Krug R M, Morgan M A, Shatkin A J
J Virol. 1976 Oct;20(1):45-53. doi: 10.1128/JVI.20.1.45-53.1976.
Influenza viral complementary RNA (cRNA), i.e., viral mRNA was radioactive when purified from the cytoplasmic fraction of cordycepin-treated canine kidney cells that were incubated with [methyl-3H]methionine during infection. Approximately 55 to 60% of the methyl-3H radioactivity was in internal N6-methyladenosine, a feature distinguishing this mRNA from those viral mRNA's that are known to be synthesized in the cytoplasm. The remaining methyl-3H radioactivity was in 5'-terminal cap structures that consisted of 7-methylguanosine in pyrophosphate linkage to 2'-o-methyladenosine, N6, 2'-O-dimethyladenosine, or 2'-O-methylguanosine. Methylated adenosine was the predominant penultimate nucleoside in caps, suggesting that cRNA synthesis in infected cells initiates preferentially with adenosine at the 5' end. In contrast to cRNA, influenza virion RNA segments extracted from purified virus contained mainly 5'-terminal ppA and no detectable cap structures.
流感病毒互补RNA（cRNA），即病毒mRNA，在感染期间用[甲基-3H]甲硫氨酸孵育的经虫草素处理的犬肾细胞的细胞质部分中纯化时具有放射性。约55%至60%的甲基-3H放射性存在于内部N6-甲基腺苷中，这一特征将该mRNA与已知在细胞质中合成的那些病毒mRNA区分开来。其余的甲基-3H放射性存在于5'-末端帽结构中，该结构由与2'-O-甲基腺苷、N6,2'-O-二甲基腺苷或2'-O-甲基鸟苷以焦磷酸键相连的7-甲基鸟苷组成。甲基化腺苷是帽结构中主要的倒数第二个核苷，这表明感染细胞中的cRNA合成优先在5'端以腺苷起始。与cRNA相反，从纯化病毒中提取的流感病毒粒子RNA片段主要含有5'-末端ppA，且未检测到帽结构。
