Dynamic methylation and expression of Oct4 in early neural stem cells
Dynamic methylation and expression of Oct4 in early neural stem cells
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DOI：
10.1111/j.1469-7580.2010.01269.x
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发表时间：
2010-09-01
影响因子：
2.4
通讯作者：
Scotting, Paul J.
中科院分区：
文献类型：
--
作者：
Lee, Shih-Han;Jeyapalan, Jennie N.;Scotting, Paul J.
神经干细胞是具有广泛但有限分化潜能的多能组织特异性干细胞群。然而，最近的研究表明，多能性基因Oct 4的过度表达足以启动一个过程，通过该过程，这些细胞可以形成具有与胚胎干细胞相同的广泛潜力的“诱导多能干细胞”（iPS细胞）。这导致我们检查Oct 4在内源性神经干细胞中的表达，因为关于其在体内神经干细胞中表达的数据是矛盾和不完整的。因此，在这项研究中，我们分析了Oct 4和其他与多能性相关的基因在小鼠CNS和体外培养的神经干细胞发育过程中的表达。我们发现Oct 4在E8.5时仍在CNS中表达，但这种表达迅速下降，直到E15.5检测不到。这种下降与Oct 4启动子和近端增强子的逐渐甲基化一致。免疫染色表明，Oct 4蛋白主要是细胞质的位置。我们还发现，所有年龄段的神经干细胞都表达多能性相关基因Sox 2、c-Myc、Klf 4和Nanog。这些数据为早期神经上皮细胞在不同发育阶段的不同行为提供了解释。这些基因的表达也提供了为什么单独的Oct 4足以在后期诱导神经干细胞中iPS形成的指示。
Neural stem cells are a multipotent population of tissue-specific stem cells with a broad but limited differentiation potential. However, recent studies have shown that over-expression of the pluripotency gene, Oct4, alone is sufficient to initiate a process by which these can form 'induced pluripotent stem cells' (iPS cells) with the same broad potential as embryonic stem cells. This led us to examine the expression of Oct4 in endogenous neural stem cells, as data regarding its expression in neural stem cells in vivo are contradictory and incomplete. In this study we have therefore analysed the expression of Oct4 and other genes associated with pluripotency throughout development of the mouse CNS and in neural stem cells grown in vitro. We find that Oct4 is still expressed in the CNS by E8.5, but that this expression declines rapidly until it is undetectable by E15.5. This decline is coincident with the gradual methylation of the Oct4 promoter and proximal enhancer. Immunostaining suggests that the Oct4 protein is predominantly cytoplasmic in location. We also found that neural stem cells from all ages expressed the pluripotency associated genes, Sox2, c-Myc, Klf4 and Nanog. These data provide an explanation for the varying behaviour of cells from the early neuroepithelium at different stages of development. The expression of these genes also provides an indication of why Oct4 alone is sufficient to induce iPS formation in neural stem cells at later stages.