Figure 8.  Tobacco mosaic virus(TMV) genomic and subgenomic RNAs. (A) The 6400 nucleotide TMV genomic RNA acts as a messenger RNA for the expression of the 126 kDa and 183 kDa replicase-associated proteins. (B) The other genes on TMV RNA are expressed from subgenomic RNAs (sgRNAs) during the replication cycle (see Figure 9 for details). The movement protein (MP), the coat protein (CP), and replicase proteins (RP) have been detected in plants infected with TMV. The 54 kDa-sgRNA accumulates in TMV-infected plants, but thus far the predicted 54 kDa protein has not been detected. The rod-shaped TMV virions are composed of the CP and the genomic RNA (see Figures 6 and 7). (Courtesy K-B.G. Scholthof) BACK