Majors Brian S, Chiang Gisela G, Betenbaugh Michael J
Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218-2694, USA.
Mol Biotechnol. 2009 Jun;42(2):216-23. doi: 10.1007/s12033-009-9156-x. Epub 2009 Apr 15.
Mutation and selection are the essential steps of evolution. Researchers have long used in vitro mutagenesis, expression, and selection techniques in laboratory bacteria and yeast cultures to evolve proteins with new properties, termed directed evolution. Unfortunately, the nature of mammalian cells makes applying these mutagenesis and whole-organism evolution techniques to mammalian protein expression systems laborious and time consuming. Mammalian evolution systems would be useful to test unique mammalian cell proteins and protein characteristics, such as complex glycosylation. Protein evolution in mammalian cells would allow for generation of novel diagnostic tools and designer polypeptides that can only be tested in a mammalian expression system. Recent advances have shown that mammalian cells of the immune system can be utilized to evolve transgenes during their natural mutagenesis processes, thus creating proteins with unique properties, such as fluorescence. On a more global level, researchers have shown that mutation systems that affect the entire genome of a mammalian cell can give rise to cells with unique phenotypes suitable for commercial processes. This review examines the advances in mammalian cell and protein evolution and the application of this work toward advances in commercial mammalian cell biotechnology.
突变和选择是进化的基本步骤。长期以来，研究人员一直在实验室细菌和酵母培养物中使用体外诱变、表达和选择技术来进化具有新特性的蛋白质，即定向进化。不幸的是，哺乳动物细胞的特性使得将这些诱变和全生物体进化技术应用于哺乳动物蛋白质表达系统既费力又耗时。哺乳动物进化系统对于测试独特的哺乳动物细胞蛋白质和蛋白质特性（如复杂糖基化）将是有用的。在哺乳动物细胞中进行蛋白质进化将能够产生只能在哺乳动物表达系统中进行测试的新型诊断工具和定制多肽。最近的进展表明，免疫系统的哺乳动物细胞可在其自然诱变过程中用于进化转基因，从而产生具有独特特性（如荧光）的蛋白质。在更广泛的层面上，研究人员表明，影响哺乳动物细胞整个基因组的突变系统可产生具有适合商业用途独特表型的细胞。本综述探讨了哺乳动物细胞和蛋白质进化方面的进展以及这项工作在商业哺乳动物细胞生物技术进展中的应用。
