MOLECULAR EVIDENCE FROM 3'-TERMINUS SEQUENCE-ANALYSIS THAT TOBACCO VEIN-BANDING MOSAIC-VIRUS IS A DISTINCT MEMBER OF THE POTYVIRUS GROUP

The 3'-terminal 1902 nucleotides of the tobacco vein-banding mosaic virus (TVBMV) were cloned and sequenced. The sequence contains a large open reading frame of 572 amino acid residues followed by a non-coding region of 183 nucleotides which terminates in a polyadenylate tract. The TVBMV coat protein is processed from a larger polyprotein by cleavage at a Gln/Gly dipeptide, which is followed closely by the aphid transmission DAG triplet. Translation of the nucleotide sequence yielded a protein of 271 amino acid residues with a calculated M(r) of 30347. The amino acid and nucleotide sequences of the TVBMV coat protein and 3' non-coding region were compared to 33-35 other virus sequences. Percent sequence identity of the amino acid and nucleotide sequences were in the range expected from comparison of distinct viruses. Phylogenetic analyses were also performed to determine the relationship of TVBMV to other well-characterized viruses. These studies indicate that TVBMV should be regarded as a distinct member of the potyvirus group.