E. coli recA protein in vitro promotes homologous pairing of single-stranded or partially single-stranded DNA in three sequential steps: 1) presynaptic polymerization of recA protein on single-stranded DNA, 2) synapsis, the conjunction and homologous alignment of DNA molecules, and 3) strand exchange. Three nucleoprotein structures have been identified as putative intermediates: 1) presynaptic complexes, single-stranded DNA with recA protein polymerized on it, 2) conjoined molecules, double-stranded DNA bound to presynaptic complexes without homologous pairing, and 3) synaptic or nascent heteroduplex structures, novel three-stranded intermediates in which the incoming strand is not topologically interwound with its complement but is nonetheless base-paired via a nascent heteroduplex joint. By enzymological and biochemical methods, we will explore the structures of these intermediates, aiming specifically at defining the points of contact of the strands of DNA and recA protein. We have studied the interactions of reCA protein with the following enzymes from E. coli: single-strand binding protein, T4 gene 32 protein, topoisomerase I, DNA ligase, recBC DNase, exonuclease I and Lambda exonuclease. By a series of model systems involving various DNA substrates and various combinations of enzymens we propose to develop recombination assays that are suitable for use with crude extracts or fractions thereof in order to reconstitute recombination in vitro and thereby to enable the identification of all of the enzymens of the major pathway of homologous recombination in E. coli. For this purpose, recA protein provides an instrumental reagent, since it both brings DNA molecules together and puts them in homologous alignment. On the one hand no single pathway of recombination has yet been elucidated; on the other hand, research made possible in recent years by recombinant DNA methodology has revealed the importance of recombination not only in inheritance but also in biological regulation and development.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM033504-03
Application #
3283294
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1984-05-01
Project End
1989-04-30
Budget Start
1986-05-01
Budget End
1987-04-30
Support Year
3
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Yale University
Department
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Noirot, Philippe; Gupta, Ravindra C; Radding, Charles M et al. (2003) Hallmarks of homology recognition by RecA-like recombinases are exhibited by the unrelated Escherichia coli RecT protein. EMBO J 22:324-34
Passy, S I; Yu, X; Li, Z et al. (1999) Rings and filaments of beta protein from bacteriophage lambda suggest a superfamily of recombination proteins. Proc Natl Acad Sci U S A 96:4279-84
Chiu, S K; Low, K B; Yuan, A et al. (1997) Resolution of an early RecA-recombination intermediate by a junction-specific endonuclease. Proc Natl Acad Sci U S A 94:6079-83
Plug, A W; Xu, J; Reddy, G et al. (1996) Presynaptic association of Rad51 protein with selected sites in meiotic chromatin. Proc Natl Acad Sci U S A 93:5920-4
Kurumizaka, H; Aihara, H; Ikawa, S et al. (1996) A possible role of the C-terminal domain of the RecA protein. A gateway model for double-stranded DNA binding. J Biol Chem 271:33515-24
Reddy, G; Burnett, B; Radding, C M (1995) Uptake and processing of duplex DNA by RecA nucleoprotein filaments: insights provided by a mixed population of dynamic and static intermediates. Biochemistry 34:10194-204
Rao, B J; Radding, C M (1995) RecA protein mediates homologous recognition via non-Watson-Crick bonds in base triplets. Philos Trans R Soc Lond B Biol Sci 347:5-12
Ashley, T; Plug, A W; Xu, J et al. (1995) Dynamic changes in Rad51 distribution on chromatin during meiosis in male and female vertebrates. Chromosoma 104:19-28
Rao, B J; Chiu, S K; Bazemore, L R et al. (1995) How specific is the first recognition step of homologous recombination? Trends Biochem Sci 20:109-13
Haaf, T; Golub, E I; Reddy, G et al. (1995) Nuclear foci of mammalian Rad51 recombination protein in somatic cells after DNA damage and its localization in synaptonemal complexes. Proc Natl Acad Sci U S A 92:2298-302

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