The promoter region associated with the Yarrowia lipolytica ammonium transporter (yat1) gene has been found to be particularly effective for the expression of heterologous genes in oleaginous yeast. The promoter regions of the instant invention have been shown to be advantageously inducible under oleaginous conditions (i.e., nitrogen limitation) and are useful to drive expression of genes involved in the production of ω-3 and ω-6 fatty acids.
