Examining Changes To Chromatin During Chronological Aging In Budding Yeast

Histone proteins, which compact DNA, have post-translational modifications (PTMs) that dictate chromatin structure; controlling accessibility of transcription factors and protecting DNA from damage. The purpose of this study was to examine changes in histone PTMs that accompany the aging process in yeast. Specifically, we examined histone PTMs in two populations within chronologically aged yeast, the nonquiescent (NQ) and quiescent (Q) cells, which are thought to have varying levels of cellular damage and different reproductive capacities. Similar histone PTMs were found in NQ and Q populations, but the levels of modification showed differences. Interestingly, although Q cells have enhanced viability and reproductive capacity, they showed greater sensitivity to DNA damaging agents, but more resistance to oxidative damage. Further investigation is aimed at understanding the roles of histone PTMs in protecting the genome from these diverse forms of damage during aging. Supported by Tufts University startup funds to S.M.F.