New Insights into the Mechanisms of Aging

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In yeast, aging--marked by an inability to continue replicating--is modulated by a protein called Sir2, which has counterparts, called sirtuins, in nearly every known organism. Normally, yeast Sir2 attaches to repeating DNA sequences to keep them stable. It also doubles as a DNA repairer, migrating to damaged spots on the genome and helping to patch them up. When a yeast cell is young, DNA damage is minimal, and Sir2 can keep up both these roles. But as the cell ages and accumulates more and more DNA damage, Sir2 becomes too busy with repairs to consistently stabilize those volatile repeating sequences. Left unsupervised, the repeats recombine into little extrachromosomal loops of DNA that build up and prevent the cell from reproducing.

In yeast, aging--marked by an inability to continue replicating--is modulated by a protein called Sir2, which has counterparts, called sirtuins, in nearly every known organism. Normally, yeast Sir2 attaches to repeating DNA sequences to keep them stable. It also doubles as a DNA repairer, migrating to damaged spots on the genome and helping to patch them up. When a yeast cell is young, DNA damage is minimal, and Sir2 can keep up both these roles. But as the cell ages and accumulates more and more DNA damage, Sir2 becomes too busy with repairs to consistently stabilize those volatile repeating sequences. Left unsupervised, the repeats recombine into little extrachromosomal loops of DNA that build up and prevent the cell from reproducing.

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http://www.imminst.org/forum/index.php?showtopic=25999&hl=

http://www.imminst.org/forum/index.php?showtopic=25999&hl=