AUTHOR=Wang Xiao-yin , Du Qiu-jie , Zhang Wei-li , Xu Dan-hua , Zhang Xi , Jia Yan-long , Wang Tian-yun 

TITLE=Enhanced Transgene Expression by Optimization of Poly A in Transfected CHO Cells

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2022.722722

DOI=10.3389/fbioe.2022.722722

ISSN=2296-4185

ABSTRACT=<p>The generation of the stable, high-level recombinant protein-producing cell lines remains a significant challenge in the biopharmaceutical industry. Expression vector optimization is an effective strategy to increase transgene expression levels and stability, and the choice of suitable poly A element is crucial for the expression of recombinant protein. In this study, we investigated the effects of different poly A elements on transgene expression in Chinese hamster ovary (CHO) cells. Five poly A elements, including bovine growth hormone (BGH), mutant BGH, herpes simplex virus type 1 thymidine kinase (HSV-TK), SV40, and a synthetic (Synt) poly A, were cloned into the expression vector and transfected into CHO cells. The results indicated the SV40 and Synt poly A sequences can significant improve <italic>eGFP</italic> transgene expression in stable transfected CHO cells and maintain long-term expression. However, qPCR results showed that the <italic>eGFP</italic> expression at protein level was not related to the gene copy number and mRNA level. Importantly, the SV40 and Synt poly A elements decreased the variation of <italic>eGFP</italic> transgene expression. Furthermore, it also showed that the SV40 and Synt poly A elements induced higher levels of adalimumab expression. In conclusion, SV40 poly A and Synt poly A are stronger elements that increase stable transgene expression and decrease the variation of expression, and the choice of suitable poly A element is helpful to improve the expression of recombinant protein.</p>