Mutagenesis in bacteriophage T7. I. Chemically induced mutagenesis

The mutagenesis in phage T7 after MMS-, HNO2-, hydroxylamine-, 5-BUdR-, and 2-AP-treatment in relation to host controlled functions is investigated. There was no dependence of the induction of mutations on the character of the host strains (rec, hcr). A back mutation system (amber system) and a forward mutation system (host range system) have been used. Substances which cause mainly transitions from GC to AT do not lead or only rarely lead to reversions of the amber system; but chemicals producing transitions from AT to GC do so.