Homologous genetic recombination is a process common to most organisms and is involved in many aspects of DNA metabolism. In addition, the specific introduction of foreign DNA into eukaryotic chromosomes, a basic step in the developing area of gene therapy, is critically dependent on the cell's genetic recombination machinery. For these reasons and others, it is desirable to obtain a detailed understanding of this process. Our long-term goal is to reconstitute homologous recombination in vitro with highly purified proteins, using the bacteriophage T4 as a useful model system. This proposal describes experiments directed towards this goal. We will continue to study a novel four protein strand exchange """"""""machine"""""""" composed of the purified phage uvsX (a RecA-like recombinase), gene 32 (a helixdestabilizing protein), uvsY (an accessory factor) and dda (a DNA helicase) gene products. This is the most biologically relevant system available for the in vitro study of synapsis and branch migration. Indeed, analogues of the latter two factors have not yet been characterized in any other organisms and the T4 studies are providing a wealth of new information on the roles of recombination accessory factors. In addition, we will purify and study as yet uncharacterized proteins that genetic and biochemical studies have implicated as being involved in T4 homologous recombination. With these factors in hand, we hope to be able to reconstitute a complete recombination reaction between completely duplex DNAs in vitro. The interplay between homologous recombination and DNA replication and transcription will also be assessed in vitro. We have been able to reconstitute a replication-dependent homologous pairing reaction and will further develop this novel system. The ability of DNA-binding transcriptional regulatory factors to block protein-mediated branch migrations will be assessed. Finally, we will begin to map specific functions of the uvsX protein to specific domains through the biochemical study of fragments produced proteolytically or genetically. These experiments will initiate an effort to understand this multifunctional protein at a chemical and structural level.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM039393-06
Application #
3296341
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1988-02-01
Project End
1995-01-31
Budget Start
1993-02-01
Budget End
1994-01-31
Support Year
6
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas Austin
Department
Type
Schools of Arts and Sciences
DUNS #
City
Austin
State
TX
Country
United States
Zip Code
78712
Houston, P; Kodadek, T (1994) Spectrophotometric assay for enzyme-mediated unwinding of double-stranded DNA. Proc Natl Acad Sci U S A 91:5471-4
Salinas, F; Kodadek, T (1994) Strand exchange through a DNA-protein complex requires a DNA helicase. Biochem Biophys Res Commun 205:1004-9
Maine, I P; Kodadek, T (1994) Inhibition of the DNA unwinding and ATP hydrolysis activities of the bacteriophage T4 DDA helicase by a sequence specific DNA-protein complex. Biochem Biophys Res Commun 198:1070-7
Maine, I P; Kodadek, T (1994) Efficient unwinding of triplex DNA by a DNA helicase. Biochem Biophys Res Commun 204:1119-24
Jiang, H; Giedroc, D; Kodadek, T (1993) The role of protein-protein interactions in the assembly of the presynaptic filament for T4 homologous recombination. J Biol Chem 268:7904-11
Kodadek, T; Wong, M L (1990) Homologous pairing in vitro initiated by DNA synthesis. Biochem Biophys Res Commun 169:302-9
Kodadek, T (1990) Functional interactions between phage T4 and E. coli DNA-binding proteins during the presynapsis phase of homologous recombination. Biochem Biophys Res Commun 172:804-10
Kodadek, T (1990) The role of the bacteriophage T4 gene 32 protein in homologous pairing. J Biol Chem 265:20966-9