PDF(Pubmed)
Abstract：
TET1/2/3 dioxygenases iteratively demethylate 5-methylcytosine, beginning with the formation of 5-hydroxymethylcytosine (5hmC). The post-mitotic brain maintains higher levels of 5hmC than most peripheral tissues, and TET1 ablation studies have underscored the critical role of TET1 in brain physiology. However, deletion of Tet1 precludes the disentangling of the catalytic and non-catalytic functions of TET1. Here, we dissect these functions of TET1 by comparing adult cortex of Tet1 wildtype (Tet1 WT), a novel Tet1 catalytically dead mutant (Tet1 HxD), and Tet1 knockout (Tet1 KO) mice. Using DNA methylation array, we uncover that Tet1 HxD and KO mutations perturb the methylation status of distinct subsets of CpG sites. Gene ontology (GO) analysis on specific differential 5hmC regions indicates that TET1\'s catalytic activity is linked to neuronal-specific functions. RNA-Seq further shows that Tet1 mutations predominantly impact the genes that are associated with alternative splicing. Lastly, we performed High-performance Liquid Chromatography Mass-Spectrometry lipidomics on WT and mutant cortices and uncover accumulation of lysophospholipids lysophosphatidylethanolamine and lysophosphatidylcholine in Tet1 HxD cortex. In summary, we show that Tet1 HxD does not completely phenocopy Tet1 KO, providing evidence that TET1 modulates distinct cortical functions through its catalytic and non-catalytic roles.
摘要：
TET1/2/3双加氧酶迭代去甲基化5-甲基胞嘧啶，从5-羟甲基胞嘧啶（5hmC）的形成开始。有丝分裂后脑的5hmC水平高于大多数外周组织，TET1消融研究强调了TET1在脑生理学中的关键作用。然而,Tet1的缺失排除了TET1的催化和非催化功能的解开。这里,我们通过比较Tet1野生型（Tet1WT）的成年皮质来剖析TET1的这些功能，一种新的Tet1催化死亡突变体（Tet1HxD），和Tet1敲除(Tet1KO)小鼠。使用DNA甲基化阵列，我们发现Tet1HxD和KO突变扰乱了CpG位点不同亚群的甲基化状态.对特定差异5hmC区域的基因本体论（GO）分析表明TET1的催化活性与神经元特异性功能有关。RNA-Seq进一步显示Tet1突变主要影响与可变剪接相关的基因。最后,我们对WT和突变皮质进行了高效液相色谱质谱脂质组学研究,揭示了Tet1HxD皮质中溶血磷脂酰乙醇胺和溶血磷脂酰胆碱的积累.总之,我们表明Tet1HxD不完全表型Tet1KO，提供证据证明TET1通过其催化和非催化作用调节不同的皮质功能。
