Subramanian S, Bhat R A, Rundell M K, Thimmappaya B
J Virol. 1986 Nov;60(2):363-8. doi: 10.1128/JVI.60.2.363-368.1986.
Human cells infected with adenovirus type 2 (Ad2) or Ad5 require VAI RNA for efficient translation of viral mRNAs at late times after infection. The Ad5 mutant dl-sub720 synthesized neither virus-associated I (VAI) nor VAII RNAs, and infection of human cells with this mutant resulted in reduced virion polypeptide synthesis. Infection of monkey cells with this mutant also resulted in drastic reduction of polypeptide synthesis compared with wild-type (WT) adenovirus infections. Steady-state levels of hexon-specific mRNA were found to be comparable in WT- and mutant-infected monkey cells. The in vitro translation experiments showed that double-mutant- and WT-infected cells contained comparable levels of translatable hexon mRNA (and other adenovirus late mRNAs), suggesting that the severe inhibition of hexon protein synthesis in the VA mutant involves a translation block. Preinfection of monkey cells with simian virus 40 fully restored the efficient translation of this mRNA in the VA mutant infections to the level observed in WT-infected cultures. These results raise the possibility that simian virus 40 may encode or induce factors that suppress the translation block that occurs during adenovirus infections in the absence of the VA RNAs.
感染2型腺病毒（Ad2）或Ad5的人类细胞在感染后期需要VAI RNA才能有效翻译病毒mRNA。Ad5突变体dl-sub720既不合成病毒相关I（VAI）RNA也不合成VAII RNA，用该突变体感染人类细胞会导致病毒体多肽合成减少。与野生型（WT）腺病毒感染相比，用该突变体感染猴细胞也会导致多肽合成大幅减少。在WT和突变体感染的猴细胞中，六邻体特异性mRNA的稳态水平相当。体外翻译实验表明，双突变体和WT感染的细胞中可翻译的六邻体mRNA（以及其他腺病毒晚期mRNA）水平相当，这表明VA突变体中六邻体蛋白合成的严重抑制涉及翻译阻滞。用猿猴病毒40预先感染猴细胞可将VA突变体感染中该mRNA的有效翻译完全恢复到WT感染培养物中观察到的水平。这些结果增加了一种可能性，即猿猴病毒40可能编码或诱导抑制在没有VA RNA的情况下腺病毒感染期间发生的翻译阻滞的因子。
