Dissecting the dynamic changes of 5-hydroxymethylcytosine in T cell development and differentiation [RNA-Seq]. Mus musculus

The discovery of TET proteins, enzymes that oxidize 5-methylcytosine (5mC) in DNA, has revealed novel mechanisms for the regulation of DNA methylation. We have mapped 5-hydroxymethylcytosine (5hmC) at different stages of T cell development in the thymus and T cell differentiation in the periphery. We show that 5hmC is enriched in the gene body of highly expressed genes at all developmental stages, and that its presence correlates positively with gene expression. Further emphasizing the connection with gene expression, we find that 5hmC is enriched in active thymus-specific enhancers, and that genes encoding key transcriptional regulators display high intragenic 5hmC levels in precursor cells at those developmental stages where they exert a positive effect. Our data constitute a valuable resource that will facilitate detailed analysis of the role of 5hmC in T cell development and differentiation. Overall design: Transcriptome profiling of naïve CD4 and CD8 cells

TET蛋白（TET proteins）——可氧化DNA中5-甲基胞嘧啶（5-methylcytosine，5mC）的酶类——的发现，揭示了DNA甲基化调控的全新机制。本研究对胸腺内T细胞发育及外周T细胞分化的不同阶段的5-羟甲基胞嘧啶（5-hydroxymethylcytosine，5hmC）进行了图谱绘制。结果显示，在所有发育阶段中，5hmC均富集于高表达基因的基因本体区域，且其丰度与基因表达水平呈正相关。进一步验证其与基因表达的关联：我们观察到5hmC在活跃的胸腺特异性增强子中富集，且编码关键转录调控因子的基因，在其发挥正向调控作用的发育阶段前体细胞中，呈现出较高的基因内5hmC水平。本研究数据是一项宝贵的资源，将为深入解析5hmC在T细胞发育与分化中的作用提供助力。整体实验设计：初始型CD4与CD8 T细胞的转录组分析。