基因表达系统与转基因动物乳腺反应器

出于研究、医疗或工业目的，常常需要大量置备各种生物活性蛋白质，为此已经建立了多种基因工程表达系统，如微生物发酵系统、真核细胞培养系统、转基因植物表达系统和转基因动物表达系统等。近几年，利用转基因动物作为生物反应器由乳汁中生产蛋白药物的研究取得了很大进展，有多种动物可被用于转基因。基本过程是将基因构件显微注射到单细胞期受精卵，基因构件以一定几率整合到受体基因组中。通常转基因和其表达模式可忠实地遗传。许多蛋白将以高浓度低成本由转基因家畜的奶中生产。这些转基因动物与传统的动物细胞培养和细菌发酵技术相比尤显高效。乳腺能完成包括二硫桥形成、酰胺化、羧基化和糖基化在内的翻译后修饰，１头转基因羊就是１套发酵罐。据预测，到２０１０年由转基因动物生产的蛋白药物占全部基因工程药物的比率将增长到９５％以上。

Gene Expression Systems and the Mammary Reactors of Transgenic Animals

Large quantities of biological active proteins always are striven to produce for clinical use,science research use and industrial use.Many gene expression systems have been established.These involve microbial fermentation systems,eukaryocyte culture systems,transgenic plants systems,transgenic animals systems,and so on.In recent years,great progress has been made in the use of transgenic animals as bioreactors for the production of protein-based therapeutics in milk. Many species of animals can be made transgenic. The basic process involves microinjection of a DNA construct into the pro-nuclears of a one-cell fertilized egg.The DNA construct integrates into the host genome at a certain frequency. In general,the transgene and resulting expression patterns are transmitted faithfully from generation to generation.Many proteins will be produced at high concentration but low cost in the milk of transgenic livestock species. These transgenic animals are more cost effective when compared to convention technology such as the CHO cell and bacterical fermentation.The mammary gland can perform post-translational modifications,include disulphide bridge formation,amidation,carboxylation and glycosylation,One transgenic goat is one fementation tank. According to forecast, ratio of pharmacentical proteins produced by transgenic animals will increase to 95% in all gene pharmacentical proteins in 2010.