Methods and compositions for synthesis of long chain poly-unsaturated fatty acids

An isolated nucleic acid encoding a polypeptide having an amino acid sequence depicted in SEQ ID NO:

• 2 or SEQ ID NO:
• 4.

An isolated nucleic acid comprising the nucleotide sequence depicted in a SEQ ID NO:

• 1 or SEQ ID NO:3.

A nucleic acid fragment consisting of:

• at least 50 contiguous nucleotides of the sequences depicted in SEQ ID NO:
• 1 or SEQ ID NO:
• 3 or their complementary sequences.

A nucleic acid construct comprising the nucleotide sequence depicted in SEQ ID NO:

• 1 or SEQ ID NO:
• 3 linked to a heterologous nucleic acid.

A nucleic acid construct comprising a nucleotide sequence which encodes a polypeptide comprising an amino acid sequence depicted in SEQ ID NO:

• 2 or SEQ ID NO:
• 4.

A nucleic acid construct comprising a fungal nucleotide sequence which encodes a functionally active protein having desaturase activity that desaturates a fatty acid molecule at carbon 12 said protein having an amino acid sequence depicted in a SEQ ID NO:

• 4.

A recombinant yeast cell comprising at least one copy of a vector comprising a Mortierella alpina nucleotide sequence which encodes a polypeptide having desaturase activity that desaturates a fatty acid molecule at carbon 6 or 12 wherein said yeast cell or an ancestor of said yeast cell was transformed with said vector to produce said recombinant yeast cell, and wherein said nucleotide sequence is operably associated with an expression control sequence functional in said recombinant yeast cell.

A host cell comprising a vector which includes a nucleic acid which encodes a fatty acid desaturase derived from Mortierella alpina, wherein said desaturase has an amino acid sequence represented by SEQ ID NO:

• 2 or SEQ ID NO:
• 4, and wherein said nucleic acid is operably linked to a promoter.

An isolated nucleic acid from Mortierella alpina encoding a polypeptide having desaturase activity that desaturates a fatty acid molecule at carbon 6 or 12.

A recombinant yeast cell comprising at least one nucleic acid construct comprising a nucleotide sequence which encodes a functionally active protein having desaturase activity that desaturates a fatty acid molecule at carbon 6, said protein having an amino acid sequence depicted in SEQ ID NO:

• 2, and at least one nucleic acid construct comprising a nucleic acid sequence which encodes a functionally active protein having desaturase activity that desaturates a fatty acid molecule at carbon 12, said protein having an amino acid sequence depicted in SEQ ID NO:
• 4, wherein said nucleic acid constructs are operably associated with transcription control sequences functional in a yeast cell.