Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Cell Cycle. 2011 Aug 15;10(16):2662-8. doi: 10.4161/cc.10.16.17093.
Cytosine methylation is the major epigenetic modification of metazoan DNA. Although there is strong evidence that active DNA demethylation occurs in animal cells, the molecular details of this process are unknown. The recent discovery of the TET protein family (TET1-3) 5-methylcytosine hydroxylases has provided a new entry point to reveal the identity of the long-sought DNA demethylase. Here, we review the recent progress in understanding the function of TET proteins and 5-hydroxymethylcytosine (5hmC) through various biochemical and genomic approaches, the current evidence for a role of 5hmC as an early intermediate in active DNA demethylation and the potential functions of TET proteins and 5hmC beyond active DNA demethylation. We also discuss how future studies can extend our knowledge of this novel epigenetic modification.
胞嘧啶甲基化是真核生物 DNA 的主要表观遗传修饰。尽管有强有力的证据表明,动物细胞中存在活跃的 DNA 去甲基化过程,但这一过程的分子细节尚不清楚。最近发现的 TET 蛋白家族(TET1-3)5-甲基胞嘧啶羟化酶为揭示长期寻求的 DNA 去甲基酶的身份提供了一个新的切入点。在这里,我们通过各种生化和基因组方法,综述了 TET 蛋白和 5-羟甲基胞嘧啶(5hmC)功能的最新研究进展,目前有证据表明 5hmC 是活跃 DNA 去甲基化的早期中间产物,以及 TET 蛋白和 5hmC 在活跃 DNA 去甲基化之外的潜在功能。我们还讨论了未来的研究如何扩展我们对这种新型表观遗传修饰的认识。