Stage- and site-specific DNA demethylation during neural cell development from embryonic stem cells
Stage- and site-specific DNA demethylation during neural cell development from embryonic stem cells
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DOI：
10.1111/j.1471-4159.2005.03031.x
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发表时间：
2005-04-01
影响因子：
4.7
通讯作者：
Taga, T
中科院分区：
文献类型：
--
作者：
Shimozaki, K;Namihira, M;Taga, T
转录因子 STAT3 的激活对于神经发育过程中星形胶质细胞的分化非常重要。胶质纤维酸性蛋白（GFAP）基因（星形胶质细胞的标记物）启动子中 STAT3 结合位点的甲基 CpG 二核苷酸去甲基化，先前已被证明是神经祖细胞在大脑发育过程中响应星形信号而表达该基因的关键线索。在本研究中，我们分析了小鼠胚胎干（ES）细胞体外神经细胞发育过程中 GFAP 基因启动子中 STAT3 结合位点的甲基化状态。 GFAP 基因启动子中 STAT3 结合位点的 CpG 二核苷酸在未分化的多能 ES 细胞中表现出高发生率的胞苷甲基化。这种特定胞苷的甲基化发生率在 ES 细胞衍生的神经外胚层样细胞中保持较高的发生率，但当神经谱系细胞响应 STAT3 激活信号而能够表达 GFAP 时，它就会发生去甲基化。相比之下，在相同 ES 细胞产生的非神经细胞中，CpG 位点的高甲基化得以维持。在体外培养过程中，在原代胚胎神经上皮细胞中也观察到 GFAP 基因启动子中 STAT3 结合位点的进行性去甲基化，而非神经细胞即使在培养后仍保持该位点的高甲基化。总而言之，这些结果表明，当来自多能细胞的神经祖细胞分化为能够产生星形胶质细胞的神经谱系时，星形胶质细胞基因特异性胞苷去甲基化被编程。
Activation of the transcription factor STAT3 is important for astrocyte differentiation during neural development. Demethylation of the methyl-CpG dinucleotide in the STAT3 binding site in the promoter of the glial fibrillary acidic protein (GFAP) gene, a marker for astrocytes, was previously shown to be a crucial cue for neural progenitors to express this gene in response to astrogenic signals during brain development. In this study, we analyzed the methylation status of the STAT3 binding site in the GFAP gene promoter during neural cell development from mouse embryonic stem (ES) cells in vitro. The CpG dinucleotide in the STAT3 binding site in the GFAP gene promoter exhibited a high incidence of cytidine-methylation in undifferentiated pluripotent ES cells. The high incidence of methylation of this particular cytidine was maintained in ES cell-derived neuroectoderm-like cells, but it underwent demethylation when the neural lineage cells became competent to express GFAP in response to a STAT3 activation signal. In contrast, hypermethylation of the CpG site was maintained in non-neural cells generated from the same ES cells. Progressive demethylation of the STAT3 binding site in the GFAP gene promoter was also observed in primary embryonic neuroepithelial cells during in vitro culture, whereas non-neural cells maintained hypermethylation of this site even after culture. Taken together, these results demonstrate that the astrocyte gene-specific cytidine-demethylation is programmed when neural progenitors from pluripotent cells are committed to a neural lineage that is capable of producing astrocytes.