Methods for nucleic acid manipulation
A method for replicating and amplifying a target nucleic acid sequence is described. A method of the invention involves the formation of a recombination intermediate without the prior denaturing of a nucleic acid duplex through the use of a recombination factor. The recombination intermediate is treated with a high fidelity polymerase to permit the replication and amplification of the target nucleic acid sequence. In preferred embodiments, the polymerase comprises a polymerase holoenzyme. In further preferred embodiments, the recombination factor is bacteriophage T4 UvsX protein or homologs from other species, and the polymerase holoenzyme comprises a polymerase enzyme, a clamp protein and a clamp loader protein, derived from viral, bacteriophage, prokaryotic, archaebacterial, or eukaryotic systems.
1. A method for replicating and amplifying a target nucleic acid sequence comprising:
a) reacting two primers that are complementary to a target nucleic acid sequence within a nucleic acid duplex in the presence of bacteriophage T4 UvsX protein to form a recombination intermediate, without previously denaturing said nucleic acid duplex;
b) admixing a polymerase with said recombination intermediate to form a polymerase complex, whereby the polymerase replicates the target sequence.
2. The method of claim 1 wherein said polymerase is a polymerase holoenzyme.
3. The method of claim 2 wherein said polymerase holoenzyme comprises a polymerase enzyme, a clamp protein, and a clamp loader protein.
4. The method of claim 3 wherein said polymerase enzyme, said clamp protein and said clamp loader are obtained from bacteriophage T4.
5. The method of claim 4 wherein said polymerase is bacteriophage T4 gene product 43 polymerase, said clamp protein is bacteriophage T4 gene product 45 clamp protein and said clamp loader is bacteriophage T4 gene product 44/gene product 62 clamp loader complex.
6. The method of claim 2 wherein said polymerase holoenzyme complex comprises a viral, bacteriophage, eukaryote archeabacteria, or prokaryote polymerase holoenzyme complex.
7. The method of claim 6 wherein said bacteriophage is T4 bacteriophage T4, and said polymerase holoenzyme complex includes a bacteriophage T4 gene product 43 polymerase.
8. The method of claim 6 wherein said bacteriophage is bacteriophage T4, and said polymerase holoenzyme complex includes a bacteriophage T4 gene product 45 clamp protein.
9. The method of claim 6 wherein said prokaryote is E. coli and said polymerase holoenzyme complex includes DAN polymerase III holoenzyme.
10. The method of claim 6 wherein said eukaryote is yeast and said polymerase holoenzyme complex includes DNA polymerase delta.
11. The method of claim 6 wherein said eukaryote is yeast and said polymerase holoenzyme complex includes DNA polymerase epsilon.
12. The method of claim 1 wherein a single stranded binding protein is used to facilitate downstream strand displacement synthesis by said polymerase.
13. The method of claim 12 wherein said single stranded binding protein is bacteriophage T4 gene product 32.
14. The method of claim 1 wherein a single stranded binding protein is used to destabilize the helix at or near the points of the primer template junctions.