Date of Award


Publication Type

Master Thesis

Degree Name



Chemistry and Biochemistry


Ananvoranich, Sirinart




Argonaute protein is a vital component in the RNA interference pathway and post-transcriptional gene regulation in eukaryotes and the protein was recently identified in Toxoplasma gondii. However, the molecular mechanism by which the argonaute protein participates in regulating gene regulation pathways is unclear. This study was aimed to investigate the presence of argonaute protein variants in T. gondii (TgAgo), and its contribution in post-transcriptional gene silencing pathway. Furthermore, the study was designed to elucidate the influence of TgAgo on parasite growth and bradyzoite development. Using PCR analysis, I did not detect any transcript variants of TgAgo. A single transcript of TgAgo was identified to have 2,232 nucleotides encompassing 5 exons. Protein immunoblot assay showed a single protein of ~58.5 kDa. Gene silencing assays demonstrated that knockout of argonaute expression (AGOKO) reduced the gene silencing ability of an RNAi-like mechanisms in T. gondii, suggesting the importance of TgAgo in post transcriptional gene regulation pathways. T. gondii growth pattern was unaffected by the removal of Ago expression. However, bradyzoite formation was increased in AGOKO strains. The study suggests that TgAgo is a vital component of bradyzoite formation in the life cycle of T. gondii.