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利用基因工程,可将外源基因导入大肠杆菌或其它工程细胞,使其作为生物工厂生产人类需要的蛋白质。在利用大肠杆菌表达外源基因时,必须考虑表达的基因载体、外源基因的性质、原核细胞启动子、读码框架及宿主菌调控系统这5个基本条件。本文结合笔者工作,介绍提高外源基因在大肠杆菌表达效率的一些技术进展。为提高外源基因转录水平,可选择合适的启动子、改进宿主菌调控系统和引入转录终止区。在提高外源基因转译水平方面,需改善核糖体结合点结构,考虑密码子使用的问题和增加mRNA稳定性。为提高外源蛋白的稳定性,可选择蛋白酶缺陷的宿主菌、注意蛋白质N端规律,或利用外泌型表达基因载体。
Using genetic engineering, foreign genes can be introduced into Escherichia coli or other engineered cells, making it a bio-factory producing proteins for human needs. In the use of E. coli expression of foreign genes, we must consider the expression of the gene vector, the nature of foreign genes, prokaryotic promoters, reading frames and host bacterial control system of these five basic conditions. In this paper, I work with the author to introduce some of the technical advances to improve the efficiency of expression of foreign genes in E. coli. In order to improve the transcription level of exogenous gene, a suitable promoter may be selected to improve the host bacterial regulatory system and to introduce a transcription termination region. In improving the level of foreign gene translation, the need to improve ribosome junction structure, consider the issue of codon usage and increase mRNA stability. In order to improve the stability of the foreign protein, the protease-deficient host bacteria can be selected, the protein N-terminal regulation can be taken, or the exogenous gene expression vector can be used.