Cell volume as a factor limiting the replicative lifespan of the yeast Saccharomyces cerevisiae

The number of cell divisions of the yeast Saccharomyces cerevisiae is limited, referred to as replicative lifespan of this organism and believed to be due to aging mechanisms similar to those of mammalian cells. We demonstrate, using three pairs of isogenic yeast strains (standard and a mutant deficient in an antioxidant defense protein) that although the lifespan differs significantly, the final volume attained after the last division is similar within each pair of strains. In a population, cells cease to bud after various number of cell cycles but attaining a similar final volume. These results indicate that the increase in the mother cell volume, intrinsic to the asymmetric cell division in S. cerevisiae, may be the main mechanism limiting the reproductive capacity of in this organism.