Molecular characterization of two Brassica napus genes related to oleosins which are highly expressed in the tapetum.

Two highly homologous Brassica napus flower cDNA clones, Sta 41-2 and Sta 41-9, were isolated and characterized. These clones were shown to correspond to genes expressed in the tapetum from the early uninucleate microspore stage to the dinucleate stage. The predicted Sta 41-2 and Sta 41-9 proteins possessed characteristics similar to oleosins such as a polar N-terminal domain, a large relatively conserved hydrophobic domain and a long C-terminal domain which consisted of four different groups of repeats. In addition, like oleosins, the Sta 41-2 and Sta 41-9 proteins have a basic pI, lack a signal peptide and are found in a tissue which accumulates lipids in small lipid bodies.