Alteration of Scn3a expression is mediated via CpG methylation and MBD2 in mouse hippocampus during postnatal development and seizure condition
Alteration of Scn3a expression is mediated via CpG methylation and MBD2 in mouse hippocampus during postnatal development and seizure condition
复制标题
在出生后发育和癫痫发作期间，小鼠海马中的 CpG 甲基化和 MBD2 介导 Scn3a 表达的改变。
DOI：
10.1016/j.bbagrm.2014.11.004
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发表时间：
2015-01-01
影响因子：
4.7
通讯作者：
Long, Yue-Sheng
中科院分区：
文献类型：
--
作者：
Li, Hai-Jun;Wan, Rui-Ping;Long, Yue-Sheng
钠通道SCN 3A是一种胚胎表达的基因，在癫痫组织中表达增加，被认为有助于癫痫的发生。然而，癫痫状态下SCN 3A表达的调控机制仍不清楚。结果表明，Scn 3a mRNA在小鼠胚胎海马中表达水平较高，随着出生后发育逐渐下降，且在海马中Scn 3a启动子的一个特定CpG位点（-39C）甲基化水平在出生后发育过程中逐渐升高，这与Scn 3a表达的下调相对应。此外，体外甲基化和Scri 3a启动子的-39C > T突变降低了报告基因的表达，表明-39C位点在调节基因表达中起重要作用。然后我们证明了含有-39C的序列是MBD 2结合基序，并且启动子区域的CpG甲基化增加了MBD 2与该基序结合的能力。在小鼠N1 E-115细胞中敲低MBD 2导致-39C甲基化和通过降低Scn 3a启动子活性而下调Scn 3a转录。KA处理10 d后，癫痫小鼠海马Scn 3a和Mbd 2表达上调。在同一时间点，-39C位点被去甲基化，MBD 2与Scn 3a启动子基序结合的能力降低。综上所述，这些发现表明，CpG甲基化和MBD 2参与改变出生后发育和癫痫发作条件下的Scn 3a表达。(C)2014爱思唯尔有限公司版权所有。
Increased expression of sodium channel SCN3A, an embryonic-expressed gene, has been identified in epileptic tissues, which is believed to contribute to the development of epilepsy. However, the regulatory mechanism of SCN3A expression under epileptic condition is still unknown. Here we showed a high level of Scn3a mRNA expression in mouse embryonic hippocampus with gradually decreasing to a low level during the postnatal development and a methylation of a specific CpG site (-39C) in the Scn3a promoter was increased in hippocampus during postnatal development, corresponding to the downregulation of Scn3a expression. Furthermore, in vitro methylation and -39C > T mutation of the Scri3a promoter decreased the reporter gene expression, suggesting an important role of the -39C site in regulating gene expression. We then demonstrated that the sequence containing -39C was a MBD2-binding motif and the CpG methylation of the promoter region increased the capability of MBD2's binding to the motif. Knockdown of MBD2 in mouse N1E-115 cells led to the -39C methylation and the downregulation of Scn3a transcription by decreasing the Scn3a promoter activity. In the hippocampus of seizure mice, the expressions of Scn3a and Mbd2 were upregulated after 10-day KA treatment. At the same time point, the -39C site was demethylated and the capability of MBD2's binding to the Scn3a promoter motif was decreased. Taken together, these findings suggest that CpG methylation and MBD2 are involved in altering Scn3a expression during postnatal development and seizure condition. (C) 2014 Elsevier B.V. All rights reserved.