Fig. 2.
H3K79 methylation in telomere silencing: Spreading of SIR complex from heterochromatin to euchromatin is blocked by combined action of H4K16 acetylation and H3K79 methylation. Sas2 acetylates H4K16, which prevents Sir3 from binding to the H4 tail and stimulates Dot1 binding to the H4 N-terminal tail. Methylation of H3K79 by Dot1 further blocks Sir3 binding to the H3K79 region.