Complete nucleotide sequence of RNA 3 from cucumber mosaic virus (CMV) strain O: comparative study of nucleotide sequences and amino acid sequences among CMV strains O, Q, D and Y.

The complete nucleotide sequence (2217 residues) of RNA 3 of cucumber mosaic virus strain O (CMV-O) was determined. Two open reading frames were identified, encoding a 3A protein (279 amino acid residues) in the 5'-proximal region and a coat protein (218 amino acid residues). The amino acid sequence of the coat protein C terminus was determined directly from purified protein, and confirmed the presence of the coat protein open reading frame in CMV-O RNA 3. Comparison of nucleotide sequences and amino acid sequences of CMV strains O, Q, D and Y indicated the close relationship between these strains. A tRNA-like structure could be adopted by the 3' non-coding region, and this resembled a similar structure in CMV-Q in spite of nucleotide substitutions or deletions.