THE NUCLEOTIDE-SEQUENCE OF COWPEA MOTTLE VIRUS AND ITS ASSIGNMENT TO THE GENUS CARMOVIRUS

The genome of cowpea mottle virus (CPMoV) is a positive ssRNA of 4029 nucleotides with six major open reading frames (ORFs). A non-coding re gion of 34 nucleotides precedes the first AUG. ORF1 encodes a 25 kDa p olypeptide of unknown function and ORF2 encodes a 56 kDa putative RNA replicase. Like other members of carmoviruses, suppression of the ambe r termination codon of ORF1 would produce a readthrough polypeptide of 83 kDa. ORF3 and ORF4 encode two small proteins of 7.8 and 9.8 kDa, r espectively. ORF5 encodes the 40 kDa capsid protein. ORF6 is located w ithin ORF5 but is in a different frame and has no postulated function. CPMoV RNA is blocked at the 5' end and is not polyadenylated at the 3 ' end. Comparison of the physicochemical properties, genomic arrangeme nt, and predicted amino acid sequences with those of other viruses jus tify the assignment of CPMoV to the genus Carmovirus, family Tombusvir idae.