Exploration of hydroxymethylation in Kagami-Ogata syndrome caused by hypermethylation of imprinting control regions.
Exploration of hydroxymethylation in Kagami-Ogata syndrome caused by hypermethylation of imprinting control regions.
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DOI：
10.1186/s13148-015-0124-y
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发表时间：
2015
影响因子：
5.7
通讯作者：
Yamazawa K
中科院分区：
文献类型：
--
作者：
Matsubara K;Kagami M;Nakabayashi K;Hata K;Fukami M;Ogata T;Yamazawa K
5-羟甲基胞嘧啶（5 hmC）是由5-甲基胞嘧啶（5 mC）经10 - 11易位（泰特）酶转化而成的，被认为是DNA去甲基化途径的中间产物，被认为是DNA的“第六碱基”。尽管如此，它仍然是有待解决的5 hmC是如何与人类印记疾病的发展。在这方面，常规的亚硫酸氢盐（BS）处理不能区分5 hmC和5 mC。因此，假设BS转化衍生的“高甲基化”在印迹控制区（ICR），这可能会导致印迹障碍，实际上是由于过度增加的5 hmC以及5 mC的水平。为了验证这一假设，我们应用新开发的氧化BS（oxBS）治疗来检测来自Kagami-Ogata综合征（KOS 14）患者的血液样本中的5 hmC，所述Kagami-Ogata综合征（KOS 14）患者是由两个差异甲基化区域（DMR）的表突变（高甲基化）引起的，所述DMR充当ICR，即IG-DMR和MEG 3-DMR。oxBS与焦磷酸测序显示，在来自KOS 14患者的血液样品中，在高甲基化的IG-DMR和MEG 3-DMR处存在少量的5 hmC。oxBS与全基因组甲基化阵列显示，5 hmC的总体水平非常低，在KOS 14患者和正常对照的血液样品中具有相似的分布模式。我们还证实了在正常对照的脑样品中存在大量的5 hmC。5 hmC不是异常高甲基化ICR或全球水平的主要成分，至少在KOS 14患者的血液中是如此。由于大脑样本含有大量的5 hmC，KOS 14患者的神经组织是有希望的候选者，用于分析阐明5 hmC在神经发育背景中的作用。本文的在线版本（doi：10.1186/s13148-015-0124-y）包含补充材料，可供授权用户使用。
5-Hydroxymethylcytosine (5hmC), converted from 5-methylcytosine (5mC) by ten-eleven translocation (Tet) enzymes, has recently drawn attention as the “sixth base” of DNA since it is considered an intermediate of the demethylation pathway. Nonetheless, it remains to be addressed how 5hmC is linked to the development of human imprinting disorders. In this regard, conventional bisulfite (BS) treatment is unable to differentiate 5hmC from 5mC. It is thus hypothesized that BS conversion-derived “hypermethylation” at imprinting control regions (ICRs), which may cause imprinting disorders, would in fact be attributable to excessively increased levels of 5hmC as well as 5mC. To test this hypothesis, we applied the newly developed oxidative BS (oxBS) treatment to detect 5hmC in blood samples from Kagami-Ogata syndrome (KOS14) patients caused by an epimutation (hypermethylation) of two differentially methylated regions (DMRs) functioning as ICRs, namely, IG-DMR and MEG3-DMR. oxBS with pyrosequencing revealed that there were few amounts of 5hmC at the hypermethylated IG-DMR and MEG3-DMR in blood samples from KOS14 patients. oxBS with genome-wide methylation array demonstrated that global levels of 5hmC were very low with similar distribution patterns in blood samples from KOS14 patients and normal controls. We also confirmed the presence of large amounts of 5hmC in the brain sample from a normal control. 5hmC is not a major component in abnormally hypermethylated ICRs or at a global level, at least in blood from KOS14 patients. As the brain sample contained large amounts of 5hmC, the neural tissues of KOS14 patients are promising candidates for analysis in elucidating the role of 5hmC in the neurodevelopmental context. The online version of this article (doi:10.1186/s13148-015-0124-y) contains supplementary material, which is available to authorized users.