枇杷鲨烯合酶(Squalene synthase)基因的克隆及序列分析

Cloning and Sequence Analysis of Squalene Synthase Gene in Eriobotrya japonica L.

鲨烯合酶（SQS）是枇杷三萜酸生物合成过程中的关键酶。以枇杷（Eriobotrya iaponicn L．）悬浮培养细胞为材料，采用RT—PCR和RACE方法分离得到枇杷鲨烯合酶Ej-SQS（Squalene svnthase）基因的cDNA全长序列（GenBank，JQ294055），共1775bp，包含了5’非编码区为97bp，开放阅读框为1239bp，3’非编码区为439bp。该cDNA的开放阅读框推定的氨基酸序列（含412个氨基酸）与其它植物SQS具有79％～94％同源性．包含Trans_IPPS_HH保守结构域，可能属于Isoprenoid Biosynthesis enzymes，Class 1家族。为今后利用基因工程调控枇杷细胞悬浮培养物以提取目标产物奠定基础。

The cDNA of SQS （Squalene Synthase Gene）, which was an importent enzyme of terpenes synthesis, was cloned with RT-PCR and RACE from cell suspension culture of Eriobotrya japonica L. The full length of Ej- SQS cDNA （GenBank, JQ294055）, about 1 775 bp, consisted of an open reading frame of 1 239 bp, and 5＇ and 3＇ un-translated regions of 97 bp and 439 bp respectively. The putative protein had 412 amino acids, and the identity to the other polypeptides varied between 79%--94%, contained Trans_IPPS_HH conser,,et dotrains, and belonged to isoprenoid biosynthesis enzymes, class 1 family. It was the foundation of the furth.r regulation of loquat cell suspension cultures to extract the desired product, using genetic engineering.