H2B (Ser10) phosphorylation is induced during apoptosis and meiosis in S-cerevisiae

The nucleosome, composed of an octamer of highly conserved histone proteins and associated DNA, is the fundamental unit of eukaryotic chromatin. How arrays of nucleosomes are folded into higher-order structures, and how the dynamics of such compaction are regulated, are questions that remain largely unanswered. Our recent studies demonstrated that phosphorylation of histone H2B is necessary to induce cell death that exhibits phenotypic hallmarks of apoptosis including DNA fragmentation and chromatin condensation in yeast ( serine 10)(1) and in mammalian cells ( serine 14).(2) In this article, we extend these findings by uncovering a role for H2B phosphorylation at serine 10 (Ser10) in another biological event that is associated with dramatic alterations in higher-order chromatin structure, meiosis. Our data show strong staining, indicative of H2B ( Ser10) phosphorylation, during the pachytene stage of yeast meiotic prophase. These data broaden the use of this phosphorylation mark in chromatin remodeling that closely correlates with chromatin compaction. How phosphorylation marks are translated into meaningful downstream events during processes as diverse as apoptosis and meiosis remain a challenge for future studies.