Martin Freundlich
Ph.D., University of Minnesota, 1961
Professor, Department of Biochemistry and Cell Biology
Research Interests: Regulation of gene expression in prokaryotes by interacting
transcription factors.
Our overall goal is to understand on the molecular level how the expression
of individual genes is integrated into the total metabolism of the cell
during altered physiological states. To this end we are investigating the
interaction of a DNA binding protein, integration host factor (IHF), with
numerous E. coli promoters. Current work is focused on two projects.
1) A major role for IHF in gene expression in E. coli. We have used 2-D
gel electrophoresis of total E. coli proteins and in vitro binding and transcription
analysis to show that IHF alters the expression of an unusually large number
of genes in E. coli. Ongoing studies suggest that IHF belongs to a new class
of DNA binding proteins that change DNA conformation to allow for proper
functioning of other transcription factors.
2) The role of IHF in expression of the omp operons. These operons mediate
the expression of OmpF and OmpC, the major E. coli porin proteins that are
transcriptionally regulated by a signal transducton system that senses growth
medium osmolarity. IHF binds to and bends omp promoter DNA and modulates
osmoregulation. We are currently investigating the precise molecular mechanism
of how IHF interacts with this signal transduction system to alter transcription.
Sirko, A., Sawers, G., Zehelein, M. and Freundlich, M. (1993) IHF is required
for anaerobic pyruvate induction of pfl operon expression in E. coli. J.
Bacteriol. 175: 5769-5777.
Ramani, N., Hedeshian, M. and Freundlich, M. (1994) MicF antisense RNA has
a major role in E. coli. J. Bacteriol., (in press).
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