Innovative use of a bacterial enzyme involved in sialic acid degradation to initiate sialic acid biosynthesis in glycoengineered insect cells
- PMID: 23022569
- PMCID: PMC3496044
- DOI: 10.1016/j.ymben.2012.08.005
Innovative use of a bacterial enzyme involved in sialic acid degradation to initiate sialic acid biosynthesis in glycoengineered insect cells
Abstract
The baculovirus/insect cell system is widely used for recombinant protein production, but it is suboptimal for recombinant glycoprotein production because it does not provide sialylation, which is an essential feature of many glycoprotein biologics. This problem has been addressed by metabolic engineering, which has extended endogenous insect cell N-glycosylation pathways and enabled glycoprotein sialylation by baculovirus/insect cell systems. However, further improvement is needed because even the most extensively engineered baculovirus/insect cell systems require media supplementation with N-acetylmannosamine, an expensive sialic acid precursor, for efficient recombinant glycoprotein sialylation. Our solution to this problem focused on E. coli N-acetylglucosamine-6-phosphate 2'-epimerase (GNPE), which normally functions in bacterial sialic acid degradation. Considering that insect cells have the product, but not the substrate for this enzyme, we hypothesized that GNPE might drive the reverse reaction in these cells, thereby initiating sialic acid biosynthesis in the absence of media supplementation. We tested this hypothesis by isolating transgenic insect cells expressing E. coli GNPE together with a suite of mammalian genes needed for N-glycoprotein sialylation. Various assays showed that these cells efficiently produced sialic acid, CMP-sialic acid, and sialylated recombinant N-glycoproteins even in growth media without N-acetylmannosamine. Thus, this study demonstrated that a eukaryotic recombinant protein production platform can be glycoengineered with a bacterial gene, that a bacterial enzyme which normally functions in sialic acid degradation can be used to initiate sialic acid biosynthesis, and that insect cells expressing this enzyme can produce sialylated N-glycoproteins without N-acetylmannosamine supplementation, which will reduce production costs in glycoengineered baculovirus/insect cell systems.
Copyright © 2012 Elsevier Inc. All rights reserved.
Figures







References
-
- Bork K, Reutter W, Gerardy-Schahn R, Horstkorte R. The intracellular concentration of sialic acid regulates the polysialylation of the neural cell adhesion molecule. FEBS Lett. 2005;579:5079–5083. - PubMed
-
- Bork K, Reutter W, Weidemann W, Horstkorte R. Enhanced sialylation of EPO by overexpression of UDP-GlcNAc 2-epimerase/ManAc kinase containing a sialuria mutation in CHO cells. FEBS Lett. 2007;581:4195–4198. - PubMed
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources