The Repository @ St. Cloud State

Open Access Knowledge and Scholarship

Date of Award


Culminating Project Type


Degree Name

Biological Sciences - Cell and Molecular: M.S.




College of Science and Engineering

First Advisor

Christopher Kvaal

Second Advisor

Timothy Schuh

Third Advisor

Nathan Bruender

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Keywords and Subject Headings

Toxoplasma gondii, cyclin, yeast two hybrid screen, cyclin dependent kinase


In this current research, protein-protein interactions with a putative Toxoplasma gondii cyclin, TGME49_266900 or "Cyc6," were discovered via a yeast two hybrid screen. Several putative interacting protein partners were isolated and described from a cDNA library of an asynchronous tachyzoite transcriptome. After false positives were weaned from the study, two proteins were identified as Cyc6 interacting partners. These two proteins are described from the bioinformatic database as a DJ-1 family protein (TGME49_214290) and a ThiF protein (TGME49_314890). Interestingly, the interacting DJ-1 protein has been shown in previous research to play a role in T. gondii microneme secretion. Additionally, ThiF proteins share distinct traits with E1 enzymes at the start of the ubiquitin pathway in eukaryotes. After no evidence of an interacting CDK partner for Cyc6 was obtained, a direct experiment was conducted testing for an interaction between Cyc6 and a putative CDK with expression levels notably higher in bradyzoites instead of tachyzoites. The outcome of this experiment showed no interaction between Cyc6 and the putative CDK. Although no interacting CDK partner was evident from this yeast two hybrid screen, two proteins were found to display a strong and biologically relevant interaction with the putative cyclin of interest. Future studies regarding Cyc6 should explore potential noncanonical roles for this putative cyclin in not only tachyzoites, but also bradyzoites and the purpose of Cyc6's interaction with the two proteins discovered from this screen.



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