This proposal is a request for continuation of support of our research on the molecular nature and replication of extrachromosomal elements (plasmids) in bacteria using a number of physical, biochemical, and genetic methods. In previous work we have established a detailed physical map of the transmissible drug resistance (R) plasmid NR1 and localized the genes and functions required for autonomous replication to a 2.2 kilobase segment. For stable inheritance, however, plasmid derivatives require another function (stb) which must be present in cis, suggesting that it plays a structural role in partitioning plasmid molecules at cell division.
The specific aims of our research plan concern four aspects of the organization and control of the expression of the replication genes and functions of the R plasmid NR1. (i) The functional role of RNA transcripts from the replication region; (ii) The control of the expression of replication genes and the role of corresponding gene products in plasmid replication; (iii) The mechanism of plasmid copy number control, incompatibility, and the initiation of replication at the origin; (iv) The mechanism by which the stb locus mediates stable plasmid inheritance. This research will contribute in a fundamental way to our understanding of the structure, function, and replication of R plasmids which will be of importance in combatting the spread of multiple drug resistance in bacteria. An understanding of the mechanism of DNA replication and its control will not only be an important advance in its own right, but also will be of fundamental importance in the understanding of cell growth and development. R plasmid replication and drug resistance gene amplification are especially relevant to these phenomena, since the components of R plasmids are controlled by a variety of regulatory mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM030731-07
Application #
3278562
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1981-09-01
Project End
1992-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
7
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
School of Medicine & Dentistry
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Jiang, T; Min, Y N; Liu, W et al. (1993) Insertion and deletion mutations in the repA4 region of the IncFII plasmid NR1 cause unstable inheritance. J Bacteriol 175:5350-8
Wu, R; Wang, X; Womble, D D et al. (1993) Suppression of replication-deficient mutants of IncFII plasmid NR1 can occur by two different mechanisms that increase expression of the repA1 gene. J Bacteriol 175:3161-73
Wu, R; Wang, X; Womble, D D et al. (1992) Expression of the repA1 gene of IncFII plasmid NR1 is translationally coupled to expression of an overlapping leader peptide. J Bacteriol 174:7620-8
Tabuchi, A; Min, Y N; Womble, D D et al. (1992) Autoregulation of the stability operon of IncFII plasmid NR1. J Bacteriol 174:7629-34
Min, Y N; Tabuchi, A; Womble, D D et al. (1991) Transcription of the stability operon of IncFII plasmid NR1. J Bacteriol 173:2378-84
Tang, X B; Womble, D D; Rownd, R H (1989) DnaA protein is not essential for replication of IncFII plasmid NR1. J Bacteriol 171:5290-5
Dong, X N; Rouillard, K P; Womble, D D et al. (1989) DNA bending near the replication origin of IncFII plasmid NR1. J Bacteriol 171:703-7
Tabuchi, A; Min, Y N; Kim, C K et al. (1988) Genetic organization and nucleotide sequence of the stability locus of IncFII plasmid NR1. J Mol Biol 202:511-25
Dong, X N; Womble, D D; Rownd, R H (1988) In-vivo studies on the cis-acting replication initiator protein of IncFII plasmid NR1. J Mol Biol 202:495-509
Min, Y N; Tabuchi, A; Fan, Y L et al. (1988) Complementation of mutants of the stability locus of IncFII plasmid NR1. Essential functions of the trans-acting stbA and stbB gene products. J Mol Biol 204:345-56

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