Methods and compositions for synthesis of long chain polyunsaturated fatty acids

A method for production of stearidonic acid in a yeast culture, said method comprising:

• growing a yeast culture having a plurality of recombinant yeast cells, wherein said yeast cells or an ancestor of said yeast cells were transformed with a vector comprising Mortierella alpina DNA encoding a .DELTA.6 desaturase polypeptide which converts .alpha.-linolenic acid to stearidonic acid, wherein said DNA is operably associated with an expression control sequence functional in said yeast cells, under conditions whereby said DNA is expressed, whereby stearidonic acid is produced from .alpha.-linolenic acid in said yeast culture.

A method for production of linoleic acid in a yeast culture, said method comprising:

• growing a yeast culture having a plurality of recombinant yeast cells, wherein said yeast cells or an ancestor of said yeast cells were transformed with a vector comprising Mortierella alpina DNA encoding a .DELTA.12 desaturase polypeptide which converts oleic acid to linoleic acid, wherein said DNA is operably associated with an expression control sequence functional in said yeast cells, under conditions whereby said DNA is expressed, whereby linoleic acid is produced oleic acid in said yeast culture.

A method for production of stearidonic acid in a eukaryotic cell culture, said method comprising:

• growing a eukaryotic cell culture having a plurality of recombinant eukaryotic cells, wherein said recombinant eukaryotic cells or ancestors of said recombinant eukaryotic cells were transformed with a vector comprising Mortierella alpina DNA encoding a polypeptide which converts .alpha.-linolenic to stearidonic acid, wherein said DNA is operably associated with an expression control sequence functional in said recombinant eukaryotic cells, under conditions whereby said DNA is expressed, whereby stearidonic acid is produced from .alpha.-linolenic in said eukaryotic cell culture.

A method for production of linoleic acid in a eukaryotic cell culture, said method comprising:

• growing a eukaryotic cell culture having a plurality of recombinant eukaryotic cells, wherein said recombinant eukaryotic cells or ancestors of said recombinant eukaryotic cells were transformed with a vector comprising Mortierella alpina DNA encoding a polypeptide which converts oleic acid to linoleic acid, wherein said DNA is operably associated with an expression control sequence functional in said recombinant eukaryotic cells, under conditions whereby said DNA is expressed, whereby linoleic acid is produced from oleic acid in said eukaryotic cell culture.

A method of making .alpha.-linolenic acid, said method comprising:

• growing a recombinant yeast cell comprising a nucleotide sequence which encodes a functionally active .DELTA.6 desaturase having the amino acid sequence depicted in SEQ ID NO:2, and at least one nucleic acid construct comprising a nucleotide sequence which encodes a functionally active .DELTA.12 desaturase 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 under conditions whereby said nucleotide sequences are expressed, whereby .gamma.-linolenic acid is produced in said yeast cell.