Two scaffold/matrix attachment regions (S/MARs) from Chinese hamster ovary (CHO) cell chromosomes were identified computationally and cloned as the domain boundaries regions. As partition chromosomes in independently regulated units to increase the exogenous gene expression, these two S/MARs (MAR1 and MAR6) flanked expression vectors were respectively transfected into CHO cells. The results showed that MAR1 and MAR6 were much more potent to increase the stable transfection efficiency than the chicken lysozyme gene 5' S/MARs, which had been experimentally identified to increasing the expression of heterologous gene. Moreover, MAR6 is more active in mediating high and consistent gene expression in CHO cells than the chicken lysozyme gene 5' S/MARs.

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In recent years, as the demand for precision nutrition is continuously increasing, scientific studies have shown that high-purity eicosapentaenoic acid ethyl ester (EPA-EE) functions more efficiently than mixed omega-3 polyunsaturated fatty acid preparations in diseases such as hyperlipidemia, heart disease, major depression, and heart disease; therefore, the market demand for EPA-EE is growing by the day. In this paper, we attempt to review EPA-EE from a whole-manufacturing-chain perspective. First, the extraction, refining, and ethanolysis processes (fish oil and ethanol undergo transesterification) of EPA-EE are described, emphasizing the potential of green substitute technologies. Then, the method of EPA enrichment is thoroughly detailed, the pros and cons of different methods are compared, and current developments in monomer production techniques are addressed. Finally, a summary of current advanced strategies for dealing with the low oxidative stability and low bioavailability of EPA-EE is presented. In conclusion, understanding the entire production process of EPA-EE will enable us to govern each step from a macro perspective and accomplish the best use of EPA-EE in a more cost-effective and environmentally friendly way.