UW-Madison Dept of Bacteriology

Research Focus

We study the molecular biology of gene expression in bacteria, primarily the mechanism of transcription initiation, the architecture of transcription complexes, the relationship between structure and function in subunits of RNA polymerase (RNAP), and the mechanisms by which the transcription apparatus responds to signals from inside and outside of the cell. We focus on ribosomal RNA transcription and the control of ribosome synthesis in Escherichia coli, because ribosome synthesis is of central importance to cell function, because rRNA promoters account for the majority of transcription in the cell, and because rRNA promoters display a fascinating, complex network of regulatory responses. Current projects in the lab include studies on Fis, a transcription factor that recruits RNAP to the rRNA promoter, studies on the C-terminal domain of the alpha subunit of RNAP and how it accounts for the extraordinary strength of rRNA promoters, studies of how the characteristic short half-life of the rRNA promoter complex with RNAP makes these promoters susceptible to regulation by changing NTP and ppGpp concentrations, and studies on newly-identified factors that affect rRNA transcription. We have also begun to use the tools of cell biology to explore the possibility that bacteria have nucleoli (i.e. a specific location where rRNA operons come together in the bacterial nucleoid).