Wang Tian-Yun, Yang Rui, Qin Chuan, Wang Li, Yang Xian-Jun
Department of Biochemistry and Molecular Biology, Jinsui Road, Xinxiang, Henan 453003, PR China.
Cell Biol Int. 2008 Oct;32(10):1279-83. doi: 10.1016/j.cellbi.2008.07.014. Epub 2008 Jul 25.
The expression of transgenes in mammalian cells is often at a low level mainly due to position effects from the neighboring chromatin context. To improve this, we have constructed a vector pCAM, which contains chloramphenicol acetyltransferase (CAT) reporter gene cassettes, driven by SV40 early promoter and flanked by two human beta-globin MARs in cis. We transfected this vector into the Chinese hamster ovary (CHO) cell line, and found that the level of CAT gene expression with MAR was effectively increased, about 5.493-fold higher than those without MARs. Moreover, the variations of CAT expression among individuals of transformants were decreased 2.670-fold. Our result also showed that MAR could increase the proportion of positive colonies in recombinants.
转基因在哺乳动物细胞中的表达水平通常较低，主要是由于邻近染色质环境的位置效应。为了改善这一情况，我们构建了载体pCAM，其包含由SV40早期启动子驱动的氯霉素乙酰转移酶（CAT）报告基因盒，并在顺式结构中两侧各有一个人β-珠蛋白基质附着区域（MAR）。我们将该载体转染到中国仓鼠卵巢（CHO）细胞系中，发现带有MAR的CAT基因表达水平有效提高，比没有MAR的情况高出约5.493倍。此外，转化体个体间CAT表达的变异减少了2.670倍。我们的结果还表明，MAR可以增加重组体中阳性菌落的比例。
