Physics Colloquium - Friday, October 2nd, 2009, 4:00 P.M.

Justin Gallivan
Department of Chemistry and
Center for Fundamental and Applied Molecular Evolution
Emory University

Simple organisms, such as the bacterium E. coli., carry out a wide variety of complex chemical tasks. E. coli cells synthesize complex molecules, communicate with one another, move in response to changing conditions, and replicate themselves every 20 minutes. The programs that control these behaviors are encoded in a genome so small that its entire information content can be stored on a 3.5-inch floppy disk with room to spare. In this talk, I will present our recent efforts to reprogram E. coli to sense new small molecules and to respond to them with predictable behaviors. Specifically, I will describe our efforts to create synthetic riboswitches, which are designer RNA sequences that control gene expression in a ligand-dependent fashion without the need for proteins. I will show how synthetic riboswitches can be used to engineer bacteria to have a variety of functions, including the ability to seek and destroy small molecules. Finally, I will show how synthetic riboswitches are useful tools for studying the genetics of a variety of different bacteria.