System for capturing and modifying large pieces of genomic DNA and constructing organisms with chloroplasts
View Patent ↗The functional analysis of genes frequently requires the manipulation of large genomic regions. A yeast-bacteria shuttle vector is described that can be used to clone large regions of DNA by homologous recombination. Also described is a method for isolating entire genomes, including chloroplast genomes, or large portions thereof, and manipulating the same. Also described are methods for determining minimal genomes, minimal pathway requirements, and minimal organelle genomes.
1. A plurality of vectors for assembling a circular chloroplast genome, comprising
a plurality of vectors, each comprising at least 20 kb of chloroplast DNA, and collectively comprising all chloroplast genes necessary to carry out photosynthesis;
wherein each vector in said plurality of vectors comprises two regions for homologous recombination with one or two other vectors in said plurality of vectors,
wherein at least one vector of said plurality of vectors comprises a yeast DNA replication element and at least one vector of said plurality of vectors comprises a bacterial DNA replication element, wherein said vectors comprising said yeast and bacterial DNA replication elements can be the same or different, and
wherein at least one vector of said plurality of vectors comprises a yeast stability element comprising at least one yeast selection marker and said at least one vector comprising a stability element does not contain a yeast DNA replication element.
2. The plurality of vectors of claim 1 , wherein said plurality of vectors comprises two vectors and each of said vectors comprise two areas for homologous recombination with each other.
3. The plurality of vectors of claim 1 , wherein said yeast DNA replication element is a yeast centromere, a yeast autonomous replicating sequence, or both.
4. The plurality of vectors of claim 1 , wherein said bacterial DNA replication element is a P1 replication sequence or an F factor replication sequence.
5. The plurality of vectors of claim 1 , wherein at least one of said plurality of vectors comprises a single yeast DNA replication element.
6. The plurality of vectors of claim 5 , wherein said yeast DNA replication element and said bacterial DNA replication element are contained in the same vector.
7. The plurality of vectors of claim 1 , wherein said the chloroplast DNA when assembled into a circular chloroplast genome contains at least 140 kb of DNA.
8. The plurality of vectors of claim 1 , wherein at least one of said vectors comprises chemically synthesized DNA.
9. The plurality of vectors of claim 1 , wherein at least one of said vectors comprises genomic chloroplast DNA from a photosynthetic organism.
10. The plurality of vectors of claim 9 , wherein said genomic chloroplast DNA from a photosynthetic organism comprises at least one modification.
11. The plurality of vectors of claim 10 , wherein said at least one modification is insertion of a heterologous or homologous polynucleotide, deletion of one or more nucleic acid bases, insertion of one or more nucleic acid bases, mutation of one or more nucleic acid bases, rearrangement of one or more polynucleotides, or any combination thereof.
12. The plurality of vectors of claim 1 , wherein said yeast stability element comprises a pair of yeast selection markers.
13. The plurality of vectors of claim 12 , wherein said pair of yeast selection markers is a URA3 gene and an additional yeast selection marker.
14. The plurality of vectors of claim 13 , wherein said additional yeast selection marker is an ADE gene, a LEU gene, a HIS gene, a LYS gene or a G418 gene.
15. The plurality of vectors of claim 12 , wherein for each vector comprising a yeast stability element, said yeast stability element comprises a different pair of yeast selection markers.
16. A fungal or bacterial host organism comprising the plurality of vectors of claim 1 .
17. A method of assembling a circular chloroplast genome, comprising
obtaining a plurality of vectors, each vector comprising at least 20 kb of chloroplast DNA, and collectively comprising all chloroplast genes necessary to carry out photosynthesis;
wherein each vector in said plurality of vectors comprises two regions for homologous recombination with one or two other vectors in said plurality of vectors,
wherein at least one vector of said plurality of vectors comprises a yeast DNA replication element and at least one vector of said plurality of vectors comprises a bacterial DNA replication element, wherein said vectors comprising said yeast and bacterial DNA replication elements can be the same or different, and
wherein at least one vector of said plurality of vectors comprises a yeast stability element comprising at least one yeast selection marker and said at least one vector comprising a stability element does not contain a yeast DNA replication element;
introducing said plurality of vectors into yeast to assemble said plurality of vectors by homologous recombination to produce an assembled circular chloroplast genome; and
selecting for complete assembly of said circular chloroplast genome by selecting for the presence of said at least one stability element.
18. The method of claim 17 , wherein said plurality of vectors comprises two vectors and each of said vectors comprise two areas for homologous recombination with each other.
19. The method of claim 17 , wherein said yeast DNA replication element is a yeast centromere, a yeast autonomous replicating sequence, or both.
20. The method of claim 17 , wherein said bacterial DNA replication element is a P1 replication sequence or an F factor replication sequence.
21. The method of claim 17 , wherein at least one of said plurality of vectors comprises a single yeast DNA replication element.
22. The method of claim 17 , wherein said yeast DNA replication element and said bacterial DNA replication element are contained in the same vector.
23. The method of claim 17 , wherein said chloroplast DNA when assembled into a circular chloroplast genome contains at least 140 kb of DNA.
24. The method of claim 17 , where at least one of said vectors comprises chemically synthesized DNA.
25. The method of claim 17 , wherein at least one of said vectors comprises genomic chloroplast DNA from a photosynthetic organism.
26. The method of claim 25 , wherein said photosynthetic organism is an alga.
27. The method of claim 25 , wherein said genomic chloroplast DNA from a photosynthetic organism comprises at least one modification.
28. The method of claim 27 , wherein said at least one modification is insertion of a heterologous or homologous polynucleotide, deletion of one or more nucleic acid bases, insertion of one or more nucleic acid bases, mutation of one or more nucleic acid bases, rearrangement of one or more polynucleotides, or any combination thereof.
29. The method of claim 17 , wherein said yeast stability element comprises a pair of yeast selection markers.
30. The method of claim 29 , wherein said pair of yeast selection markers is a URA3 gene and an additional yeast selection marker.
31. The method of claim 30 , wherein said additional yeast selection marker is an ADE gene, a LEU gene, a HIS gene, a LYS gene or a G418 gene.
32. The method of claim 29 , wherein for each vector comprising a yeast stability element, said yeast stability element comprises a different pair of yeast selection markers.
33. The method of claim 17 , further comprising introducing said assembled circular chloroplast genome into an algal, plant, or cyanobacteria host organism.
34. The method of claim 17 , further comprising removing said at least one stability element following selection for complete assembly of said circular chloroplast genome.