DNA Methylation

Systematic analysis of the interactome of modified chromatin

“…Methylation of the C5' position of cytosines, mainly in CpG dinucleotides, is the most prominent and widely studied DNA modification in mammals [45]. Its existence has been proposed more than 100 years ago, and it was detected and unambiguously identified shortly afterwards [46]. In mammals, this modification is deposited by a class of enzymes -DNA methyl transferases (Dnmts), with differing activities.…”

“…On the other hand, regulatory sequences like promoters and enhancers are methylated to a lower level [48]. Sequences with higher than average CpG content are termed CpG islands and are found often unmethylated at promoters of constitutively expressed genes [46]. Methylation is associated with gene silencing, as well as with repression of transposable elements and transcriptional noise in general [49].…”

“…Methylation is associated with gene silencing, as well as with repression of transposable elements and transcriptional noise in general [49]. Interestingly, DNA methylation at CpG island promoters correlates very well with reduced gene expression, however methylation of promoters with low CpG content does not influence transcription significantly [46,50,51]. It is thought that the mechanisms of DNA methylation-regulated gene expression depend on either direct loss of transcription factor binding site on DNA, or on recruitment of proteins binding to methyl-CpG (meCpG)…”

“…KDM enzymes, suggesting involvement in gene silencing [73]. The members of the Kaiso family of meCpG binders contain BTB/POZ motif and their recruitment is mediated by a Krüpel-like C 2 H 2 zink finger [46].…”