The regulatory sequences associated with the Yarrowia lipolytica glyceraldehyde-3-phosphate dehydrogenase (gpd) and phosphoglycerate mutase (gpm) genes have been found to be particularly effective for the expression of heterologous genes in oleaginous yeast. The promoter regions of the invention, intron and enhancer have been shown to drive high-level expression of genes involved in the production of .omega.-3 and .omega.-6 fatty acids.