Exploring Evolution: I. Directing Evolution of Proteins with Phage, II. Examining the Effects of Toxic Quantum Dots on the Yeast Genome

This thesis comprises two separate directed evolution studies. Part I describes the optimization of a reporter construct for the protein evolution tool, PACE. Myc is a transcriptional activator and oncoprotein associated with more than half of all human cancers. Our aim is to use PACE to develop DNA-binding proteins that compete with Myc binding to E-box DNA and inhibit Myc-mediated activation. We employed a bacterial one-hybrid system to test E-box reporter constructs and identified seven constructs that could serve as potential PACE precursors.;Part II explores the effects of toxic nanoparticles on the yeast genome. We showed that Saccharomyces cerevisiae populations evolve to survive chronic exposure to CdSe quantum dots (QDs). Genetic analysis of evolved cells confirmed one mutation in bul1 that was implicated in increased tolerance for QDs. This is the first demonstration that chronic QD exposure can lead to irreversible genetic changes and adaptation.