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Calorie restriction reduces rDNA recombination independently of rDNA silencing.
- Source :
-
Aging Cell . Dec2009, Vol. 8 Issue 6, p624-632. 9p. 1 Black and White Photograph, 1 Diagram, 1 Chart, 4 Graphs. - Publication Year :
- 2009
-
Abstract
- Calorie restriction (CR) extends lifespan in yeast, worms, flies and mammals, suggesting that it acts via a conserved mechanism. In yeast, activation of the NAD-dependent histone deacetylase, Sir2, by CR is thought to increase silencing at the ribosomal DNA, thereby reducing the recombination-induced generation of extrachromosomal rDNA circles, hence increasing replicative lifespan. Although accumulation of extrachromosomal rDNA circles is specific to yeast aging, it is thought that Sirtuin activation represents a conserved longevity mechanism through which the beneficial effects of CR are mediated in various species. We show here that growing yeast on 0.05 or 0.5% glucose (severe and moderate CR, respectively) does not increase silencing at either sub-telomeric or rDNA loci compared with standard (2% glucose) media. Furthermore, rDNA silencing was unaffected in the hxk2Δ, sch9Δ and tor1Δ genetic mimics of CR, but inhibited by FOB1 deletion. All these interventions extend lifespan in multiple yeast backgrounds, revealing a poor correlation between rDNA silencing and longevity. In contrast, CR and deletion of the FOB1, HXK2, SCH9 and TOR1 genes, all significantly reduced rDNA recombination. This silencing-independent mechanism for suppressing rDNA recombination may therefore contribute to CR-mediated lifespan extension. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CALORIC content of foods
*HISTONE deacetylase
*DNA
*CHROMOSOMES
*GENETICS of aging
Subjects
Details
- Language :
- English
- ISSN :
- 14749718
- Volume :
- 8
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Aging Cell
- Publication Type :
- Academic Journal
- Accession number :
- 45270016
- Full Text :
- https://doi.org/10.1111/j.1474-9726.2009.00514.x