THE FITNESS OF DEFECTIVE INTERFERING MURINE CORONAVIRUS-DI-A AND ITS DERIVATIVES IS DECREASED BY NONSENSE AND FRAMESHIFT MUTATIONS
THE FITNESS OF DEFECTIVE INTERFERING MURINE CORONAVIRUS-DI-A AND ITS DERIVATIVES IS DECREASED BY NONSENSE AND FRAMESHIFT MUTATIONS
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DOI：
10.1128/jvi.66.10.5898-5905.1992
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发表时间：
1992-10-01
影响因子：
5.4
通讯作者：
SPAAN, WJM
中科院分区：
文献类型：
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作者：
DEGROOT, RJ;VANDERMOST, RG;SPAAN, WJM
缺陷型干扰（DI）小鼠肝炎病毒DI-a的基因组携带由ORF 1a、ORF 1b和核衣壳序列组成的大开放阅读框（ORF）。为了测试该融合ORF是否对DI病毒复制重要，我们构建了DI-α基因组的衍生物，其中阅读框被无义密码子或移码突变截短。将体外转录的DI RNA转染到小鼠肝炎病毒感染的细胞中，然后将所得病毒-DI病毒原液未经稀释传代。提出了以下意见。(i)融合ORF的截短不是致命的，但导致DI RNA的积累减少。(ii)当通过共转染直接比较成对的几乎相同的框内和框外DI RNA时，含有框内基因组RNA的DI病毒在三次连续传代内占优势，即使当框外RNA以10倍摩尔过量转染时。(iii)当传代含有框外基因组RNA的DI病毒时，出现突变体，并选择恢复阅读框的突变体。我们的结论是，翻译的融合ORF确实需要有效的传播DI-α及其衍生物。
The genome of the defective interfering (DI) mouse hepatitis virus DI-a carries a large open reading frame (ORF) consisting of ORF1a, ORF1b, and nucleocapsid sequences. To test whether this fusion ORF is important for DI virus replication, we constructed derivatives of the DI-a genome in which the reading frame was truncated by a nonsense codon or a frameshift mutation. In vitro-transcribed DI RNAs were transfected into mouse hepatitis virus-infected cells followed by undiluted passage of the resulting virus-DI virus stocks. The following observations were made. (i) Truncation of the fusion ORF was not lethal but led to reduced accumulation of DI RNA. (ii) When pairs of nearly identical in-frame and out-of-frame DI RNAs were directly compared by cotransfection, DI viruses containing in-frame genomic RNAs prevailed within three successive passages even when the out-of-frame RNAs were transfected in 10-fold molar excess. (iii) When DI viruses containing out-of-frame genomic RNAs were passaged, mutants emerged and were selected for that had restored the reading frame. We conclude that translation of the fusion ORF is indeed required for efficient propagation of DI-a and its derivatives.