Human genome-derived TOP1 matrix attachment region enhances transgene expression in the transfected CHO cells
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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 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.
The findings may aid in the potential application of TOP1 MAR in expression enhancement of recombinant proteins in mammalian cells.
KeywordsChinese hamster ovary cells Human DNA topoisomerase I gene (TOP1) Matrix attachment region (MAR) Transgene expression
Enhanced green fluorescence protein
Matrix attachment region
Mean fluorescence intensity
Real-time quantitative PCR
Human DNA topoisomerase I gene
This work was supported by the Grants from the National Natural Science Foundation of China (No. 81673337), the Key Science and Technology Project of Henan (Grant Nos. 192102310149, 182102310194), the Key Scientific Research Projects in Universities of Henan Province (No. 18A350008), the National Natural Science Foundation of China (Grant No. U1804168), the Plan of Scientific and Technological Innovation Team for University, Henan Province, China (Grant No. 18IRTSTHN027) and the Industry-University-Research Project of Xinxiang Medical University (Grant No. 2017CXY-2-1).
Compliance with ethical standards
Conflict of interests
The authors declare that they have no conflict of interest.
- Tian ZW, Xu DH, Wang TY, Wang XY, Xu HY et al (2018) Identification of a potent MAR element from the human genome and assessment of its activity in stably transfected CHO cells. J Cell Mol Med 22:1095–1102Google Scholar