title: Active DNA demethylation and DNA repair.
abstract: DNA methylation on cytosine is an epigenetic modification and is essential for gene regulation and genome stability in vertebrates. Traditionally DNA methylation was considered as the most stable of all heritable epigenetic marks. However, it has become clear that DNA methylation is reversible by enzymatic "active" DNA demethylation, with examples in plant cells, animal development and immune cells. It emerges that "pruning" of methylated cytosines by active DNA demethylation is an important determinant for the DNA methylation signature of a cell. Work in plants and animals shows that demethylation occurs by base excision and nucleotide excision repair. Far from merely protecting genomic integrity from environmental insult, DNA repair is therefore at the heart of an epigenetic activation process.
authors.affiliation: Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany. Niehrs@DKFZ-Heidelberg.de
authors.forename: Christof
authors.initials: C
authors.lastname: Niehrs
mesh_terms: D000818:Animals; D019175:DNA Methylation; D004260:DNA Repair; D005786:Gene Expression Regulation; D006801:Humans