Novel short synthetic matrix attachment region for enhancing transgenic expression in recombinant Chinese hamster ovary cells

• Published in: Journal of cellular biochemistry 2019-10, Vol.120 (10), p.18478-18486
• Main Authors: Jia, Yan‐Long, Guo, Xiao, Ni, Tian‐Jun, Lu, Jiang‐Tao, Wang, Xiao‐Yin, Wang, Tian‐Yun
• Format: Article
• Language: English
• Subjects: Bioinformatics; Chinese hamster ovary cell (CHO); Copy number; Deoxyribonucleic acid; DNA; Expression vectors; Fluorescence; Gene expression; Glutathione; Mammalian cells; matrix attachment region (MAR); Matrix attachment regions; Menopause; synthetic biology; Toxicity; Transfection; transgenic expression
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.29165

Matrix attachment regions (MARs) are DNA fragments with specific motifs that enhance transgenic expression; however, the characteristics and functions of these elements remain unclear. In this study, we designed and synthesized three short chimeric MARs, namely, SM4, SM5, and SM6, with different numbers and orders of motifs on the basis of the features and motifs of previously reported MARs, namely, SM1, SM2, and SM3, respectively. Expression vectors with six synthetic MARs flanking the down or upstream of the expression cassette for enhanced green fluorescence protein (EGFP) were constructed and introduced into Chinese hamster ovary (CHO) cells. Results indicated that the EGFP expression of the CHO cells with transfection bySM4, SM5, or SM6‐containing vectors was higher than that of those containing SM1, SM2, or SM3 regardless of the MAR insertion position. The improving effect of SM5 was particularly pronounced. Transgenic expression was further enhanced with the increasing SM5 copy number. Bioinformatics analysis indicated that several arrangements of the DNA‐binding motifs for CEBP, FAST, Hox, glutathione, and NMP4 may help increase transgenic expression levels and the average population of highly expressed cells. Our findings on novel synthetic MARs will help establish stable expression systems in mammalian cells. 1. The three synthetic matrix attachment regions (MARs) can improve transient enhanced green fluorescence protein (EGFP) expression level in Chinese hamster ovary cell (CHO) cells. 2. The CHO cells transfected with p3‐SM5 vector improved stable transgenic expression by 5.3‐fold. 3. The enhancing effect was heightened with the increasing copy number of this synthetic MARs.