DNA methylation pattern
Cytosine DNA methylation is a stable epigenetic mark that is crucial for diverse biological processes, including gene and transposon silencing, imprinting and X chromosome inactivation.
Recent findings in plants and animals have greatly increased our understanding of the pathways used to accurately target, maintain and modify patterns of DNA methylation and have revealed unanticipated mechanistic similarities between these organisms.
Key roles have emerged for small RNAs, proteins with domains that bind methylated DNA and DNA glycosylases in these processes.
DNA methylation patterns are set up early in mammalian development and are then copied during the division of somatic cells.
A new model suggests that the maintenance of DNA methylation relies not only on the recognition of hemimethylated DNA by DNA methyltransferase 1 (DNMT1) but also on the localization of the DNMT3A and DNMT3B enzymes to specific chromatin regions that contain methylated DNA.
See also
DNA methylation.
References
Establishing, maintaining and modifying DNA methylation patterns in plants and animals. Law JA, Jacobsen SE. Nat Rev Genet. 2010 Feb 9;11(3):204-220. PMID: #20142834#
Rethinking how DNA methylation patterns are maintained. Jones PA, Liang G. Nat Rev Genet. 2009 Nov;10(11):805-11. PMID: #19789556#