title: Genetic interactions in the control of mitochondrial functions in Paramecium. I. Interactions between nuclear genes.
abstract: The genetic and physiological properties of two nuclear mutants of Paramecium tetraurelia affecting mitochondrial properties, and first screened as resistant to tetrazolium (TTC) are described. The mutant TTC64-1R is strongly deficient in cytochrome c and the mutant TTC66pR is partially deficient in cytochrome aa3; both mutants display cyanide insensitive respiration in exponential growth phase. In the double mutant TTC64-1R -- TTC66pR/TTC64-1R -- TTC66pR the deficiency in cytochrome aa3 due to the TTC66pR mutation is suppressed. The mutation TTC64-1R does not suppress cytochrome aa3 deficiencies due to mitochondrial mutations, but does interact with another nuclear mutation, cl1, (compatible only with mitochondria deficient in cytochrome oxidase) in such a way that the double mutant TTC64-1R -- cl1/TTC64-1R -- cl1 displays a normal amount of cytochrome aa3. The possible mechanisms and physiological significance of these suppressive effects are discussed.
mesh_terms: D000818:Animals; D003580:Cytochromes / Q000378:metabolism; D004352:Drug Resistance, Microbial; D005796:Genes; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D010247:Paramecium / Q000235:genetics*; D010641:Phenotype; D013778:Tetrazolium Salts / Q000494:pharmacology*
chemical_list: D003580:Cytochromes; D013778:Tetrazolium Salts