关键词: DHA, 脂肪酸脱饱和酶, 脂肪酸延长酶, 甲醇诱导表达, 毕赤酵母

Abstract: DHA (docosahexaenoic acid) is a polyunsaturated fatty acid and essential for human being. Fishes and microalgae from marine are the main source of DHA product for now. DHA cant be synthetized by itself in higher plant, so it will be significant to create DHA crops by genetic engineering. In this study, five genes from marine microlgae which involved in DHA synthesis were cloned, including three fatty acid desaturase genes (D4, D5 and D6 genes encode Δ4, Δ5 and Δ6 fatty acid desaturase, respectively) and two elongase (E18 and E20 encode C18 and C20 fatty acid elongase, respectively). To confirm whether these optimized genes could express exactly in eukaryotes, the five target genes were cloned into pPIC9K and the resulting vectors were transformed into Pichia pastoris GS115 (His4+Muts). The results demonstrated the maximum proteins were obtained at 96 hours induced by methanol. Western Blot result showed that the expression product was target protein. These results laid the foundation for maize breeding containing DHA.

Key words: DHA, fatty acid desaturase, fatty acid elongase, methanol-induced expression, Pichia pastoris