A Cell-Free Protein Synthesis System from Insect Cells
The Transdirect insect cell is a newly developed in vitro translation system for mRNA templates, which utilizes an extract from cultured Spodoptera frugiperda 21 (Sf21) insect cells. An expression vector, pTD1, which includes a 5′-untranslated region (UTR) sequence from a baculovirus polyhedrin gene as a translational enhancer, was also developed to obtain maximum performance from the insect cell-free protein synthesis system. This combination of insect cell extract and expression vector results in protein productivity of about 50 μg/mL of the translation reaction mixture. This is the highest protein productivity yet noted among commercialized cell-free protein synthesis systems based on animal extracts.
KeywordsTranslation Spodoptera frugiperda 21 Cell-free protein synthesis system pTD1 vector Insect cell extract
We thank Dr. Osamu Ohara and Dr. Takahiro Nagase, Kazusa DNA Research Institute, for valuable discussions. We also thank Dr. Sumiharu Nagaoka, Kyoto Institute of Technology, Dr. Toshihiko Utsumi, University of Yamaguchi, and Dr. Susumu Tsunasawa, Shimadzu Corporation, for helpful discussions.