[protein synthesis in alkylated bacteriophage T7]

We have studied the toxic effects of alkylating agents with a well characterized model: phage T7. Treatment of bacteriophage T7 with methyl methanesulfonate led to perturbation of phage-specific protein synthesis. Synthesis of class I and II proteins was prolonged, while production of class II and III proteins was delayed. This delay increased for proteins coded by genes located further to the right on the T7 genetic map. In extracts prepared from cells infected by alkylated phage, the specific activity of T7 RNA polymerase was decreased. These results suggest that the toxic action of methyl methanesulfonate is directed towards viral transcription.