Article expressing two closely related plant FAD3 genes in yeast cells and found that their enzymes produced significantly different amounts of omega-3 fatty acids and that these differences correlated to differences in rates of protein turnover. The findings indicate that Fad3 protein abundance is regulated by a combination of cis-acting degradation signals and the ubiquitin-proteasome pathway and that modulation of Fad3 protein amounts in response to temperature may represent one mechanism of homeoviscous adaptation in plants.