CHEF1®
The CHEF1 expression plasmid is the technological foundation of our cell line development platform.  Utilizing the regulatory sequences of the Chinese hamster EF-1a (CHEF1) gene, our vectors promote constitutive high level expression of recombinant proteins early in development.  The CHEF1 system allows rapid isolation of stable CHO cell lines because gene amplification is not required to achieve high level expression, saving many months of development. CHEF1 cell lines typically produce gram quantities of protein in 7 to 8 weeks from transfection and production-quality clones in 11 to 14 weeks.  A variety of CHEF1 vectors are available with different selectable markers permitting expression of heterodimeric proteins, as well as modification enzymes to improve product quality or expression levels.  The CHEF1 vectors have been successfully used to create manufacturing cell lines expressing a variety of different recombinant proteins including difficult-to-express glycoproteins.

• Hamster Elongation Factor Promoter: Constitutive Expression
• Rapid Cell Line Development: No Gene Amplification
• Multiple Selectable Markers: Protein Co-expression
• Stable, Low Copy Number Integrations
• Convenient, Multiple Cloning Sites