Protein synthesis in cucumber mosaic virus-infected tobacco leaves, pre-infected cells and protoplasts.

Polypeptide synthesis has been investigated in cucumber mosaic virus-infected tobacco by radiolabelling and polyacrylamide gel electrophoresis. In addition to the coat protein polypeptide of molecular weight 27,000, others of higher molecular weight ca. 120,000 to greater than or equal to 160,000 (probably two) and possibly one of ca. 32,000--34,000 were detected in the particulate fractions only. A polypeptide of ca. 53,000--57,000 was particularly evident in leaves systemically infected using a differential temperature treatment. Two polypeptides of low molecular weight, ca. 23,000--24,000 and 21,000, were only observed in pre-infected cells and protoplasts and probably represent coat protein degradation products.