Increased dosage of a sir-2 gene extends lifespan in Caenorhabditis elegans.
In Caenorhabditis elegans, mutations that reduce the activity of an insulin-like receptor (daf-2) or a phosphatidylinositol-3-OH kinase (age-1) favour entry into the dauer state during larval development and extend lifespan in adults. Downregulation of this pathway activates a forkhead transcription factor (daf-16), which may regulate targets that promote dauer formation in larvae and stress resistance and longevity in adults. In yeast, the SIR2 gene determines the lifespan of mother cells, and adding an extra copy of SIR2 extends lifespan. Sir2 mediates chromatin silencing through a histone deacetylase activity that depends on NAD (nicotinamide adenine dinucleotide) as a cofactor. We have surveyed the lifespan of C. elegans strains containing duplications of chromosomal regions. Here we report that a duplication containing sir-2.1-the C. elegans gene most homologous to yeast SIR2-confers a lifespan that is extended by up to 50%. Genetic analysis indicates that the sir-2.1 transgene functions upstream of daf-16 in the insulin-like signalling pathway. Our findings suggest that Sir2 proteins may couple longevity to nutrient availability in many eukaryotic organisms.
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
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Tissenbaum
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D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D002874:Chromosome Mapping; D005260:Female; D051858:Forkhead Transcription Factors; D018628:Gene Dosage; D020440:Gene Duplication; D005800:Genes, Fungal; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008136:Longevity / Q000235:genetics; D008297:Male; D015398:Signal Transduction; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D051858:Forkhead Transcription Factors; D015801:Helminth Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators; D014157:Transcription Factors; C108831:daf-16 protein, C elegans; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases