Professor in Molecular Genetics & Microbiology
Main Office: NMS 1.116
Phone: (512) 471-3143
Alternate Office: NMS 1.210
Alt. Phone: (512) 471-0773
The University of Texas at Austin
Section of Molecular Genetics and Microbiology
2506 Speedway Stop A5000
Austin ,TX 78712-1191
Our major interest is understanding how nucleic acids pass through lipid bilayers. Our model system is bacteriophage T7, which uses three different motor proteins to transport its DNA into the cell at the initiation of infection. The phage ejects proteins into the cell that make a channel for DNA transport across the cell envelope and constitute the first molecular motor. We are characterizing this channel and motor with the aim of reconstructing a DNA translocation system in vitro. The second and third motors are RNA polymerases that transport the T7 genome into the cell by transcription. We use the “genome entry” assay to measure kinetics of transcription in vivo. A current focus is a transcription anti-termination system that enhances the rate of genome entry and makes infection more efficient. We are exploring ways to measure the transport kinetics of other phage genomes, in particular lambda, into the cell.
Other interests include various host-parasite interactions; currently we are determining the molecular basis for exclusion of T7 by cells containing the F plasmid, evaluating
phages for use in phage therapy protocols, using phages as models in evolutionary genetics, and phage genomics. A more specific project underway is to determine the mechanism by which transcription of the T7 genome is switched from catalysis by E. coli to the phage RNAP. Two T7 proteins: gp0.7 and gp2, are involved; in their absence the phage undergoes an abortive infection where the phage genome is degraded. We are analyzing rare mutants that bypass the requirement for these proteins, anticipating that we will uncover a novel regulatory genetic network for phage development.