Other Free Encyclopedias » Medicine Encyclopedia » Aging Healthy - Part 2 » Genetics: Gene Expression - Genes And Noncoding Dna, Flow Of Genetic Information, Control Of Gene Expression, Gene Expression And Aging

Genetics: Gene Expression - Gene Expression And Life Span

age aging aging sir2 yeast silencing

No single change in gene expression has yet been shown to be responsible for limiting or extending the life span of an organism (or even a tissue, for that matter). However, manipulation of general regulators of gene expression has been shown to alter life span, at least in model organisms. Perhaps the best example of this is the SIR2 protein, which is conserved from yeast to mammals and is responsible for the heterochromatic silencing of genes. In yeast, inactivation of the SIR2 gene results in defective gene silencing, increased illegitimate recombination at the repetitive loci that encode rRNAs, and a shortening of life span. Conversely, an additional copy of the yeast SIR2 gene, which presumably results in more efficient silencing and suppression of recombination, extends yeast life span. Of greater relevance to complex eukaryotes, an additional copy of the SIR2 gene in the model organism Caenorhabditis elegans, a multicellular nematode, also extends life span. SIR2 requires NAD (nicotinamide adenine dinucleotide) as a cofactor. Thus, SIR2 may act to coordinate energy utilization, recombination, and control of gene expression, all of which may strongly influence life span.



FINKEL, T., and HOLBROOK, N. J. "Oxidants, Oxidative Stress, and the Biology of Ageing." Nature 408 (2000): 239–247.

GUARENTE, L. "Sir2 Links Chromatin Silencing, Metabolism, and Aging." Genes and Development 14 (2000): 1021–1026.

HAN, E.; HILSENBECK, S. G.; RICHARDSON, A.; and NELSON, J. F. "cDNA Expression Arrays Reveal Incomplete Reversal of Age-Related Changes in Gene Expression by Calorie Restriction." Mechanisms of Ageing and Development 115 (2000): 157–174.

HEDARI, A. R.; YOU, S.; TAKAHASHI, R.; GUTSMANN-CONRAD, A.; SARGE, K. D.; and RICHARDSON, A. "Age-Related Alterations in the Activation of Heat Shock Transcription Factor 1 in Rat Hepatocytes." Experimental Cell Research 256 (2000): 83–93.

LEE, C.; KLOPP, R. C.; WEINDRUCH, R.; and PROLLA, T. A. "Gene Expression Profile of Aging and Its Retardation by Caloric Restriction." Science 285 (1999): 1390–1393.

PAPACONSTANTINOU, J. "Unifying Model of the Programmed and Stochastic Theories for Aging. The Stress Response Genes, Signal Transduction-Redox Pathways, and Aging." Annals of the New York Academy of Sciences 719 (1994): 195–211.

RATTAN, S. I. "Synthesis, Modifications, and Turnover of Proteins During Aging." Experimental Gerontology 31 (1996): 33–47.

ROY, A. K. "Transcription Factors and Aging." Molecular Medicine 3 (1997): 496–504.

VIJG, J. "Profiling Aging by Gene Arrays." Mechanisms in Aging and Development 112 (1999): 1–4.

VILLEPONTEAU, B. "The Heterochromatin Loss Model of Aging." Experimental Gerontology 32 (1997): 383–394.

[back] Genetics: Gene Expression - Gene Expression And Aging

User Comments

The following comments are not guaranteed to be that of a trained medical professional. Please consult your physician for advice.

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or