Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Jennifer Gallagher

Committee Member

Daniel Panaccione

Committee Member

Sadie Bergeron


Hydrotropes are small molecules capable of inducing liquid-liquid phase separation by altering the solubility and conformation states of organic compounds that are increasingly becoming important in organizing chemical reactions and regulating complexes. They prevent protein aggregation causing these proteins to form condensates. Mediator, a highly conserved multi-subunit complex, plays an important role in transcription. Med15, a subunit found within the tail domain of the Mediator complex, works with stress-induced transcription factors and is regulated by many kinases, including CDKs and the AMP kinase, Snf1. Living cells respond by changing molecular and cellular pathways when they are exposed to stressful conditions. Damage to intracellular molecules depends on the duration of stress exposure and the severity of the stressor. By studying cellular stress response through the Mediator complex in Saccharomyces cerevisiae, the molecular effects of MCHM (4-methylcyclohexanemethanol), a synthetic hydrotrope, can be determined. The hydrotropic nature of MCHM and how it interacted with the polymorphic polyQ tracts of Med15 likely caused protein folding aggregation, which eventually led to protein condensates. The tolerance towards MCHM and other chemical stressors such as 4-nitroquinoline-1-oxide (4NQO), hydrogen peroxide (H2O2), and hygromycin (HYG) are dependent on the genetic variation of Med15’s polyQ tract and the presence of Snf1. Genetic variations of Med15 influence the formation of LLPS by affecting how the fuzzy domains, which include the polyQ tracts of the subunit, interact with hydrotropes. These findings combined to characterize how different alleles of Med15 deal with stress-inducing conditions by studying its interactions with a hydrotrope like MCHM.