Construction of transgene-amplified CHO cell lines by cell cycle checkpoint engineering

Introduction Dihydrofolate reductase (DHFR)-mediated gene amplification has been widely used to establish high-producing mammalian cell lines [1-3]. However, since gene amplification is an infrequent event, in that many rounds of methotrexate (MTX) selection to amplify the transgene and screening of over several hundred individual clones are required to obtain cells with high gene copy numbers [4]. Consequently, the process for DHFR-mediated gene amplification is a time-consuming and laborious step for cell line construction. Here, we present a novel concept to accelerate gene amplification through cell cycle checkpoint engineering [5]. In our knowledge, there is no previous report which focused on controlling cell cycle checkpoint to enhance the efficiency of DHFR gene amplification system.