Friedman R M, Metz D H, Esteban R M, Tovell D R, Ball L A, Kerr I M
J Virol. 1972 Dec;10(6):1184-98. doi: 10.1128/JVI.10.6.1184-1198.1972.
Encephalomyocarditis (EMC) virus ribonucleic acid (RNA) stimulated the incorporation of (14)C-amino acids into polypeptides in cell-free systems using preincubated S10 extracts from L cells. Incorporation was linear for over 2 hr. Analysis of the tryptic peptides derived from the polypeptide products formed in response to EMC RNA showed them to be virus specific. The major product, a polypeptide of 140,000 in molecular weight, migrated on sodium dodecyl sulfate-polyacrylamide gels with one of the virus-specific polypeptides present in EMC-infected cells. A minor component of molecular weight about 230,000 may correspond to the product of complete translation of the EMC virus genome. Little or no effect of interferon or vaccinia virus infection was observed in the preincubated, cell-free system. The EMC RNA-stimulated incorporation of (14)C-amino acids into polypeptides was not inhibited in extracts derived from L cells early in virus infection, from interferon-treated cells, or from cells subjected to both treatments. Interferon treatment did appear to have a slight inhibitory effect on chain elongation in this system. However, treatment of cells with highly purified interferon before virus infection caused a decrease of about 80% in the capacity of non-preincubated cell extracts to translate added EMC RNA. This effect did not extend to the translation of polyuridylic acid and could be reversed by preincubation of the extracts at 37 C for 20 min. The inhibition of translation was manifest at interferon concentrations as low as 5IU/ml, and in this respect closely paralleled the inhibition of virus growth. Inactivation of the antiviral activity of the interferon by heating or digestion with trypsin also abolished the effect on cell-free protein synthesis. The EMC-specific polypeptides formed in reduced amounts in extracts of interferon-treated vaccinia-infected cells were smaller than those formed in extracts of untreated, vaccinia-infected cells. Thus, inhibition of initiation or elongation of polypeptides, or both, can be demonstrated in cell-free systems employing non-preincubated extracts from interferon-treated, virus-infected cells. These results indicate that antiviral activity of interferon is directed against the translation of viral messenger RNA.
脑心肌炎（EMC）病毒核糖核酸（RNA）在使用预先孵育的L细胞S10提取物的无细胞系统中，刺激了（14）C-氨基酸掺入多肽。掺入在超过2小时内呈线性。对源自响应EMC RNA形成的多肽产物的胰蛋白酶肽分析表明它们是病毒特异性的。主要产物是一种分子量为140,000的多肽，在十二烷基硫酸钠-聚丙烯酰胺凝胶上与EMC感染细胞中存在的一种病毒特异性多肽一起迁移。分子量约为230,000的次要成分可能对应于EMC病毒基因组完全翻译的产物。在预先孵育的无细胞系统中，未观察到干扰素或痘苗病毒感染的影响很小或没有影响。EMC RNA刺激的（14）C-氨基酸掺入多肽在病毒感染早期的L细胞提取物、干扰素处理的细胞提取物或经过两种处理的细胞提取物中均未受到抑制。干扰素处理在该系统中似乎对链延伸有轻微的抑制作用。然而，在病毒感染前用高度纯化的干扰素处理细胞，导致未预先孵育的细胞提取物翻译添加的EMC RNA的能力下降约80%。这种效应未扩展到聚尿苷酸的翻译，并且可以通过将提取物在37℃预孵育20分钟来逆转。翻译抑制在低至5IU/ml的干扰素浓度下就很明显，在这方面与病毒生长的抑制密切平行。通过加热或用胰蛋白酶消化使干扰素的抗病毒活性失活也消除了对无细胞蛋白质合成的影响。在干扰素处理的痘苗感染细胞提取物中形成的EMC特异性多肽数量减少，且比未处理的痘苗感染细胞提取物中形成的多肽小。因此，在使用干扰素处理的病毒感染细胞的未预先孵育提取物的无细胞系统中，可以证明多肽起始或延伸或两者的抑制。这些结果表明干扰素的抗病毒活性针对病毒信使RNA的翻译。
