Nuclear suppressors of the mitochondrial mutation oxi1-V25 in Saccharomyces cerevisiae

Summary Ten nuclear suppressors (nam mutations) of the mitochondrial oxi1-V25 ochre mutation are characterized. They restore to some extent the functional form of cytochrome oxidase, as judged by the results of growth tests, cytochrome spectra, cytochrome oxidase activities, and electrophoresis of the products of mitochondrial translation. The nam mutants can suppress some mit ^– mutations mapping in four mitochondrial genes. They act on a number of chain-terminating mit ^– mutations. When grown on glycerol medium some double mutants nam _x-V25 show an increased sensitivity to paromomycin, while the growth of others is stimulated by the drug. The nam mutants are probably omnipotent suppressors resulting from mutations in nuclear gene(s) specifying mitoribosomal protein(s).