Identification and characterization of an animal Delta(12) fatty acid desaturase gene by heterologous expression in Saccharomyces cerevisiae

We have cloned a Caenorhabditis elegans cDNA encoding a Delta 12 fatty acid desaturase and demonstrated its activity by heterologous expression in Sac charomyces cerevisiae. The predicted protein is highly homologous both to t he cloned plant genes with similar function and to the published sequence o f the C. elegans omega-3 fatty acid desaturase. In addition, it conforms to the structural constraints expected of a membrane-bound fatty acid desatur ase including the canonical histidine-rich regions. This is the first repor t of a cloned animal Delta(12) desaturase gene. Expression of this cDNA in yeast resulted in the accumulation of 16:2 and 18:2 (linoleic) acids. The i ncrease of membrane fluidity brought about by this change in unsaturation w as measured. The production of polyunsaturated fatty acids in yeast cells a nd the concomitant increase in membrane fluidity was correlated with a mode st increase in growth rate at low temperature and with increased resistance to ethanol and oxidative stress. (C) 2000 Academic Press.