Wheat germ protein kinase affects the translation of Brome Mosaic virus ribonucleic acid in vitro.

Wheat germ protein kinase inhibits in vitro translation of Brome Mosaic virus (BMV) RNA 1 and 2, without affecting the translation of RNA 4. Inhibition of formation of BMV polypeptides 1a and 2a is due to the arrest of initiation of polypeptide synthesis. It was found that protein kinase inhibits the formation of the 80S initiation complex with BMV RNA 1 and 2, without affecting the formation of the initiation complex with BMV RNA 4. Inhibition of protein synthesis by wheat germ protein kinase is accompanied by the phosphorylation of two ribosome-associated polypeptides, with molecular weights of 32 000 and 76 000, respectively. Both polypeptides are readily dephosphorylated by the enzyme(s) present in the cell-free extract. Their dephosphorylation is accompanied by restoration of the translational capacity of the system.