真核表达系统的研究进展

真核表达系统具有翻译后的加工修饰体系 ,表达的外源蛋白更接近于天然蛋白质。基因工程中常用的真核表达系统有 :酵母表达系统、昆虫细胞表达系统及哺乳动物细胞表达系统。甲醇酵母主要利用醇氧化酶的基因启动子在甲醇诱导下表达外源蛋白 ,而三磷酸甘油脱氢酶启动不需甲醇诱导 ,可缩短到达峰值表达的时间。杆状病毒是昆虫细胞表达系统中最常用的表达载体 ,利用转座原理构建重组杆状病毒是一种有效的构建重组体的方法 ;杆状病毒 S2 系统是最近构建的一种不裂解宿主细胞的新型昆虫细胞表达系统。哺乳动物细胞表达系统中 ,腺病毒是常用的表达载体 ,通过细菌内同源重组和Cre/loxp系统构建重组体 ,可提高重组效率 ;利用杆状病毒将外源基因导入哺乳动物细胞 ,不会引起病毒基因的表达 ;四环素诱导表达系统是目前应用最广泛的哺乳动物细胞诱导表达系统 ,该系统具有严密、高效、可控性强的特点

Advances in Eukaryotic Expression Systems

The increasing popularity of eukaryotic expression systems can be attributed to their capability of performing many post translational modifications. At present, There mainly are three expression systems including yeast expression system, insect cell expression system and mammalian cell expression system. The methylotropic yeast Pichia Pastoris usually utilizes alcohol oxidase promoter to drive the expression of foreign gene. Recently, a continous fermentation has been developed in Pichia Pastoris with the glyceraldehyde 3 phosphate dehydrogenase (GAP)promoter. The baculovirus mediated insect cell expression system is considered to be safe, powerful, but cell lytic. Baculovirus S 2 system uses the popular and genetically well understood Drosphila S 2 cells which do not appear to be lysed after infection. In mammlian cell expression system, recombinant adenovirus are attracting a great deal of attention as a highly efficient gene transfer vehicle. The frequency of Ad vector rescue by homologous recombination in E. coli and Cre mediated site specific recombination is significantly higher than by homologous recombination in vivo . Tetracycline regulatable system is a widely used mammalian cell inducible expression system due to its high efficiency and stringency.