Functional identification of a fatty acid Δ5 desaturase gene from Caenorhabditis elegans

Abstract We have identified a cDNA from the nematode worm Caenorhabditis elegans that encodes a fatty acid Δ 5 desaturase. Saccharomyces cerevisiae expressing the full-length cDNA was able to convert di-homo-γ-linolenic acid to arachidonic acid, thus confirming Δ 5 desaturation. The 1341 bp Δ 5 desaturase sequence contained an N-terminal cytochrome b 5 domain and was located within a kilobase of the C. elegans Δ 6 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 Δ 5 desaturase gene isolated from an animal.