Wang J, Simon A E
Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Virology. 1999 Jun 20;259(1):234-45. doi: 10.1006/viro.1999.9781.
Many plant RNA viruses provide replication and encapsidation functions for one or more satellite RNAs (sat-RNAs) that can modulate the symptoms of the associated helper virus. Sat-RNA C, a virulent sat-RNA associated with turnip crinkle virus (TCV), normally intensifies symptoms but can attenuate symptoms if the TCV coat protein (CP) is replaced with that of cardamine chlorotic fleck carmovirus [Kong et al. (1995) Plant Cell 7, 1625-1634] or if TCV contains an alteration in the CP initiation codon (TCV-CPm) [Kong et al. (1997b) Plant Cell 9, 2051-2063]. To further elucidate the mechanism of symptom attenuation by sat-RNA C, the composition of the CP produced by TCV-CPm (CPCPm) was determined. Our results reveal that CPCPm likely has two additional amino acids at its N-terminus compared with wild-type TCV CP. TCV-CPm produces reduced levels of CP, and this reduction, not the two additional residues at the CP N-terminus, is responsible for symptom attenuation by sat-RNA C.
许多植物RNA病毒为一种或多种卫星RNA（sat-RNA）提供复制和衣壳化功能，这些卫星RNA可调节相关辅助病毒的症状。Sat-RNA C是一种与芜菁皱缩病毒（TCV）相关的毒性卫星RNA，通常会加重症状，但如果将TCV衣壳蛋白（CP）替换为碎米荠褪绿斑点病毒的衣壳蛋白[Kong等人（1995年）《植物细胞》7，1625 - 1634]，或者如果TCV的CP起始密码子发生改变（TCV-CPm）[Kong等人（1997b年）《植物细胞》9，2051 - 2063]，则症状会减轻。为了进一步阐明sat-RNA C减轻症状的机制，我们确定了由TCV-CPm（CPCPm）产生的CP的组成。我们的结果表明，与野生型TCV CP相比，CPCPm在其N端可能多了两个氨基酸。TCV-CPm产生的CP水平降低，而这种降低，而非CP N端的两个额外残基，是sat-RNA C减轻症状的原因。
