Page M J
Gene. 1985;37(1-3):139-44. doi: 10.1016/0378-1119(85)90266-5.
An expression cassette consisting of the human beta-interferon (beta-IFN) cDNA fused to the human metallothionein (MeT)IIA promoter has been linked to a selectable mouse dihydrofolate reductase gene (dhfr) and used to transform dhfr-deficient Chinese hamster ovary (CHO) cells. Transformants resistant to increasing concentrations of methotrexate (Mtx) were isolated and found to secrete beta-IFN either constitutively or upon induction with cadmium (up to 325 000 units beta-IFN/10(6) cells/24 h). Molecular analysis demonstrates a large increase in beta-IFN-specific DNA sequences and beta-IFN mRNA levels in amplified cell lines, with initiation of transcription occurring at the authentic start point for the MeT promoter.
一个由与人金属硫蛋白（MeT）IIA启动子融合的人β-干扰素（β-IFN）cDNA组成的表达盒已与一个可选择的小鼠二氢叶酸还原酶基因（dhfr）相连，并用于转化缺乏dhfr的中国仓鼠卵巢（CHO）细胞。分离出对逐渐增加浓度的甲氨蝶呤（Mtx）有抗性的转化体，发现它们组成性地分泌β-IFN，或者在用镉诱导后分泌β-IFN（高达325000单位β-IFN/10⁶细胞/24小时）。分子分析表明，在扩增的细胞系中，β-IFN特异性DNA序列和β-IFN mRNA水平大幅增加，转录起始于MeT启动子的真实起始点。
