Faculty and Staff

Dr. Nancy Trun
Associate Professor

B.S. Microbiology, Ohio State University, 1982
Ph.D. Molecular Biology, Princeton University, 1988
Post Doctorate, National Institutes of Health, 1993

Office Phone: (412) 396-1853
Email: trun@duq.edu

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Chromosome Folding, Microbial Genetics

Chromosomes are long very thin molecules that must be folded correctly in order to be functional and to fit inside of the cell. Using the model system E. coli, we have identified a family of small DNA binding proteins, called Csp proteins, which help fold the chromosome. We identified these proteins using the chromosome decondensing agent, camphor.

E. coli K-12 encodes nine csp genes that are expressed at different times during cell growth. Some are induced by cold shock, some by nutritional deprivation, some by stationary phase and some are expressed throughout the growth curve. The cell requires the presence of Csp proteins for viability, however no individual Csp has been shown to be essential.

We are currently studying:

1) The biochemistry of CspE to determine what nucleic acid substrates it will bind to and what the requirements for binding are.

2) The phenotypes associated with overproduction of CspE to determine the role(s) it plays in vivo.

3) The phenotypes associated with overproduction of each of the Csp proteins to determine if they all share the same role(s).

4) The phenotypes associated with deleting multiple csp genes to determine the minimum number required and the consequences for the cell.

5) Mutants in CspE that distinguish between its roles in gene regulation and the effects it has on DNA topography.

Selected Papers

1. Hu, K., Liu, E. Dean, K. Gingras, M., DeGraff, W. and Trun , N.J. Overproduction of three genes leads to camphor resistance and chromosome condensation in E. coli. Genetics 143:1521-1532, 1996.

2. Trun, N.J. and Marko, J. The architecture of a functional chromosome. ASM News. 64 (5): 276-283, 1998.

3. Sand, O., Gingras, M., Beck, N., Hall, C., and Trun , N.J. The E. coli chromosome condensing proteins, CrcA, CspE and CrcB can partially substitute for mutations in topoisomerase IV, MukB, Fis, IHF, HU and HNS in vivo. Microbiology 149:2107-2117, 2003.

4. Trun, N.J. and Johnston, D. Folding chromosomes in bacteria: Examining the role of Csp proteins and other small nucleic acid-binding proteins. Current Topics in Develop. Biology 55:173-201, 2003.

Textbook

Fundamental Bacterial Genetics. N. Trun and J. Trempy. Blackwell Publishing. Malden , MA. 2004.