Baric R S, Yount B
Department of Epidemiology, Program in Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
J Virol. 2000 May;74(9):4039-46. doi: 10.1128/jvi.74.9.4039-4046.2000.
Mouse hepatitis virus (MHV)-infected cells contain full-length and subgenomic-length positive- and negative-strand RNAs. The origin and function of the subgenomic negative-strand RNAs is controversial. In this report we demonstrate that the synthesis and molar ratios of subgenomic negative strands are similar in alternative host cells, suggesting that these RNAs function as important mediators of positive-strand synthesis. Using kinetic labeling experiments, we show that the full-length and subgenomic-length replicative form RNAs rapidly accumulate and then saturate with label, suggesting that the subgenomic-length negative strands are the principal mediators of positive-strand synthesis. Using cycloheximide, which preferentially inhibits negative-strand and to a lesser extent positive-strand synthesis, we demonstrate that cycloheximide treatment equally inhibits full-length and subgenomic-length negative-strand synthesis. Importantly, following treatment, previously transcribed negative strands remain in transcriptionally active complexes even in the absence of new negative-strand synthesis. These findings indicate that the subgenomic-length negative strands are the principal templates of positive-strand synthesis during MHV infection.
感染小鼠肝炎病毒（MHV）的细胞含有全长和亚基因组长度的正链和负链RNA。亚基因组负链RNA的起源和功能存在争议。在本报告中，我们证明亚基因组负链在替代宿主细胞中的合成和摩尔比相似，这表明这些RNA作为正链合成的重要介质发挥作用。通过动力学标记实验，我们表明全长和亚基因组长度的复制形式RNA迅速积累，然后标记饱和，这表明亚基因组长度的负链是正链合成的主要介质。使用优先抑制负链且在较小程度上抑制正链合成的环己酰亚胺，我们证明环己酰亚胺处理同样抑制全长和亚基因组长度的负链合成。重要的是，处理后，即使在没有新的负链合成的情况下，先前转录的负链仍保留在转录活性复合物中。这些发现表明，亚基因组长度的负链是MHV感染期间正链合成的主要模板。
