Wang J, Simon A E
Department of Biochemistry and Molecular Biology and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Virol. 2000 Jul;74(14):6528-37. doi: 10.1128/jvi.74.14.6528-6537.2000.
Many plant RNA viruses are associated with one or more subviral RNAs. Two subviral RNAs, satellite RNA C (satC) and defective interfering RNA G (diG) intensify the symptoms of their helper, turnip crinkle virus (TCV). However, when the coat protein (CP) of TCV was replaced with that of the related Cardamine chlorotic fleck virus (CCFV), both subviral RNAs attenuated symptoms of the hybrid virus TCV-CP(CCFV). In contrast, when the translation initiation codon of the TCV CP was altered to ACG and reduced levels of CP were synthesized, satC attenuated symptoms while diG neither intensified nor attenuated symptoms. The determinants for this differential symptom modulation were previously localized to the 3'-terminal 100 bases of the subviral RNAs, which contain six positional differences (Q. Kong, J.-W. Oh, C. D. Carpenter, and A. E. Simon, Virology 238:478-485, 1997). In the current study, we have determined that certain sequences within the 3'-terminal stem-loop structures of satC and diG, which also serve as promoters for complementary strand synthesis, are critical for symptom modulation. Furthermore, the ability to attenuate symptoms was correlated with weakened binding of TCV CP to the hairpin structure.
许多植物RNA病毒与一种或多种亚病毒RNA相关。两种亚病毒RNA，即卫星RNA C（satC）和缺陷干扰RNA G（diG），会加重其辅助病毒芜菁皱缩病毒（TCV）的症状。然而，当用相关的碎米荠褪绿斑点病毒（CCFV）的衣壳蛋白（CP）替换TCV的衣壳蛋白时，两种亚病毒RNA都减轻了杂种病毒TCV-CP(CCFV)的症状。相反，当将TCV CP的翻译起始密码子改为ACG并合成水平降低的CP时，satC减轻了症状，而diG既没有加重也没有减轻症状。这种差异症状调节的决定因素先前已定位到亚病毒RNA的3'末端100个碱基，其中包含六个位置差异（Q. Kong、J.-W. Oh、C. D. Carpenter和A. E. Simon，《病毒学》238:478-485，1997）。在本研究中，我们确定satC和diG的3'末端茎环结构内的某些序列（这些序列也作为互补链合成的启动子）对于症状调节至关重要。此外，减轻症状的能力与TCV CP与发夹结构的结合减弱相关。
