Cycloheximide-resistance in Chinese hamster ovary cells and human fibroblast cells. Cytogenetic and biochemical characterization.

Cycloheximide(CHM)-resistant mutant Chinese hamster ovary (CHO) and human cells were induced with N-nitrosomethylurea (NMU) and ethyl methanesulfonate (EMS); the mutants were viable and showed unlimited growth in the presence of CHM (7 X 10(-7) M), whereas this concentration inhibits protein synthesis in vivo as well as in vitro. No numerical or structural chromosomal aberrations were found in the mutant cells. In vitro analysis shows that the ribosomes confer resistance against cycloheximide.