UNIT 16.23 Amplification Using CHO Cell Expression Vectors
Published Online: 1 NOV 2002
Copyright © 2003 by John Wiley and Sons, Inc.
Lab Protocol Title
Current Protocols in Molecular Biology
How to Cite
Kingston, R. E., Kaufman, R. J., Bebbington, C.R. and Rolfe, M.R. 2002. Amplification Using CHO Cell Expression Vectors. Current Protocols in Molecular Biology. 60:16.23.1–16.23.13.
- Published Online: 1 NOV 2002
- Published Print: OCT 2002
The ability to select for integration of plasmid DNA into the host chromosome allows the generation of stably transfected cell lines. With transfection of a selectable marker linked to a nonselectable target gene (or by cotransfection of the two unlinked genes), high-level expression of the desired gene is obtained by selecting for amplification of the selectable marker. This unit presents two systems for gene amplification and expression. The first describes the dihydrofolate reductase (DHFR) selection system while the second is based on selection of the glutamine synthetase (GS) gene. The DHFR system is probably more widely used, and results in very high levels of amplification and expression; however, the DHFR amplification process is lengthy and may require several months to isolate and characterize a stable, amplified line. In contrast, the GS system typically requires only a single round of selection for amplification to achieve maximal expression levels.