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 Δ⁵ desaturase. Saccharomyces cerevisiae expressing the full-length cDNA was able to convert di-homo-γ-linolenic acid to arachidonic acid, thus confirming Δ⁵ desaturation. The 1341 bp Δ⁵ desaturase sequence contained an N-terminal cytochrome b ₅ domain and was located within a kilobase of the C. elegans Δ⁶ 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 Δ⁵ desaturase gene isolated from an animal.