The research in this laboratory is designed to reveal the fundamental mechanisms that facilitate positive and negative eukaryotic gene regulation on the molecular level. We primarily use a biochemical approach to dissect and then reconstitute these processes from purified proteins and nucleic acids as a starting point for mechanistic studies. Studying transcription in the yeast Saccharomyces cerevisiae allows us to utilize a combination of genetic, genomic, biochemical, chemical and structural techniques to understand exactly how transcriptional activators and repressors work in eukaryotic cells. My previous research has demonstrated the absolute requirement for the 20 protein yeast Mediator complex in activated transcription using a system reconstituted from pure proteins and in vivo (a physically and functionally homologous complex has recently been characterized in mammalian cells). Starting from this work our current research focuses on purification and characterization of additional factors that influence Mediator dependent transcription, a detailed genetic and biochemical analysis of Med7 (the most widely conserved and utilized Mediator subunit), and the reconstitution of negative regulation of transcription from purified factors. Meeting many of these challenges will also involve assembling chromatin templates for in vitro functional assays that better reflect the environment in the cell.