNA expression levels and species.
Main Results:
- Two distinct PCNA genes, TgPCNA1 and TgPCNA2, were identified in T. gondii.
- TgPCNA1 and TgPCNA2 showed distinct amino acid identities with Plasmodium falciparum PCNAs (PfPCNA1 and PfPCNA2), suggesting a gene duplication in a common ancestor.
- Both TgPCNA1 and TgPCNA2 proteins were expressed at similar levels across different T. gondii strains.
- TgPCNA1 exhibited higher mRNA expression levels and multiple mRNA species compared to TgPCNA2, which had a single mRNA species.
Conclusions:
- The presence of two PCNA genes in T. gondii likely resulted from a gene duplication event in the ancestral apicomplexan lineage.
- Differential mRNA expression of TgPCNA1 and TgPCNA2 suggests independent transcriptional regulation.
- Post-transcriptional mechanisms may contribute to the equalization of TgPCNA1 and TgPCNA2 protein levels despite differing mRNA profiles.
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