How old mothers can have young offspring

All organisms, even as they themselves age, must give rise to progeny that are young not only chronologically but also biochemically. Now, Hugo Aguilaniu, Thomas Nyström (Göteborg University, Göteborg, Sweden), and colleagues show that budding yeast solves this problem by filtering oxidatively damaged proteins.

The group set out to see if protein carbonylation, an irreversible form of oxidative damage, increased with age in budding yeast. It did, which immediately led to another question. “How,” asks Nyström, “do the daughters come out fresh”?

The daughters do, indeed, emerge with 3.6-fold less damage than their parents, and if the oxidative load is first boosted in the mother the ratio ratchets up to sixfold. This uneven segregation is dependent on the presence of Sir2p. This protein is required to prevent premature yeast aging, and was thought to operate in...