外源基因在甲醇酵母Pichia pastoris中的表达策略

Strategies for the Expression of Foreign Genes in the Methylotrophic Yeast Pichia Pastoris

甲醇酵母 Ｐｉｃｈｉａ ｐａｓｔｏｒｉｓ表达系统是近几年发展起来的一个真核表达系统，在其乙醇氧化酶 ＡＯＸ１基因启动子的控制下，某些外源基因（如 ＴＮＦ、ＥＧＦ等）的表达量可达克每升以上。虽然该系统是一种优良的表达系统，但有许多因素影响外源基因在其中的表达，包括外源基因的拷贝数及整合到酵母染色体的位置和方式、ｍＲＮＡ的５’和３’非翻译区（ＵＴＲ）、转录起始密码子的上下文、外源基因Ａ＋Ｔ的组成与转录和翻译的阻断、密码子的偏爱性、信号肽的特性、产物的稳定性、宿主菌的生理特性、培养基成分和培养条件等。在应用该表达系统过程中，这些因素都需加以考虑。本文将就这些因素作一概述和讨论，以有利于提高外原基因在该系统中的表达水平。

The methylotrophic yeast Pichia pastoris expression system has been developed recently . Under the control of the AOX1 pro- moter, foreign genes, such as tumor tumor necrosis factor(TNF) and mouse epidermal growth factor(ECF), have ben expressed at a level of up to more than 1 gram per liter medium in this expression system. Many factors influence the expression level of foreign genes in the system,includ- ing; copy number, A + T composition , and locus and mode of chromosomal integration of the forei...