Washington University
School of Medicine

Dept. of Pediatrics &
Dept. of Molecular Microbiology
Box 8208
660 S. Euclid Ave.
St. Louis, MO 63110

tel: (314) 286-2912
fax: (314) 286-2895
email: McKinney_J@wustl.edu
web: Personal Weblink

Our laboratory is interested in the pathogenesis of bacterial infections and we are using novel techniques of bacterial gene regulation to dissect host-pathogen interactions. The laboratory is investigating the effects of dynamically modulating virulence gene expression in E. coli and pathogenic Salmonella, using these bacteria as models of gram negative pathogens responsible for a wide range of serious infections. To modulate gene expression, the lab employs a system of inducible gene product disruption, involving RNA molecules called external guide sequences (EGSs) which target specific mRNA for cleavage by cellular RNase P.

Past work using this system to down-regulate E. coli genes essential to bacterial viability has shown the molecular and cellular effects of EGSs exhibit reproducible time course dynamics, dose-response, and synergy and are EGS oligonucleotide sequence specific. Using a new Salmonella strain allowing for the dynamic control of EGS expression triggered by various sugars, recent work focuses on genes in the Salmonella SPI-1 pathogenicity island, including the invB and invC genes involved in Salmonella's invasion of host cells. The laboratory is seeking to dissect the functions of, and dynamic interactions between, pathogenicity genes in invasion and subsequent disease.

In ongoing work, the laboratory is taking advantage of the fact that the RNase P enzyme is a ribozyme, in which RNA is catalytically active. To this end, the lab is designing new RNA molecules allowing for further analysis of the molecular mechanisms of EGS effects in Salmonella, including new molecules amenable to in vitro evolution and to studies of RNA biology in bacteria.

Potential implications of these research efforts include gaining insights to help develop new antimicrobial agents and strategies designed to counter bacterial drug resistance, and to better understand the various functions of RNA molecules in bacteria.

McKinney J, Guerrier-Takada C, Wesolowski D and Altman S: Inhibition of Escherichia coli viability by external guide sequences complementary to two essential genes. Proc Natl Acad Sci U S A. 2001; 98(12):6605-10.

McKinney J, Guerrier-Takada C, Galan J and Altman S: Tightly regulated gene expression system in Salmonella enterica serovar Typhimurium. J Bacteriol 2002; 184:6056-9.

McKinney JS, Zhang H, Kubori T, Galan JE, and Altman S: Disruption of type III secretion in Salmonella enterica serovar Typhimurium by external guide sequences. Nucleic Acids Res. 2004;32(2):848-54.