Regulation of the Dot1 histone H3K79 methyltransferase by histone H4K16 acetylation

Cross-talk between histone modifications Histone modifications play pivotal roles within the intricate protein networks that underlie transcription and gene silencing in eukaryotic genomes. The enzymes that deposit them undergo spatiotemporal fine-tuning of their catalytic activity; one example is trans-histone cross-talk, in which one histone modification activates an enzyme responsible for another histone modification. Valencia-Sánchez et al. show that histone H4 lysine 16 acetylation (H4K16ac), a hallmark of decondensed, transcriptionally permissive chromatin, directly stimulates the Dot1 histone H3 lysine 79 methyltransferase. Structural, biochemical, and cellular data explain Dot1's regulation by H4K16ac and show how it coordinates with a second positive regulator of Dot1, histone H2B ubiquitination. Science , this issue p. eabc6663