Mammalian Cells For Protein Expression

Expression vectors are the basic tools in biotechnology for the production of proteins.

Mammalian cells for protein expression.

In mammalian expression systems the protein or complex can be expressed in its native cell type under physiological conditions with numerous molecular systems working together for efficient production and quality control. Expression of a large complex protein containing multiple subunits cofactors disulphide bonds and posttranslational modifications is a quite challenging mahmoud 2007 since the posttranslational metabolic machinery is only available in mammalian cells butler 2005 zhang 2010. To conclude one of the main ideas to keep in mind is that recombinant protein expression in mammalian cells increases their compatibility for further human use. Mammalian cell expression systems hek293 and cho the main challenge of using mammalian cells for expressing recombinant proteins is the reduced efficiency and levels of the protein expressed.

An expression vector otherwise known as an expression construct is usually a plasmid or virus designed for gene expression in cells. However cell lines such as hek293 and cho have been developed as efficient transient and stable expression systems respectively. Many proteins can be expressed at high level in escherichia coli. Unfortunately the large scale expression of eukaryotic proteins in a stable and soluble form is still a major bottleneck.

The vector is used to introduce a specific gene into a target cell and can commandeer the cell s mechanism for protein synthesis to produce the protein encoded by the gene. However pro kary otic expression systems fail to generate correctly folded functional forms of many eukaryotic proteins and hence a variety of eukaryotic based expression systems have been developed 1. Complex glycosylation and accurate protein folding tasks where e. Protein expression in mammalian cells.

It is designed for high yield transient expression and display of mammalian cell surface membrane proteins including g protein coupled receptors gpcrs in an aqueous soluble format. Mammalian cells are generally more difficult to work with than bacteria since they are much more fragile often produce less product overall and can be much more expensive. The use of mammalian cells for the expression of recombinant proteins particularly of secreted proteins gains widespread use. When biopharmaceuticals are produced with one of these systems process related impurities termed host cell proteins also arrive in the final product in trace amounts.

Mammalian cells protein expression also allows for proper protein folding a determining criteria to prevent the loss of biological activity. Commonly used protein production systems include those derived from bacteria yeast baculovirus insect mammalian cells and more recently filamentous fungi such as myceliophthora thermophila. Recombinant protein expression in mammalian cells hek293 cho introduction to expression in mammalian cells.