Mammalian Expression Systems

Creative BioMart has decades of experience and expertise in both transient and stable expression based on HEK293 or CHO cell lines. Our advanced mammalian cell platform comprises improved promoters, signal sequences, vectors and transfection procedures. Additional yield enhancement through better expression and purification strategies further improves cost efficiency for the recombinant proteins.

What are Mammalian Expression Systems?

Mammalian cell expression system is one of the routine methods for protein production. The main advantage of mammalian cell expression is that the mammalian cells can properly and efficiently recognize the signals for synthesis, processing and secretion of eukaryotic proteins. Therefore expression systems utilizing mammalian cells for recombinant protein manufacture are able to introduce proper protein folding, post-translational modifications, and protein assembly, which are important for complete biological activity. Extending to the pharmaceutical field, almost all biopharmaceutical companies in the world rely on the use of mammalian-cell-based stable cell lines for the manufacture of biologics.

Advantages of Mammalian Expression Systems

• Proteins produced have similar structure and function to natural proteins
• Post-translational modifications such as glycosylation, phosphorylation, and acetylation
• Protein can be secreted into the medium, and the purification process is simple
• Easy transfection of recombinant DNA

Creative BioMart has extensive experience in vector optimization and has developed a set of proprietary vectors for preferred production cell types including HEK293 cells and CHO cells.

HEK293 Cells

• Human Embryonic Kidney cells
• The most commonly used line for transient production, not as frequently used for therapeutic protein production
• Easy to transfect
• Adaptable for suspension culture
• Transient expression

CHO Cells

• Chinese Hamster Ovary cells
• Predominant cell line for therapeutic protein production due to preferred post-translational modifications
• Adaptable for suspension culture
• Transient and stable expressions

Creative BioMart provides comprehensive mammalian cells expression service, including bioinformatics analysis, protein domain selection, tag selection, construct design, sequence verification, cell transfection, cell amplification, pilot expression, purification, yield optimization, scale up processing, and advanced protein analysis.

Service Content of Mammalian Expression Systems

1

Gene Synthesis Plus Codon Optimization

• Leading codon optimization system
• Analysis and optimization of rare codons, codon bias and other factors

Timeline: 1-2 weeks

2

Vector Construction

• Clone target gene into expression vector
• Plasmid sequencing
• Plasmid preparation

Timeline: 1 week

3

Protein Expression and Purification

• Transient transfection of HEK293/CHO cells
• Expression condition optimization
• Protein expression evaluation
• Various protein purification methods

Timeline: 2-3 weeks

4

Optional Services

• Tag removal
• Endotoxin removal
• Activity assay
• Protein analysis
• Other more

Timeline: 1-2 weeks

5

Quality Control

• SDS-PAGE
• Western blot
• Mass spectrometry

Timeline: <1 week

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Protein Purification Methods

• Affinity Chromatography
• Ion Exchange Chromatography
• Hydrophobic Interaction Chromatography
• Size Exclusion Chromatography

Reference:

1. Hacker D L, Balasubramanian S. Recombinant protein production from stable mammalian cell lines and pools. Current Opinion in Structural Biology. Volume 38, June 2016, Pages129-136