Cycloheximide insensitive nuclear protein synthesis partially suppressed by chloramphenicol: Some possible implications in the evolution of eukaryotes

Abstract

1. 1. Cycloheximide-resistant nuclear protein synthesis that is almost completely suppressed by puromycin and partially inhibited by chloramphenicol can be demonstrated with the use of a mutant Chinese hamster ovary cell line exhibiting a temperature-sensitive defect in cytoplasmic non-mitochondrial protein synthesis. 2. 2. For a number of reasons, mitochondria are unlikely to be the source of chloramphenicol-sensitive cycloheximide-resistant nuclear protein synthesis. 3. 3. The existence of nuclear protein synthesis that is unaffected by cycloheximide and partially inhibited by chloramphenicol raises a number of questions about the evolution of eukaryotic cell nuclei.