Methods and means for producing efficient silencing construct using recombinational cloning

• US 20050160490A1
• Filed: 01/12/2005
• Published: 07/21/2005
• Est. Priority Date: 01/26/2001
• Status: Active Grant

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Helliwell, Christopher A., Waterhouse, Peter M., Wesley, Susan V.
• Granted Patent: US 7,846,718 B2
• Time in Patent Office: Days
• US Class Current: 800/278
• CPC Class Codes: C12N 15/10 Processes for the isolation, preparation or purification of DNA or RNA chemical preparation of DNA or RNA C07H21/00; preparation of non-structural polynucleotides from microorganisms or with enzymes C12P19/34
• CPC Class Codes: C12N 15/63 Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
• CPC Class Codes: C12N 15/8218 Antisense, co-suppression, viral induced gene silencing [VIGS], post-transcriptional induced gene silencing [PTGS]
• CPC Class Codes: C12N 15/8249 involving ethylene biosynthesis, senescence or fruit development, e.g. modified tomato ripening, cut flower shelf-life
• CPC Class Codes: C12N 15/825 involving pigment biosynthesis
• CPC Class Codes: C12N 15/827 Flower development or morphology, e.g. flowering promoting factor [FPF]

Abstract

Methods and means are provided for producing chimeric nucleic acid constructs capable of producing dsRNA for silencing target nucleic acid sequences of interest using recombinational cloning.

Claims

1. (canceled)

7-10. -10. (canceled)

13-17. -17. (canceled)

18. A vector comprising the following operably linked DNA fragments:

an origin of replication (1) allowing replication in a recipient cell,

a selectable marker region (2) capable of being expressed in said recipient cell; and

a chimeric DNA construct comprising in sequence;

a promoter or promoter region (3) capable of being recognized by a prokaryotic RNA polymerase;

a first recombination site (4), a second recombination site (5), a third recombination site (6) and a fourth recombination site (7);

a 3′

transcription terminating and polyadenylation region (8) functional in said eukaryotic cell;

wherein

said first recombination site (4) and said fourth recombination site (7) are capable of reacting with a same recombination site, and said second recombination site (5) and said third recombination site (6), are capable of reacting with a same recombination site;

and wherein

said first recombination site (4) and said second recombination site (5) do not recombine with each other or with a same recombination site;

or

said third recombination site (6) and said fourth recombination site (7) do not recombine with each other or with a same recombination site.

2. The vector of claim 18, wherein said first (4) and second (5) recombination site flank a second selectable marker gene (10) and said third (6) and fourth (7) recombination site flank a third selectable marker gene (9).

3. The vector of claim 18, wherein said chimeric DNA construct comprises a region flanked by intron processing signals (11), functional in said eukaryotic cell, located between said second recombination site (5) and said third recombination site (6).

4. The vector of claim 3, wherein said region flanked by intron processing signals is an intron sequence functional in said eukaryotic cell.

5. The vector of claim 3, further comprising a fourth selectable marker gene (19), located between said second (5) and third (6) recombination site.

6. The vector of claim 18, wherein said vector comprises a selectable marker gene selected from the group consisting of an antibiotic resistance gene, a tRNA gene, an auxotrophic marker, a toxic gene, a phenotypic marker, an antisense oligonucleotide;

a restriction endonuclease;

a restriction endonuclease cleavage site, an enzyme cleavage site, a protein binding site, an a sequence complementary PCR primer.

11. The vector of claim 18, wherein said first (4) and fourth (7) recombination site is attR1 comprising the nucleotide sequence of SEQ ID No 4 and said second (5) and third (6) recombination site is attR2 comprising the nucleotide sequence of SEQ ID No 5.

12. The vector of claim 18, wherein said first (4) and fourth (7) recombination site is attP1 comprising the nucleotide sequence of SEQ ID No 10 and said second (5) and third (6) recombination site is attP2 comprising the nucleotide sequence of SEQ ID No 11.

19. The vector of claim 18, wherein said RNA polymerase is a bacteriophage single subunit RNA polymerase.

20. A kit comprising the vector of claim 18.

21. The kit of claim 20, further comprising at least one recombination protein capable of recombining a DNA segment comprising at least one of said recombination sites.

22. A method for making a chimeric DNA construct capable of expressing a dsRNA in a eukaryotic cell comprising the steps of combining in vitro:

a vector according to claim 18;

an insert DNA comprising a DNA segment of interest (12) flanked by a fifth recombination site (13) which is capable of recombining with said first (4) or fourth (7) recombination site on said vector; and

a sixth recombination site (14) which is capable of recombining with said second (5) or third (6) recombination site on said vector;

at least one site specific recombination protein capable of recombining said first (4) or fourth (7) and said fifth (13) recombination site and said second (5) or third (6) and said sixth (14) recombination site;

allowing recombination to occur so as to produce a reaction mixture comprising product DNA molecules, said product DNA molecules comprising in sequence;

said promoter or promoter region (3) capable of being recognized by RNA polymerases of said eukaryotic cell;

a recombination site (15) which is the recombination product of said first (4) and said fifth (13) recombination site;

said DNA fragment of interest (12);

a recombination site (16) which is the recombination product of said second (4) and said sixth (14) recombination site;

a recombination site (17) which is the recombination product of said third (5) and said sixth (14) recombination site;

said DNA fragment of interest (12) in opposite orientation;

a recombination site (18) which is the recombination product of said fourth (7) and said fifth (13) recombination site; and

said 3′

transcription terminating and polyadenylation region (8) functional in said eukaryotic cell; and

selecting said product DNA molecules.

24. The method according to claim 22, wherein said insert DNA is a linear DNA molecule.

25. The method according to claim 22, wherein said insert DNA is a circular DNA molecule.

26. The method according to claim 22, wherein said at least one recombination protein is selected from (i) Int (λ

integrase) and IHF (integration host factor) and (ii) Int, Xis (λ

excisionase), and IHF.

27. The method according to claim 22, wherein multiple insert DNAs comprising different DNA fragments of interest are processed simultaneously.

34. A vector according to claim 18, wherein the origin of replication allows replication in bacteria.

35. A vector according to claim 34, wherein the bacteria is Escherichia coli.

36. A vector according to claim 18, wherein said first recombination site (4) and said fourth recombination site (7) are identical.

37. A vector according to claim 18, wherein said second recombination site (5) and said third recombination site (6) are identical.

38. A prokaryotic host comprising the vector according to claim 18.

39. Feed for an animal comprising the prokaryotic host of claim 38.

40. The feed for an animal of claim 39, wherein said animal is a nematode.

23. (canceled)

28-33. -33. (canceled)