Fig. 1

Chromatin modifications and their associated factors. Transcriptionally permissive chromatin is associated with the absence of DNA methylation (open lollipops) and the presence of H3K4me3/2/1. This mark is established by the MLL and SET family of enzymes and is found in genes actively undergoing transcription. H3K4me3 is found in the promoters, H3K4me2 is found in gene bodies, and H3K4me1 is found in the enhancers of active genes. These marks are erased by demethylases such as LSD1, JARID1, and JARID1b. Transcriptionally repressive chromatin features concurrent cytosine methylation (closed lollipops) and H3K9me3. Cytosine methylation is established by the DNA methyltransferases and erased by the TET family of enzymes. H3K9me3 is established by G9a, SUV39H1, and SETDB1 and erased by JHDM2A. Alternatively, transcriptionally repressive chromatin can contain H3K27me3 and no cytosine methylation (open lollipops). H3K27me3 is established by EZH2, part of the polycomb repressive complex, and is erased by JMJD3 and UTX