Improvement of Tol2 Transposon System Enabling Efficient Protein Production in CHO Cells

Establishment of mammalian cell lines with high protein productivity is an important object in the field of biopharmaceutics. Toward this end, Tol2 transposon-based expression systems have been developed as effective means to facilitate protein productivity. Here, we proposed novel strategies to improve conventional Tol2 transposon systems. The use of Tol2 transposase mRNA as a helper vector improved the efficiency of transgene integration and protein production. Moreover, the use of the Tol2 transposon vector containing the minimum cis-sequences essential for transposition (mini-TP) also served as one of the efficient means to generate recombinant cells that enable higher protein production. Furthermore, mini-TP showed a more beneficial response to DNA methylation inhibitors, suggesting that the use of mini-TP with DNA methylation inhibitors could be used as a means of commercial production. Taken together, our results provide effective strategies to improve the Tol2 transposon-based expression system. These strategies will be applicable to the production of therapeutic proteins and open new avenues in biopharmaceutical research.