REGULATION OF CORONAVIRUS MESSENGER-RNA TRANSCRIPTION
REGULATION OF CORONAVIRUS MESSENGER-RNA TRANSCRIPTION
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DOI：
10.1128/jvi.69.12.7851-7856.1995
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发表时间：
1995-12-01
影响因子：
5.4
通讯作者：
SPAAN, WJM
中科院分区：
文献类型：
--
作者：
VANMARLE, G;LUYTJES, W;SPAAN, WJM
冠状病毒在受感染的细胞中合成一套由6到8个亚基因组(Sg)mRNAs组成的嵌套组。这些核糖核酸以不同但恒定的摩尔比例产生。目前还不清楚哪些因素控制着不同水平的sg mRNAs。为了确定参与sg mRNA合成的基因间序列(IS)是否会影响其他ISS的转录效率并通过这种方式调节转录水平，我们在小鼠肝炎病毒缺陷干扰RNA中插入了不同位置的多个ISS。对相同ISS在不同序列环境中产生的sg RNA进行定量，得出以下结论：(I)转录效率取决于IS在缺陷干扰病毒基因组中的位置，(Ii)下游ISS对上游ISS的转录水平有负面影响，以及(Iii)上游ISS对下游ISS影响很小或没有影响。下游下调上游产生的sg RNA的观察结果解释了为什么较小的sg RNA通常比较大的sg RNA产生的数量更大。我们的数据与冠状病毒转录模型一致，在该模型中ISS减弱了转录。在这些模型中，较大的sg RNA被合成的量较少，因为它们在合成过程中遇到了更多的衰减ISS。
Coronaviruses synthesize a nested set of six to eight subgenomic (sg) mRNAs in infected cells. These mRNAs are produced in different, but constant, molar ratios. It is unclear which factors control the different levels of sg mRNAs. To determine whether the intergenic sequence (IS) involved in sg mRNA synthesis could affect the transcription efficiencies of other ISs and in this way regulate transcription levels, we inserted multiple ISs at different positions into a mouse hepatitis virus defective interfering RNA. Quantitation of the sg RNAs produced by identical ISs in different sequence contexts led to the following conclusions: (i) transcription efficiency depends on the location of the IS in the defective interfering virus genome, (ii) downstream ISs have a negative effect on transcription levels from upstream ISs, and (iii) upstream ISs have little or no effect on downstream ISs. The observation that a downstream IS downregulates the amounts of sg RNA produced by an upstream IS explains why the smaller sg RNAs are, in general, produced in larger quantities than the larger sg RNAs. Our data are consistent with coronavirus transcription models in which ISs attenuate transcription. In these models, larger sg RNAs are synthesized in smaller amounts because they encounter more attenuating ISs during their synthesis.