title: Macromolecular synthesis and energy level in a mitochondrial conditional yeast mutant, tsm-8.
abstract: Mitochondrial DNA, protein and ATP syntheses persist at non-permissive temperature (35 degrees C) in the mitochondrial, conditionally rho- petites forming yeast mutant, tsm8. Protein and ATP syntheses, however, are diminished during prolonged incubation at 35 degrees C in non-fermentable substrate. Mitochondrial RNA synthesis decreases rapidly to a residual constant level of about 10% of the initial value after the shift to 35 degrees C. The decrease is reversed by returning to permissive conditions. Evidence is presented that this temperature-induced decrease in mitochondrial transcription rate is effected by a mutationally altered regulatory process rather than by temperature sensitivity of mitochondrial RNA polymerase. It is concluded that rho- petite formation in mutant tsm8 is not effected by complete inhibition of macromolecular and ATP syntheses but is correlated with a reduction in mitochondrial transcription.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D002455:Cell Division; D004272:DNA, Mitochondrial / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000096:biosynthesis*; D007700:Kinetics; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D012313:RNA / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013696:Temperature
chemical_list: D004272:DNA, Mitochondrial; D005656:Fungal Proteins; D012313:RNA; D000255:Adenosine Triphosphate