Rochon D M
Agriculture Canada Research Station, Vancouver, BC, Canada.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11153-7. doi: 10.1073/pnas.88.24.11153.
It is generally believed that serial passage at high multiplicity of infection (moi) is required for the generation of defective interfering (DI) particles. High levels of DI RNAs are found associated with persistent infections initiated with laboratory cultures of cucumber necrosis virus (CNV). Two synthetic CNV transcripts that were derived through site-directed mutagenesis of a highly infectious CNV cDNA clone and that do not express the CNV 20-kDa nonstructural protein were found to generate high levels of symptom-attenuating DI RNAs de novo without serial high-moi passage in transcript-inoculated plants. Such de novo generation of DI RNAs did not occur in infections initiated with wild-type transcript until at least eight serial high-moi passages. The observation that a CNV nonstructural protein mutant rapidly generates DI RNA de novo may provide insight into mechanisms that underly DI particle formation in RNA viruses in general.
一般认为，产生缺陷干扰（DI）颗粒需要在高感染复数（moi）下进行连续传代。在由黄瓜坏死病毒（CNV）实验室培养物引发的持续性感染中发现了高水平的DI RNA。通过对高感染性CNV cDNA克隆进行定点诱变获得的两个合成CNV转录本，它们不表达CNV 20 kDa非结构蛋白，发现在转录本接种的植物中无需连续高moi传代就能从头产生高水平的减轻症状的DI RNA。在野生型转录本引发的感染中，直到至少八次连续高moi传代后才出现这种DI RNA的从头产生。CNV非结构蛋白突变体迅速从头产生DI RNA这一观察结果可能为一般RNA病毒中DI颗粒形成的潜在机制提供见解。
