Human genome-derived TOP1 matrix attachment region enhances transgene expression in the transfected CHO cells

• Published in: Biotechnology letters Vol. 41; no. 6-7; pp. 701 - 709
• Main Authors: Jia, Yan-Long, Guo, Xiao, Wang, Xi-Cheng, Wang, Tian-Yun
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2019; Springer Nature B.V
• Subjects: Applied Microbiology; Biochemistry; Biomedical and Life Sciences; Biotechnology; Colonies; Copy number; Deoxyribonucleic acid; DNA; DNA topoisomerase; Fluorescence; Gene expression; Genomes; Heterogeneity; Life Sciences; Mammalian cells; Matrix attachment regions; Microbiology; mRNA; Original Research Paper; Proteins; Stability; Toxicity; Transgenes; Transgene expression; Human DNA topoisomerase I gene (TOP1); Chinese hamster ovary cells; Matrix attachment region (MAR)
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1007/s10529-019-02673-7

Objectives To investigate the effect of full-length fragment of DNA topoisomerase I gene (TOP1) matrix attachment regions (MARs) originating from the human genome on transgene expression in Chinese hamster ovary (CHO) cells and explore the underlying mechanisms. Results Results showed that TOP1 MAR cannot only enhance the transient and stable transgenic expression of enhanced green fluorescence protein (EGFP) but also increase long-term stability and ratio of positive colonies in transfected CHO cells with TOP1 MAR at the 5′ or 3′ ends of the EGFP expression cassette. Interestingly, the CHO cells were transfected with the 5′,3′ TOP1 MAR-containing vector featured the highest transient and stable expression, whereas those with the 3′ TOP1 MAR-containing vector exhibited the most effective stability and ratio of positive colonies. We also observed that transgene copy numbers and mRNA of egfp gene were correlated with the expression levels of EGFP protein in polyclonal CHO cells. However, the heterogeneity of expression in monoclonal CHO cells was unaffected by transgene copy number. Conclusions The findings may aid in the potential application of TOP1 MAR in expression enhancement of recombinant proteins in mammalian cells.