[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 continuous 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-S2 system uses the popular and genetically well understood Drosphila S2 cells which do not appear to be lysed after infection. In mammalian 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.