Structural Basis of Dot1L Stimulation by Histone H2B Lysine 120 Ubiquitination.
The essential histone H3 lysine 79 methyltransferase Dot1L regulates transcription and genomic stability and is deregulated in leukemia. The activity of Dot1L is stimulated by mono-ubiquitination of histone H2B on lysine 120 (H2BK120Ub); however, the detailed mechanism is not understood. We report cryo-EM structures of human Dot1L bound to (1) H2BK120Ub and (2) unmodified nucleosome substrates at 3.5 Å and 4.9 Å, respectively. Comparison of both structures, complemented with biochemical experiments, provides critical insights into the mechanism of Dot1L stimulation by H2BK120Ub. Both structures show Dot1L binding to the same extended surface of the histone octamer. In yeast, this surface is used by silencing proteins involved in heterochromatin formation, explaining the mechanism of their competition with Dot1. These results provide a strong foundation for understanding conserved crosstalk between histone modifications found at actively transcribed genes and offer a general model of how ubiquitin might regulate the activity of chromatin enzymes.
['Valencia-Sánchez|Marco Igor|MI|', 'De Ioannes|Pablo|P|', 'Wang|Miao|M|', 'Vasilyev|Nikita|N|', 'Chen|Ruoyu|R|', 'Nudler|Evgeny|E|', 'Armache|Jean-Paul|JP|', 'Armache|Karim-Jean|KJ|']
D001665:Binding Sites D020285:Cryoelectron Microscopy D015894:Genome, Human D042822:Genomic Instability D006570:Heterochromatin D011495:Histone-Lysine N-Methyltransferase D006657:Histones D006801:Humans D007938:Leukemia D008239:Lysine D009687:Nuclear Proteins D009707:Nucleosomes D011485:Protein Binding D011487:Protein Conformation D029701:Saccharomyces cerevisiae Proteins D014158:Transcription, Genetic D054875:Ubiquitination
structure ubiquitin cryo-EM nucleosome Dot1 histone modifications chromatin H3K79 histone cross-talk methylation