In eukaryotes, the ribosomal DNA (rDNA) consists of long tandem repeat arrays. These repeated genes are unstable because homologous recombination between them results in copy number loss. To maintain high copy numbers, yeast has an amplification system that works through a pathway involving the replication fork barrier site and unequal sister chromatid recombination. In this study, we show that an active replication origin is essential for amplification, and the amplification rate correlates with origin activity. Moreover, origin activity affects the levels of extrachromosomal rDNA circles (ERC) that are thought to promote aging. Surprisingly, we found that reduction in ERC level results in shorter life span. We instead show that life span correlates with rDNA stability, which is preferentially reduced in mother cells, and that episomes can induce rDNA instability. These data support a model in which rDNA instability itself is a cause of aging in yeast.
|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||Reference||Annotation Extension|
|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||Conditions||Strain||Source||Reference|