RNA polymerase III (Pol III) produces essential components of the biosynthetic machinery and therefore its activity is tightly coupled with the cell growth and metabolism. In the yeast Saccharomyces cerevisiae, Maf1 is the only known global and direct Pol III transcription repressor which mediates numerous stress signals. Here we demonstrate that transcription regulation by Maf1 is not limited to stress but is important for the switch between fermentation and respiration. Under respiratory conditions Maf1 is activated by dephosphorylation and imported into the nucleus. Transition from a nonfermentable carbon source to glucose induces Maf1 phosphorylation and its relocation to the cytoplasm. The absence of Maf1-mediated control of tRNA synthesis impairs cell viability in nonfermentable carbon sources. The respiratory phenotype of maf1-Delta allowed genetic suppression studies toward dissection of the mechanism of Maf1 action on the Pol III transcription apparatus. Moreover, in cells grown in a nonfermentable carbon source, Maf1 regulates the levels of different tRNAs to various extent. This different regulation may contribute to the physiological role of Maf1.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|