The long-term goal of this research is elucidation of the molecular mechanisms that accomplish the propagation and inheritance of extrachromosomal genetic elements in populations of growing cells. More particularly, the research is intended to further an understanding of how the products of plasmid DNA replication are segregated (i.e., are partitioned) into daughter cells at the time of cell division.
The specific aims of the project are: 1) to critically evaluate the hypothesis that stabilization of plasmid inheritance by the pSC101 par region results at least in part from the ability of this locus to locally increase DNA superhelicity and consequently promote formation of the DNA protein complex that initiates replication, 2) to elucidate the process by which DNA superhelicity affects such complex formation, 3) to investigate the mechanism by which the par region of pSC101 promotes the physical association of plasmid DNA with the bacterial cell membrane, and 4) to identify host proteins involved in this interaction. This multifaceted project, which will utilize a combination of genetic and biochemical approaches to achieve its goals, will focus on the pSC101 plasmid as a model system. The project, which represents the continuation of ongoing investigations of plasmid partitioning, addresses questions of practical as well as fundamental, importance; plasmids can encode harmful traits such as toxin production, virulence, and antimicrobial resistance --- and the mechanisms responsible for stable plasmid inheritance thus have substantive health-related implications.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM026355-12
Application #
3273851
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1979-07-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
12
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Stanford University
Department
Type
Schools of Medicine
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305
Miller, Christine; Ingmer, Hanne; Thomsen, Line Elnif et al. (2003) DpiA binding to the replication origin of Escherichia coli plasmids and chromosomes destabilizes plasmid inheritance and induces the bacterial SOS response. J Bacteriol 185:6025-31
Xu, Feng-Feng; Gaggero, Carina; Cohen, Stanley N (2002) Polyadenylation can regulate ColE1 type plasmid copy number independently of any effect on RNAI decay by decreasing the interaction of antisense RNAI with its RNAII target. Plasmid 48:49-58
Ingmer, H; Miller, C; Cohen, S N (2001) The RepA protein of plasmid pSC101 controls Escherichia coli cell division through the SOS response. Mol Microbiol 42:519-26
Miller, C; Cohen, S N (1999) Separate roles of Escherichia coli replication proteins in synthesis and partitioning of pSC101 plasmid DNA. J Bacteriol 181:7552-7
Ten Hagen, K G; Ravnan, J B; Cohen, S N (1995) Disparate replication properties of integrated and extrachromosomal forms of bovine papilloma virus in ID13 cells. J Mol Biol 254:119-29
Conley, D L; Cohen, S N (1995) Isolation and characterization of plasmid mutations that enable partitioning of pSC101 replicons lacking the partition (par) locus. J Bacteriol 177:1086-9
Conley, D L; Cohen, S N (1995) Effects of the pSC101 partition (par) locus on in vivo DNA supercoiling near the plasmid replication origin. Nucleic Acids Res 23:701-7
Ravnan, J B; Cohen, S N (1995) Transformed mouse cell lines that consist predominantly of cells maintaining bovine papilloma virus at high copy number. Virology 213:526-34
Ten Hagen, K G; Cohen, S N (1993) Timing of replication of beta satellite repeats of human chromosomes. Nucleic Acids Res 21:2139-42
Miller, C A; Cohen, S N (1993) The partition (par) locus of pSC101 is an enhancer of plasmid incompatibility. Mol Microbiol 9:695-702

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