Michaelson LV et al. (1998) FEBS Lett "Functional identification of a fatty acid delta5 desaturase gene from Caenorhabditis elegans."

Stobart AK, Napier JA, Lazarus CM, Michaelson LV, Griffiths G, Lewis MJ

[FEBS Lett, 1998]

We have identified a cDNA from the nematode worm Caenorhabditis elegans that encodes a fatty acid delta5 desaturase. Saccharomyces cerevisiae expressing the full-length cDNA was able to convert di-homo-gamma-linolenic acid to arachidonic acid, thus confirming delta5 desaturation. The 1341 bp delta5 desaturase sequence contained an N-terminal cytochrome b5 domain and was located within a kilobase of the C. elegans delta6 desaturase on chromosome IV. With an amino acid identity of 45% it is possible that one of these genes arose from the other by gene duplication. This is the first example of a delta5 desaturase gene isolated from an animal.

Beaudoin F et al. (2000) Biochem Soc Trans "Production of C20 polyunsaturated fatty acids (PUFAs) by pathway engineering: identification of a PUFA elongase component from Caenorhabditis elegans."

Michaelson LV, Beaudoin F, Napier JA, Sayanova O, Shewry PR, Lewis MJ

[Biochem Soc Trans, 2000]

Using a combination of database-mining and functional characterization, we have identified a component of the polyunsaturated fatty acid (PUFA) elongase. Co-expression of this elongating activity with fatty acid desaturases has allowed us to heterologously reconstitute the PUFA biosynthetic pathway. Both these enzymes (desaturases and elongase components) have undergone gene-duplication events which provide a paradigm for the diverged nature of PUFA biosynthetic activities.

Beaudoin F et al. (2000) Proc Natl Acad Sci U S A "Heterologous reconstitution in yeast of the polyunsaturated fatty acid biosynthetic pathway."

Beaudoin F, Lewis MJ, Shewry PR, Sayanova O, Napier JA, Hey SJ, Michaelson LV

[Proc Natl Acad Sci U S A, 2000]

A Caenorhabditis elegans ORF encoding the presumptive condensing enzyme activity of a fatty acid elongase has been characterized functionally by heterologous expression in yeast. This ORF (F56H11. 4) shows low similarity to Saccharomyces cerevisiae genes involved in fatty acid elongation. The substrate specificity of the C. elegans enzyme indicated a preference for Delta(6)-desaturated C18 polyunsaturated fatty acids. Coexpression of this activity with fatty acid desaturases required for the synthesis of C20 polyunsaturated fatty acids resulted in the accumulation of arachidonic acid from linoleic acid and eicosapentaenoic acid from alpha-linolenic acid. These results demonstrate the reconstitution of the n-3 and n-6 polyunsaturated fatty acid biosynthetic pathways. The C. elegans ORF is likely to interact with endogenous components of a yeast elongation system, with the heterologous nematode condensing enzyme F56H11.4 causing a redirection of enzymatic activity toward polyunsaturated C18 fatty acid substrates.