Max von Pettenkofer Institute, Lehrstuhl Virologie, Feodor-Lynen-Strasse 25, München, Germany.
J Virol. 2011 Oct;85(19):10346-53. doi: 10.1128/JVI.00545-11. Epub 2011 Aug 3.
Murine cytomegalovirus (MCMV) Smith strain has been cloned as a bacterial artificial chromosome (BAC) named pSM3fr and used for analysis of virus gene functions in vitro and in vivo. When sequencing the complete BAC genome, we identified a frameshift mutation within the open reading frame (ORF) encoding MCMV chemokine homologue MCK-2. This mutation would result in a truncated MCK-2 protein. When mice were infected with pSM3fr-derived virus, we observed reduced virus production in salivary glands, which could be reverted by repair of the frameshift mutation. When looking for the source of the mutation, we consistently found that virus stocks of cell culture-passaged MCMV Smith strain are mixtures of viruses with or without the MCK-2 mutation. We conclude that the MCK-2 mutation in the pSM3fr BAC is the result of clonal selection during the BAC cloning procedure.
鼠巨细胞病毒 (MCMV) Smith 株已被克隆为细菌人工染色体 (BAC)，命名为 pSM3fr，并用于体外和体内分析病毒基因功能。在对完整 BAC 基因组进行测序时，我们在编码 MCMV 趋化因子同源物 MCK-2 的开放阅读框 (ORF) 内发现了一个移码突变。该突变将导致 MCK-2 蛋白截短。当小鼠感染 pSM3fr 衍生的病毒时，我们观察到唾液腺中的病毒产量减少，而通过修复移码突变可以逆转这种情况。在寻找突变来源时，我们始终发现细胞培养传代的 MCMV Smith 株病毒株是带有或不带有 MCK-2 突变的病毒混合物。我们得出结论，pSM3fr BAC 中的 MCK-2 突变是 BAC 克隆过程中克隆选择的结果。
