A temperature-sensitive strain of tobacco mosaic virus defective in cell-to-cell movement generates an altered viral-coded protein.

An analysis has been made of the proteins synthesized in vivo and in vitro from two closely related tomato strains of tobacco mosaic virus, one of which is defective in cell-to-cell movement at a restrictive temperature [Nishiguchi et al. (1978). J. Gen. Virol. 39, 53-61]. The coat proteins of the two strains (L, and the temperature-sensitive LS-1) are identical as revealed by two-dimensional tryptic peptide maps prepared from proteins synthesized in vivo. Peptide maps of the 30,000, 130,000, and 165,000 Mr viral RNA in vitro translational products revealed a slight difference only in the 30,000 Mr polypeptides of the two strains, implicating this polypeptide as a factor mediating cell-to-cell movement of virus in the leaf.