Improvement of Tol2 Transposon System by Modification of Tol2 Transposase

Tol2 transposon-based vector platform has been developed as a useful strategy to improve protein yield. Tol2 transposase identifies inverted terminal repeats of transposons and enhances transgene integration efficiency in the genome. However, Tol2 transposon system does not reach a level of efficiency for use in commercial production, limiting its usefulness for mass production of recombinant proteins. Here, we proposed a novel strategy to improve the existing Tol2 transposase by adding a nuclear localization signal of histone H2B next to the Tol2 transposase (i.e., NLS-H2B-Tol2 transposase). Comparing the NLS-H2B-Tol2 transposase with the traditional Tol2 transposase, a significant increase in protein production was measured. Concurrently, a significant increase in nuclear transport of NLS-H2B-Tol2 transposase was observed, suggesting a causal relationship between increased nuclear transport and increased protein production. Furthermore, importin beta maximized NLS-H2B-Tol2-mediated protein productivity. Taken together, our findings offer useful ways for improving conventional Tol2 transposon-based vector platform. This new platform will be a breakthrough in the field of biopharmaceuticals to produce therapeutic proteins.