The bacterial cell coordinates the 2OOO individual chemical reactions necessary for its growth and survival by controls that operate above the level of the individual operon. Many operons, though scattered on the genetic map, are organized as systems of genes (regulons) sharing a common regulatory molecule. This project explores the regulons involved in the global response of Escherichia coli to high temperature, to low temperature, and to phosphate starvation. (i) A shift to high temperature (42 degree C) induces a set of 18 heat-shock genes. This response system is one of the most ancient regulons, and its near universal retention throughout biology speaks to some essential but still unknown role common to cells from bacterial to human. Heat-shock function will be studied by identifying the products of individual heat-shock genes and learning their functions, and by studying mutant cells defective in the heat-shock response or genetically engineered cells to produce a heat-shock response upon artificial induction. (ii) A shift to low temperature (10 degree C) induces a different set of proteins, including polynucleotide phosphorylase, NusA, translation initiation factors 2 alpha and 2 beta, and a very prominently induced 10kd protein of unknown identity. Analysis of this cold shock response is designed to learn how E. coli adapts to low temperature, to discover whether the cold-shock induced proteins form a regulon, and to answer some long standing questions about the function and regulation of these proteins, particularly concerning the coupling of transcription and translation during growth. (iii) Starvation for phosphate induced approximately 100 proteins in E. coli, some of which are governed by multiple genes whose products serve as sensors and regulators. By measuring the total cellular protein response to phosphate limitation in mutants defective in one or more element of this complex regulatory system, the regulon organization of the response will be analyzed, and its multiple functions studied. This study should help in understanding how regulons coordinate gene expression for growth and for survival of E. coli in the face of environmental stress, and should provide valuable leads to metabolic integration and gene coordination in more complete cells. ln addition, the heat-shock response has human medical implications for bacterial and virus infections, for environmentally induced birth defects, for tumor chemotherapy, and for cell responses to environmental stress.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM017892-23
Application #
3269156
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1978-09-01
Project End
1994-08-31
Budget Start
1992-09-01
Budget End
1994-08-31
Support Year
23
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Peruski Jr, L F; Neidhardt, F C (1994) Identification of a conditionally essential heat shock protein in Escherichia coli. Biochim Biophys Acta 1207:165-72
Nystrom, T; Neidhardt, F C (1994) Expression and role of the universal stress protein, UspA, of Escherichia coli during growth arrest. Mol Microbiol 11:537-44
Welch, T J; Farewell, A; Neidhardt, F C et al. (1993) Stress response of Escherichia coli to elevated hydrostatic pressure. J Bacteriol 175:7170-7
Nystrom, T; Neidhardt, F C (1993) Isolation and properties of a mutant of Escherichia coli with an insertional inactivation of the uspA gene, which encodes a universal stress protein. J Bacteriol 175:3949-56
Gage, D J; Neidhardt, F C (1993) Adaptation of Escherichia coli to the uncoupler of oxidative phosphorylation 2,4-dinitrophenol. J Bacteriol 175:7105-8
Gage, D J; Neidhardt, F C (1993) Modulation of the heat shock response by one-carbon metabolism in Escherichia coli. J Bacteriol 175:1961-70
Jones, P G; Cashel, M; Glaser, G et al. (1992) Function of a relaxed-like state following temperature downshifts in Escherichia coli. J Bacteriol 174:3903-14
Nystrom, T; Neidhardt, F C (1992) Cloning, mapping and nucleotide sequencing of a gene encoding a universal stress protein in Escherichia coli. Mol Microbiol 6:3187-98
Lin, R; Ernsting, B; Hirshfield, I N et al. (1992) The lrp gene product regulates expression of lysU in Escherichia coli K-12. J Bacteriol 174:2779-84
VanBogelen, R A; Sankar, P; Clark, R L et al. (1992) The gene-protein database of Escherichia coli: edition 5. Electrophoresis 13:1014-54

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