FIGURE 1.

H3 sequence and posttranslational modifications. Graphic representation of human H3.1 primary sequence and secondary structures. Inset boxes denote areas that differ between the H3.1 and H3.3 variants, with sequence differences highlighted in yellow. Residues that are subject to acetylation, methylation or phosphorylation are denoted as such (Paulson and Taylor, 1982; Bernstein et al., 2005; Wang et al., 2008; Zhao and Garcia, 2015). The number of triangles marks the maximum number of methyl marks that can be installed. Select key marks that generally correlate with transcriptional repression (red) and activation (green), and that are discussed in the review, are also noted (Rea et al., 2000; Bernstein et al., 2005; Hake et al., 2006; Wang et al., 2008; Margueron et al., 2009). The phosphorylation of residue 31 is exclusive to H3.3 (Hake et al., 2005).