High level expression and purification of recombinant PEX protein in cultured skeletal muscle cell expression system

Large quantities of recombinant proteins are needed for specific therapeutic and diagnostic applications. To achieve high-level expression in eukaryotic cells, the choice of cell line as well as the expression vector is critical. In this report, we demonstrate that a combination of the skeletal muscle cell line, QM7 and a cytomegalovirus promoter-based expression vector can achieve high-level expression of secretory recombinant proteins in eukaryotic cells. We also screened a serum-free medium containing 3 μg/ml insulin suitable for QM7 differentiation and identified a very potent signal peptide from MMP9, which effectively directs secretion of heterologous proteins. The C-terminal hemopexin-like domain of MMP-2, PEX, a powerful candidate for the treatment of diseases associated with neovascularization was expressed in QM7 cells with bioactivity. This skeletal muscle cell-based system may be employed for the production of human proteins of special interests, such as those for structural determination or therapeutical development.