Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, USA
Transgenic plants as factories for high-value protein productions are attractive for a number of reasons. Chief among them is the potentially unlimited production capacity. However, most therapeutic proteins including antibodies are post-transcriptionally modified in mammalian cells by linking complex glycan sugars. The sugar modifications of proteins in plant cells are structurally different than those in mammalian cells. In many cases these differences have become a major obstacle for commercial production of protein pharmaceuticals using plants. Novel strategies are being used to address this issue. One of the proven strategies is to suppress the indigenous plant glycosylation machinery while introducing the mammalian glycosylation system into plants. Genome editing technologies allow precision modification of target genes. We have demonstrated that the indigenous plant glycosylation machinery can be altered by genome editing. In addition, we have successfully created artificial, multifunctional enzymes, enabling a single polypeptide to catalyze multiple reactions (e.g. those for a complete glycosylation pathway). These technologies can be combined to create an efficient yet simple plant gene expression system that can replace the plant glycosylation machinery with a mammalian one. The transgenic plants thus generated will permit protein modifications similar to those in mammalian cells.
Keywords: Genome editing, plant biotechnology,