[Nuclear-mitochondrial interactions in yeasts: mitochondrial mutations compensating the respiration deficiency of...

An approach to the study of nuclear-mitochondrial interactions is reported. A number of spontaneous mutations compensating the respiratory deficiency in nuclear ribosomal suppressor mutants sup1 and sup2 were obtained and analysed. Among mutations analysed, mitochondrial as well as nuclear ones were found. Mitochondrial mutations neutralizing the expression of nuclear mutations were identified using the cytoduction test and their meiotic inheritance. The interaction of these mutations with sup1 and sup2 mutations resulting in restoration of respiratory competence was gene and allele nonspecific. Earlier we proposed that the respiratory deficiency of sup1 and sup2 mutants reflects the participation of sup1 and sup2 proteins not only in cytoplasmic, but also in mitochondrial translation. The interactions revealed open up the possibility of experimental examination of this hypothesis by means of identification of mitochondrial genes bearing compensating mutations.