白蜡虫蜡酯合酶基因cDNA全长克隆及原核表达

Cloning and Prokaryotic Expression of Wax Synthase Gene of the Chinese White Wax Scale

白蜡虫（Ericerus pela）是我国特有的资源昆虫,泌蜡是白蜡虫二龄雄虫最为特化的性状[1]。白蜡虫分泌的白蜡在食品、医药、纺织等行业具有重要的经济价值[2]。白蜡的主要成分是26酸26酯[3],已有研究表明,蜡酯的生物合成在动植物中存在保守途径[4]。蜡酯生物合成的第一步由脂酰辅酶A还原酶催化脂酰辅酶A转化为脂肪醇,第二步由蜡酯合酶（WS）催化脂肪醇和脂肪酸的酯化反应[5]。

[ Objective]To obtain the full length cDNA sequence of the wax synthase （ws） gene of the white wax in- sect, Ericerus pela Chavannes, and heterologously express the enzyme in Escherichia coli. [ Method] The 3＇ and 5＇ ends of the ws gene were obtained separately by using RACE, and the prokaryotic expression vector was constructed after [he analysis of the full length cDNA sequence of the ws gene. Finally, the expression of WS in Ericerus coli BL21 was induced by IPTG. [ Result ] Sequence analysis showed that, the full-length eDNA of the ws gene was 1 518 bp, which included the 5＇-UTR （untranslated region） with 94 bp, 3＇-UTR with 68 bp, and the open reading frame with 1 356 bp. The gene was deduced to encode 452 amino acid residues with the putative protein molecular weight of 51.8 kDa, and the theoretical isoeleetric point of 6.35. Western Blot result showed that, the WS enzyme was expressed suceessfully in Ericerus coli. [ Conclusion] In this study, the full length eDNA of the ws gene of Ericerus pela was obtained, and this enzyme was successfully expressed in Ericerus coli, which provides references for the research on wax ester synthesis in other insects.