Kerr I M, Brown R E, Tovell D R
J Virol. 1972 Jul;10(1):73-81. doi: 10.1128/JVI.10.1.73-81.1972.
The polypeptide products synthesized at different times in a cell-free system from Krebs mouse ascites tumor cells in response to the addition of encephalomyocarditis (EMC) virus ribonucleic acid (RNA) were characterized by electrophoresis on polyacrylamide gels and fingerprint analysis of their tryptic peptides. Translation of the EMC RNA genome with time occurred in a nonrandom fashion in these systems, to yield products containing sequences characteristic of both virion capsid polypeptides and EMC-specific polypeptides present only in the infected cell. The molecular weights of the products fell in a series from 20,000 to 140,000 daltons, although occasionally traces of larger polypeptides were also observed. All of the major polypeptides appeared to arise from partial or complete translation of about 60% of the EMC RNA genome. They were not formed by cleavage of a large precursor molecule. It is suggested that they are artifacts generated by premature "termination" of nascent polypeptide chains at preferred sites.
在无细胞系统中，用克氏小鼠腹水肿瘤细胞，于不同时间添加脑心肌炎（EMC）病毒核糖核酸（RNA）后合成的多肽产物，通过聚丙烯酰胺凝胶电泳及其胰蛋白酶解肽的指纹分析进行表征。在这些系统中，EMC RNA基因组随时间的翻译以非随机方式发生，产生的产物含有病毒粒子衣壳多肽和仅存在于受感染细胞中的EMC特异性多肽的序列特征。产物的分子量范围为20,000至140,000道尔顿，尽管偶尔也观察到痕量的较大多肽。所有主要多肽似乎都来自EMC RNA基因组约60%的部分或完全翻译。它们不是由大的前体分子裂解形成的。有人提出，它们是新生多肽链在优选位点过早“终止”产生的假象。
