Symptom attenuation by a satellite RNA in vivo is dependent on reduced levels of virus coat protein.
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.
Wang
J
J
Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Simon
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D001483:Base Sequence; D002213:Capsid / Q000502:physiology*; D008969:Molecular Sequence Data; D010942:Plant Viruses / Q000502:physiology*; D019244:RNA, Satellite / Q000502:physiology*; D012367:RNA, Viral / Q000502:physiology*; D014779:Virus Replication / Q000235:genetics
D019244:RNA, Satellite; D012367:RNA, Viral