High expression of unsaturated fatty acid synthesis gene OLE1 in sake yeasts

GeneFilters((R)) and Northern blot analysis revealed that the sake yeast strain Kyokai no. 7 (K7) showed a higher expression level of OLE1, which encodes a Delta-9 fatty acid desaturase gene, compared with the laboratory yeast strain X2180-1A. Other sake yeasts also showed a high expression level of OLE1. Unsaturated fatty acid concentrations in strain K7 are higher than that in strain X2180-1A, suggesting that the higher expression level of OLE1 in sake yeasts increases the unsaturated fatty acid content in the cell membrane. Experiments using OLE1 promoter:lacZ fusion reporter genes revealed that both the cis element of the OLE1 promoter and trans factors are involved in the increased expression of OLE1 in sake yeasts.