Identification and characterization of nucleoplasmin 3 as a histone-binding protein in embryonic stem cells
Identification and characterization of nucleoplasmin 3 as a histone-binding protein in embryonic stem cells
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DOI：
10.1111/j.1440-169x.2008.01034.x
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发表时间：
2008-06-01
影响因子：
2.5
通讯作者：
Yoshizato, Katsutoshi
中科院分区：
文献类型：
--
作者：
Motoi, Natsuki;Suzuki, Ken-ichi;Yoshizato, Katsutoshi
胚胎干（ES）细胞被认为具有独特的染色质结构，具有自我更新和多能性的能力。为了检验这种可能性，我们使用组蛋白 H3 和 H4 尾部结构域的合成肽作为诱饵，使用 Pull-down 测定在小鼠 ES 细胞中寻找与组蛋白特异性结合的核蛋白。核蛋白优先与后者结合。我们鉴定了 45 种与组蛋白 H4 尾相关的蛋白，并将它们分为四类：10 种染色质重塑蛋白、5 种组蛋白伴侣、2 种组蛋白修饰相关蛋白和 28 种其他蛋白。比较了从这 45 种蛋白质中选出的 20 种蛋白质在未分化和视黄酸 (RA) 诱导的分化 ES 细胞之间的 mRNA 表达水平。所有基因在两种状态的 ES 细胞中表达相似，但核纤蛋白 3 (NPM3) 除外，其在未分化细胞中表达水平较高。 NPM3 蛋白定位于细胞的核仁和细胞核中，并且在 RA 诱导的分化过程中表达降低。当转染NPM3基因时，与对照细胞相比，ES细胞的增殖显着增加。本研究强烈表明，NPM3 是一种染色质重塑蛋白，负责 ES 细胞独特的染色质结构和复制能力。
Embryonic stem (ES) cells are thought to have unique chromatin structures responsible for their capacity for self-renewal and pluripotency. To examine this possibility, we sought nuclear proteins in mouse ES cells that specifically bind to histones using a pull-down assay with synthetic peptides of histone H3 and H4 tail domain as baits. Nuclear proteins preferentially bound to the latter. We identified 45 proteins associated with the histone H4 tail and grouped them into four categories: 10 chromatin remodeling proteins, five histone chaperones, two histone modification-related proteins, and 28 other proteins. mRNA expression levels of 20 proteins selected from these 45 proteins were compared between undifferentiated and retinoic acid (RA)-induced differentiated ES cells. All of the genes were similarly expressed in both states of ES cells, except nucleoplasmin 3 (NPM3) that was expressed at a higher level in the undifferentiated cells. NPM3 proteins were localized in the nucleoli and nuclei of the cells and expression was decreased during RA-induced differentiation. When transfected with NPM3 gene, ES cells significantly increased their proliferation compared with control cells. The present study strongly suggests that NPM3 is a chromatin remodeling protein responsible for the unique chromatin structure and replicative capacity of ES cells.