Omega-3 fatty acid desaturase

• US 20020042933A1
• Filed: 12/20/2000
• Published: 04/11/2002
• Est. Priority Date: 02/18/1997
• Status: Abandoned Application

• Current Assignee: Washington State University
• Original Assignee: Washington State University
• Inventors: Browse, John A., Spychalla, James P.
• Application Number:
  US09/747,755
• Publication Number:
  US 20020042933A1
• Time in Patent Office: Days
• US Class Current: 800/298
• CPC Class Codes: C12N 15/8247 involving modified lipid metabolism, e.g. seed oil composition
• CPC Class Codes: C12N 9/0014 acting on the CH-NH2 group of donors (1.4)
• CPC Class Codes: C12N 9/0083 Miscellaneous (1.14.99)

Abstract

Recombinant expression of fat-1 gene of Caenorhabditis elegans in a wide variety of cells, including cells of Arabidopsis thaliana and Saccharomyces cerevisiae, produces a polypeptide having ω-3 desaturase activity.

Claims

1. A cell comprising a recombinant FAT-1 polypeptide that desaturates an ω

-6 fatty acid to a corresponding ω

-3 fatty acid.

2. The cell of claim 1 wherein the ω

-6 fatty acid has a carbon chain of at least 18 carbons.

3. The cell of claim 2 wherein the ω

-6 fatty acid is a 20-carbon ω

-6 fatty acid or a 22-carbon ω

-6 fatty acid.

4. The cell of claim 1 wherein the ω

-6 fatty acid has a double bond at one or more positions selected from the group consisting of Δ

4, Δ

5, Δ

6, Δ

7, and Δ

8.

5. The cell of claim 1 having a proportion of ω

-3 fatty acids that is at least 10% greater than an otherwise similar cell lacking the recombinant FAT-1 polypeptide.

6. The cell of claim 5 having a proportion of ω

-3 fatty acids that is at least 20% greater than an otherwise similar cell lacking the recombinant FAT-1 polypeptide.

7. The cell of claim 6 having a proportion of ω

-3 fatty acids that is at least 50% greater than an otherwise similar cell lacking the recombinant FAT-1 polypeptide.

8. The cell of claim 1 wherein the ω

-6 fatty acid has a carbon chain of at least 20 carbons and at least 25% of the ω

-6 fatty acid is desaturated to the corresponding ω

-3 fatty acid.

9. The cell of claim 1 wherein the recombinant FAT-1 polypeptide has at least 60% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

10. The cell of claim 1 wherein the recombinant FAT-1 polypeptide has at least 70% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

11. The cell of claim 10 wherein the recombinant FAT-1 polypeptide has at least 80% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

12. The cell of claim 10 wherein the recombinant FAT-1 polypeptide has at least 90% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

13. The cell of claim 1 wherein the recombinant FAT-1 polypeptide has only conservative amino acid substitutions to the FAT-1 polypeptide of SEQ ID NO:

1.

14. The cell of claim 1 wherein the recombinant FAT-1 polypeptide has 100% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

15. The cell of claim 1 wherein the recombinant FAT-1 polypeptide is encoded by a polynucleotide that comprises a sequence having at least 70%s nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

16. The cell of claim 15 wherein the polynucleotide comprises a sequence having at least 80% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

17. The cell of claim 15 wherein the polynucleotide comprises a sequence having at least 90% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

18. The cell of claim 15 wherein the polynucleotide comprises a sequence having 100% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

19. The cell of claim 1 wherein the polypeptide is encoded by a polynucleotide comprising a full-length native fat-1 protein-coding region.

20. A cell of claim 1 of an organism selected from the group consisting of a bacterium, a cyanobacterium, a phytoplankton, an alga, a fungus, a plant, and an animal.

21. A lipid from the cell of claim 1.

22. The lipid of claim 21 wherein at least 25% of an ω

-6 fatty acid of the cell having a carbon chain of at least 20 carbons has been converted to a corresponding ω

-3 fatty acid by the FAT-1 polypeptide.

24. The transgenic plant of claim 23 wherein the fat-1 polynucleotide is expressible in a seed of the plant.

25. A seed of the transgenic plant of claim 23.

26. A lipid from the transgenic plant of claim 23 that has a higher proportion of ω

-3 fatty acids than a control lipid obtained from an otherwise similar plant lacking the fat-1 polynucleotide.

28. The method of claim 27 wherein the ω

-6 fatty acid is an ω

-6 fatty acid having a carbon chain of at least 18 carbons.

29. The method of claim 28 wherein the ω

-6 fatty acid is a 20-carbon ω

-6 fatty acid or a 22-carbon ω

-6 fatty acid.

30. The method of claim 27 wherein the ω

-6 fatty acid comprises a double bond at one or more positions selected from the group consisting of Δ

4, Δ

5, Δ

6, Δ

7, and Δ

8.

31. The method of claim 27 wherein the recombinant polypeptide has at least 60% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

32. The method of claim 27 wherein the recombinant polypeptide has at least 70% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

33. The method of claim 32 wherein the recombinant polypeptide has at least 80% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

34. The method of claim 32 wherein the recombinant polypeptide has at least 90% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

35. The method of claim 32 wherein the recombinant polypeptide has only conservative amino acid substitutions to the FAT-1 polypeptide of SEQ ID NO:

1.

36. The method of claim 32 wherein the recombinant polypeptide has 100% amino acid sequence identity with the FAT-1 polypeptide of SEQ ID NO:

1.

37. The method of claim 27 wherein the FAT-1 polypeptide is encoded by a recombinant polynucleotide that comprises a sequence having at least 70% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

38. The method of claim 37 wherein the polynucleotide comprises a sequence having at least 80% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

39. The method of claim 37 wherein the polynucleotide comprises a sequence having at least 90% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

40. The method of claim 37 wherein the polynucleotide comprises a sequence having 100% nucleotide sequence identity with the fat-1 polynucleotide sequence of SEQ ID NO:

1.

41. The method of claim 27 wherein the polypeptide is encoded by a polynucleotide that comprises a full-length native fat-1 protein-coding region.

42. A method of claim 27 wherein the cell is a cell of an organism selected from the group consisting of a bacterium, a cyanobacterium, a phytoplankton, an alga, a fungus, a plant, and an animal.

43. The method of claim 42 wherein the cell is a plant cell.

44. The method of claim 42 wherein the cell is a yeast cell.

46. The method of claim 45 wherein the lipid comprises an ω

-6 fatty acid having a carbon chain of at least 20 carbons, the method comprising desaturating at least 25% of the ω

-6 fatty acid to the corresponding ω

-3 fatty acid.

47. The method of claim 45 comprising the step of expressing a recombinant fat-1 polynucleotide in a cell comprising the lipid, thereby producing the recombinant FAT-1 polypeptide in the cell.

23. A transgenic plant comprising a fat-1 polynucleotide that is expressible in at least a part of the plant.

27. A method of desaturating an ω

-6 fatty acid to a corresponding ω

-3 fatty acid comprising the steps of;

(a) providing a cell that comprises a recombinant FAT-1 polypeptide; and

(b) growing the cell under conditions under which the FAT-1 polypeptide desaturates an ω

-6 fatty acid to produce a corresponding ω

-3 fatty acid.

45. A method of producing a lipid comprising an ω

-3 fatty acid comprising the steps of;

(a) providing a lipid that comprises an ω

-6 fatty acid; and

(b) desaturating at least some of the ω

-6 fatty acid to a corresponding ω

-3 fatty acid with a recombinant FAT-1 polypeptide.