Submission Date


Document Type

Paper- Restricted to Campus Access



Faculty Mentor

Christina Kelly

Second Faculty Mentor

Dale Cameron


Presented during the 20th Annual Summer Fellows Symposium, July 20, 2018 at Ursinus College.

Supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number R15GM119081.

Project Description

Proteins are chains of amino acids that play vital roles in most cellular functions. The three-dimensional conformation in which a protein folds determines its function, therefore proper protein folding is crucial to life and has been shown to be defective in a growing number of diseases. Some proteins, however, can misfold into prions. Prions are self-propagating infectious misfolded proteins that can aggregate within the cell and cause disruptions in cellular function. In S. cerevisiae, the protein Sup35 is a translation termination factor that can misfold into the [PSI+] prion. Misfolded Sup35 leads to incorrect termination of protein synthesis and the production of extended proteins. The Ribosome Associated Complex (RAC), consisting of the proteins Zuo1, Ssb1, and Ssz1, is bound to the ribosome and acts as a molecular chaperone to help proteins fold into their correct conformations as they are synthesized by the ribosome. Loss of RAC function leads to increased conversion to [PSI+]. Additionally, previous research has shown that Zuo1, one component of the RAC, is also involved in the activation of pleotropic drug resistance response (PDR), which activates genes that code for proteins that can help the cell survive in a high stress environment. In the present study, the role of Zuo1 in prion formation under various stress conditions is assessed using a GFP-based reporter system, where the level of GFP expression corresponds to the level of [PSI+] formation. GFP fluorescence was measured by Flow Cytometry and fluctuation analysis was used to analyze the data.