The Mammalian Epigenome Bradley E. Bernstein, Alexander Meissner, Eric S. Lander  Cell  Volume 128, Issue 4, Pages 669-681 (February 2007) DOI: 10.1016/j.cell.2007.01.033 Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 1 Cytosine and Histone Methylation Cytosine methylation is the only known covalent modification of DNA in mammals. In contrast, histones are subject to hundreds of modifications, including acetylation, methylation, phosphorylation, and ubiquitination. (A) illustrates the structures and effects of cytosine methylation (repressive/red) and two histone marks: H3K27 methylation (repressive/red) and H3K4 methylation (activating/green). (B) illustrates the diversity of histone H3 modifications. Cell 2007 128, 669-681DOI: (10.1016/j.cell.2007.01.033) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 2 The Epigenome Is a Complete Description of “Heritable” Modifications to DNA and Histone Proteins as They Occur across the Genome (A) The epigenome's makeup within a given cell is a function of genetic determinants, lineage-specific cues, and environment. The different chemical changes interact to form a complex regulatory network that modulates chromatin structure and genome function (Margueron et al., 2005). (B) Several lines of evidence suggest that the epigenome of pluripotent embryonic stem cells is uniquely plastic (Meshorer et al., 2006; Vire et al., 2006; and references in text). Cell 2007 128, 669-681DOI: (10.1016/j.cell.2007.01.033) Copyright © 2007 Elsevier Inc. Terms and Conditions