[Cucumber mosaic virus cDNA vector expressed foreign genes in tobacco cells]

Full-length cDNA of SD strain CMV (SD-CMV) RNA 3 was cloned and sequenced. An Nsi I site was created at the sequence around the start codon of coat protein (CP) gene and a replacement cassette was constructed. The CP gene was replaced by green fluorescent protein (GFP) gene, beta-glucuronidase (GUS) gene or mouse dihydrofolate reductase (DHFR) gene, respectively. The cDNAs of Fny-CMV RNAs 1 and 2 and the chimeric SD-CMV RNA 3 were cloned between the 35S promoter and terminator separately. Tobacco protoplasts transfected with the CMV cDNA vectors expressed the three reporters, implying that CMV could be used as an expression vector.