A Mutation in the Yeast Mitochondrial Ribosomal Protein RmI2p Is Associated with a Defect in Catalase Gene Expression

摘要

Yeast strains containing a new temperature sensitive allele of the RML2 gene, encoding a component of the large subunit of the mitochondrial ribosome, display mormal growth on acetate, slowed growth on glycerol and an inability to grow on oleicecacid. These cells, denoted rml2(fat21), have an apparent inability to induce peroxisomal function, as evideced by a deficiency in oleic acid induction of betaoxidation. However, the oleic acid regulation of genes encoding core enzymes of peroxisomal beta-oxidation is normal. In contrast, up-regulation of CTA1 (catalase) mRNA expression and enzyme activity is interrupted. Upon comparison of the induction requirements of catalase and the genes of beta-oxidation, we hypothesized that the rml2(fat21) mutation alters the activity of the transcription factor Adrlp.In support of this hypothesis, over-expression of ADR1 in rml2(fat21) cells restores CTA1 induction. Several assays of mitochondria from rml2(fat21) strains suggest normal mitochondria function. Thus the modulation of Adrlp-associated gene regulation is not due to overt mitochondrial dysfunction