The isolation and preliminary characterization of somatic cell mutants resistant to the protein synthesis inhibitor-emetine.

Emetine reversibly inhibits protein synthesis in Chinese hamster ovary (CHO) cells. Stable mutants which are 20-80 fold more resistant to the cytotoxic action of the drug can be isolated in a single step at a frequency of about 2-5 X 10(-7). The frequency of such mutants is increased 30-50 fold by ethyl methane sulphonate mutagenesis, and the spontaneous rate of mutation to emetine resistance as measured by Luria-Delbruck fluctuation analyses is 4.9 X 10(-7) mutations per locus per generation. Protein synthesis in extracts of the mutant cells is resistant to the inhibitory action of the emetine, indicating that the molecular lesion in these cells lies in the protein synthesis machinery.