L'Hote P, Alouani S, Marq J B, Montandon F, Chessebeuf-Padieu M, Dreano M
Department of Genetic Engineering, IntraCel S.A., Geneva-Carouge, Switzerland.
Cell Biol Toxicol. 1993 Oct-Dec;9(4):319-32. doi: 10.1007/BF00754460.
A plasmid carrying a DNA fragment of hepatitis B virus, coding for the pre-S2 and the entire S region of the surface antigen (HBsAg), placed under the control of the promoter of the human 70 kDa heat shock protein gene (hsp70), was introduced into Line 6, a recombinant cell line that was selected from NIH-3T3 cells previously transfected with a similar construct coding for the human growth hormone cDNA gene (chGH) and with the plasmid pEJ carrying the Ha-rasEJ activated cellular oncogene. The resulting cell line, EMS8, expressed: (1) hsp70/HBsAg and hsp70/hGH hybrid genes, (2) the human Ha-rasEJ oncogene, and (3) the neomycin resistance gene, the two last plasmid markers being used for cell selection. EMS8 cells were able to carry out post-translational modifications of the middle M and the major S envelope proteins of HBV, such as assembly and glycosylation. Accordingly, the cells synthesized and secreted both free and glycosylated M and S viral proteins, and the human growth hormone protein. In addition concomitant expression of HBsAg and hGH proteins as well as their mRNA were detected in EMS8 cells at least up to 72 hr after heat induction instead of 24 hr in the case of hGH in Line 6 cells.
将携带乙肝病毒DNA片段的质粒导入6号线细胞系。该DNA片段编码表面抗原（HBsAg）的前S2和整个S区，并置于人70kDa热休克蛋白基因（hsp70）启动子的控制之下。6号线细胞系是一种重组细胞系，它是从先前用编码人生长激素cDNA基因（chGH）的类似构建体以及携带Ha-rasEJ激活细胞癌基因的质粒pEJ转染的NIH-3T3细胞中筛选出来的。所得细胞系EMS8表达：（1）hsp70/HBsAg和hsp70/hGH杂交基因，（2）人Ha-rasEJ癌基因，以及（3）新霉素抗性基因，后两个质粒标记用于细胞筛选。EMS8细胞能够对乙肝病毒的中间M包膜蛋白和主要S包膜蛋白进行翻译后修饰，如组装和糖基化。因此，这些细胞合成并分泌游离的和糖基化的M和S病毒蛋白以及人生长激素蛋白。此外，在热诱导后至少72小时内，在EMS8细胞中检测到HBsAg和hGH蛋白及其mRNA的伴随表达，而在6号线细胞中，hGH的情况是在热诱导后24小时内检测到。
