De Benedetti A, Pytel B A, Baglioni C
Proc Natl Acad Sci U S A. 1987 Feb;84(3):658-62. doi: 10.1073/pnas.84.3.658.
An expression vector was constructed that carries part of the human BK papovavirus with 0.5 kilobases of (2'-5')oligoadenylate (2-5A) synthetase cDNA inserted in inverted orientation downstream from the virion proteins (VP) promoter and the neomycin-resistance gene neo under the control of a simian virus 40 promoter. Cells transfected with this vector and selected for resistance to the neomycin derivative G418 synthesized RNA complementary to 2-5A synthetase mRNA. These cells lacked 2-5A synthetase activity, and the enzyme was not inducible by interferon. In contrast, 2-5A synthetase was induced in cells transfected with a control vector without the cDNA insert. Such cells were protected by interferon from RNA viruses, whereas cells lacking 2-5A synthetase were not protected from encephalomyocarditis virus, vesicular stomatitis virus, and Sindbis virus but were fully protected from influenza virus. These findings show that a high level of 2-5A synthetase is required for interferon-induced protection from the cytoplasmic RNA viruses tested.
构建了一种表达载体，其携带人BK多瘤病毒的一部分，0.5千碱基的（2'-5'）寡腺苷酸（2-5A）合成酶cDNA以反向方向插入病毒体蛋白（VP）启动子下游，新霉素抗性基因neo在猴病毒40启动子的控制下。用该载体转染并选择对新霉素衍生物G418有抗性的细胞合成了与2-5A合成酶mRNA互补的RNA。这些细胞缺乏2-5A合成酶活性，并且该酶不受干扰素诱导。相反，在转染了无cDNA插入片段的对照载体的细胞中，2-5A合成酶被诱导。此类细胞受到干扰素对RNA病毒的保护，而缺乏2-5A合成酶的细胞不受脑心肌炎病毒、水疱性口炎病毒和辛德毕斯病毒的保护，但完全受流感病毒的保护。这些发现表明，干扰素诱导的对所测试的细胞质RNA病毒的保护需要高水平的2-5A合成酶。
