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Updated: May 8, 2026
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A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae
Published on: September 17, 2020
Cellular senescence in yeast is regulated by rDNA noncoding transcription
Kimiko Saka1, Satoru Ide, Austen R D Ganley
1Division of Cytogenetics, National Institute of Genetics, The Graduate University for Advanced Studies, Sokendai, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
Current Biology : CB
|September 3, 2013
Summary
Repressing noncoding transcription in the ribosomal RNA gene cluster (rDNA) extends lifespan in yeast. This finding suggests that Sir2 protein maintains lifespan by targeting rDNA, not other genomic regions, revealing a conserved aging pathway.
Area of Science:
- Genetics
- Molecular Biology
- Aging Research
Background:
- Genomic instability is linked to reduced lifespan across species, but the underlying mechanisms remain unclear.
- In yeast (Saccharomyces cerevisiae), the ribosomal RNA gene cluster (rDNA) is prone to genomic instability and is regulated by the SIR2 gene, a known longevity factor.
- Previous research suggested SIR2 influences lifespan by controlling rDNA transcription and stability, but its specific role and the impact of rDNA regulation on lifespan were debated.
Purpose of the Study:
- To investigate whether SIR2's lifespan-extending function is primarily due to its action at the rDNA locus or other genomic sites.
- To determine the direct relationship between repressing noncoding transcription at the rDNA and lifespan extension.
- To clarify the role of rDNA noncoding transcription and stability in the aging process.
Main Methods:
- Utilized a genetically modified yeast strain where the rDNA noncoding promoter was replaced with an inducible promoter system.
- Manipulated the expression of noncoding RNA specifically within the rDNA cluster.
- Assessed the impact of altered rDNA transcription on lifespan and the requirement for SIR2 activity.
Main Results:
- Repression of noncoding transcription originating from the rDNA cluster significantly extended yeast lifespan.
- Lifespan extension was achieved independently of SIR2's canonical function, rendering SIR2 dispensable for this longevity effect.
- These findings pinpoint the repression of E-pro noncoding transcription within the rDNA as the key mechanism by which Sir2 influences lifespan.
Conclusions:
- Sir2 protein primarily maintains lifespan by repressing noncoding transcription at the rDNA locus, not through broader effects on other genomic regions.
- The regulation of rDNA noncoding transcription is a critical determinant of lifespan, suggesting a conserved aging pathway.
- The observed rDNA instability in diverse organisms, including humans, supports the hypothesis that this mechanism is evolutionarily conserved in aging.
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