Elongase gene and production of delta9-polyunsaturated fatty acids

• US 20050089981A1
• Filed: 03/26/2002
• Published: 04/28/2005
• Est. Priority Date: 03/26/2001
• Status: Active Grant

• Current Assignee: University of Bristol
• Original Assignee: University of Bristol
• Inventors: Napier, Johnathan A, Lazarus, Colin m, Lerchl, Jens, Qi, Baoxiu
• Granted Patent: US 7,601,889 B2
• Time in Patent Office: Days
• US Class Current: 435/193
• CPC Class Codes: A01K 2217/05 Animals comprising random inserted nucleic acids (transgenic)
• CPC Class Codes: C12N 15/8247 involving modified lipid metabolism, e.g. seed oil composition
• CPC Class Codes: C12N 9/1029 transferring groups other than amino-acyl groups (2.3.1)

Abstract

This invention relates to a new elongase gene having the sequence SEQ ID NO: 1 or its derivatives, to a gene construct comprising this sequence or its derivatives and to its use. The inventive nucleic acid sequence encodes a polypeptide which elongates α-linolenic acid (C_{18:3 d9, 12, 15}) by at least two carbon atoms whereas γ-linolenic acid (C_{18:3 d6, 9, 12}) is not elongated. The invention additionally relates to vectors or organisms comprising an elongase gene having the sequence SEQ ID NO: 1 or its derivatives.

The invention further relates to a process for the production of polyunsaturated fatty acids (=PUFAs) with an organism which comprises the elongase gene and which organism produces high amounts of oils and especially oils with a high content of unsaturated fatty acids. Additionally the invention relates to an oil and/or fatty acid composition with a higher content of polyunsaturated C₂₀ or C₂₂ fatty acids with at least two double bonds and/or to a triacylglycerol composition with a higher content of said polyunsaturated fatty acids.

Claims

1. An isolated nucleic acid derived from a plant encoding a polypeptide which elongates α

-linolenic acid (C<sub>18;

3 d9, 12, 15</sub>) by at least two carbon atoms whereas γ

-linolenic acid (C<sub>18;

3 d6, 9, 12</sub>) is not elongated.

5. An isolated nucleic acid sequence as claimed in claim 1 or 2, wherein the polypeptide encoded by the sequence elongates Δ

9-fatty acids.

7. A gene construct comprising an isolated nucleic acid having the sequence SEQ ID NO:

1 as claimed in any of claims 1 to 4, wherein the nucleic acid is functionally linked to one or more regulatory signals.

8. A gene construct as claimed in claim 7, comprising additional fatty acid biosynthesis genes.

9. A gene construct as claimed in claim 7 or 8, wherein the additional fatty acid biosynthesis genes are selected from the group consisting of Δ

19-, Δ

17-, Δ

15-, Δ

12-, Δ

9-, Δ

8-, Δ

6-, Δ

5-, Δ

4-desaturases, hydroxylases, elongases, Δ

12-acetylenase, Acyl-ACP-thioesterasen, β

-ketoacyl-ACP-synthases or β

-ketoacyl-ACP-reductases.

10. A vector comprising a nucleic acid as claimed in claim 1 or 2 or a gene construct as claimed in any of the claims 7 to 9.

11. An organism comprising at least one nucleic acid as claimed in claim 1 or 2, a gene construct as claimed in any of claims 7 to 9 or a vector as claimed in claim 10.

12. An organism as claimed in claim 11, wherein the organism is a microorganism, an animal or a plant.

13. An organism as claimed in claim 11 or 12, wherein the organism is a transgenic plant.

14. A process for the production of PUFAs, said process comprising growing an organism which comprises a nucleic acid as claimed in claim 1 or 2, a gene construct as claimed in any of the claims 7 to 9 or a vector as claimed in claim 10 which encodes a polypeptide which elongates α

-linolenic acid (C<sub>18;

3 d9, 12, 15</sub>) by at least two carbon atoms whereas γ

-lino-lenic acid (C<sub>18;

3 d6, 9, 12</sub>) is not elongated, under conditions whereby PUFAs are produced in said organisms.

15. A process as claimed in claim 14, wherein the PUFAs produced by the process are C₂₀ or C₂₂ fatty acid molecules having at least two double bonds in the fatty acid molecule.

16. A process as claimed in claim 14, wherein the C₂₀ or C₂₂ fatty acid molecules are isolated from the organism in the form of an oil, lipid or free fatty acid.

17. A process as claimed in any of claims 14 to 16, wherein the organism is a microorganism, an animal or a plant.

18. A process as claimed in any of claims 14 to 17, wherein the organism is a transgenic plant.

19. A process as claimed in any of the claims 14 to 18, wherein the C₁₈ fatty acid is a fatty acid having three double bonds in the molecule.

20. An oil, lipid or fatty acid or fraction thereof produced by the process as claimed in any of claims 14 to 19.

21. An oil, lipid or fatty acid composition comprising PUFAs and derived from transgenic plants comprising a nucleotide sequence as claimed in claim 1 or 2, a gene construct as claimed in any of claims 7 to 9 or a vector as claimed in claim 10.

22. The use of an oil, lipid or fatty acid composition as claimed in claim 20 or 21, in feed, food, cosmetics or pharmaceuticals.

23. An antibody which specifically interacts with a polypeptide encoded by a nucleotide sequence as claimed in claim 1 or 2.

24. An antisense nucleotide sequence which is complementary to the nucleotide sequence as claimed in claim 1 or 2.

25. A kit comprising a nucleotide sequence as claimed in claim 1 or 2, a gene construct as claimed in any of claims 7 to 9, a vector as claimed in claim 10 or an antibody as claimed in claim 22.

2. An isolated nucleic acid comprising a nucleotide sequence which encodes a polypeptide which elongates α

-linolenic acid (C<sub>18;

3 d9, 12, 15</sub>) by at least two carbon atoms whereas γ

-lino-lenic acid (C<sub>18;

3 d6, 9, 12</sub>) is not elongated, selected from the group consisting of

a) a nucleic acid sequence depicted in SEQ ID NO;

1,

b) a nucleic acid sequence which encodes a polypeptide depicted in SEQ ID NO;

2,

c) derivatives of the sequence depicted in SEQ ID NO;

1, which encodes polypeptides having at least 50 % homology to the sequence encoding amino acid sequences depicted in SEQ ID NO;

2 and which sequences function as an elongase.

3. An isolated nucleic acid sequence as claimed in claim 2, wherein the sequence is derived from a plant.

4. An isolated nucleic acid sequence as claimed in claim 2 or claim 3, wherein the sequence is derived from the genus Isochrysis.

6. An amino acid sequence encoded by an isolated nucleic acid as claimed in any of claims 2 to 4.