ROSA26 BAC-based system enables continuous high-yield protein production

Abstract

The mouse ROSA26 locus serves as a port to maintain stable expression of the transgene. Therefore, a bacterial artificial chromosome (BAC) containing the ROSA26 locus was used as a platform to produce proteins by incorporating transgenes with foreign promoters. However, the endogenous promoter of the ROSA26 locus, which allows stable high-level transgene expression, has not been applied to the ROSA26 BAC-based platform. In this study, we generated recombinant ROSA26 BAC by targeting “exon 1” or “intron 1” of the ROSA26 locus. Recombinant ROSA26 BAC (exon 1) had lower protein productivity compared to the control. However, recombinant ROSA26 BAC (intron 1) produced protein at a higher efficiency than the control group. The protein productivity induction effect by recombinant ROSA26 BAC (intron 1) was maintained up to a single clone, enabling stable protein production over a long period of time. Taken together, we established a ROSA26 BAC-based protein production system capable of producing protein at high yield over a long period of time.