Biotechnology and Cell Signaling, University of Strasbourg, CNRS/UMR7242, Illkirch, Strasbourg, France.
Curr Top Dev Biol. 2013;104:47-83. doi: 10.1016/B978-0-12-416027-9.00002-4.
DNA methylation occurs at cytosines, predominantly in the CpG dinucleotide context and is a key epigenetic regulator of embryogenesis and stem-cell differentiation in mammals. The genomic patterns of 5-methylcytosine are extensively reprogrammed during early embryonic development as well as in the germ-cell lineage. Thanks to improvements in high-throughput mapping technologies, it is now possible to characterize the dynamics of this epigenetic mark at the genome scale. DNA methylation plays multiple roles during development and serves to establish long-term gene silencing. In 2009, it was revealed that 5-hydroxymethylcytosine (5hmC) is another prominent cytosine modification catalyzed by the enzymes of the TET family and abundant in certain cell types. 5hmC has been thought to serve as an intermediate in the reaction of DNA demethylation or act as a signal for chromatin factors. Here, we review the current knowledge on the roles of these DNA epigenetic marks in development, epigenetic reprogramming, and pluripotency.
DNA 甲基化发生在胞嘧啶上，主要发生在 CpG 二核苷酸环境中，是哺乳动物胚胎发生和干细胞分化的关键表观遗传调节剂。5-甲基胞嘧啶的基因组模式在早期胚胎发育以及生殖细胞系中广泛重编程。由于高通量作图技术的改进，现在可以在基因组范围内描述这种表观遗传标记的动态。DNA 甲基化在发育过程中发挥多种作用，用于建立长期的基因沉默。2009 年，人们发现 5-羟甲基胞嘧啶（5hmC）是 TET 家族酶催化的另一种重要的胞嘧啶修饰，在某些细胞类型中含量丰富。人们认为 5hmC 可以作为 DNA 去甲基化反应的中间产物，或作为染色质因子的信号。在这里，我们综述了这些 DNA 表观遗传标记在发育、表观遗传重编程和多能性中的作用的最新知识。
