The promoter regions 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 have been shown to drive high-level expression
of genes involved in the production of .omega.-3 and .omega.-6 fatty
acids.