CpG-binding protein (CXXC finger protein 1) is a component of the mammalian set1 histone H3-Lys4 methyltransferase complex, the analogue of the yeast Set1/COMPASS complex
CpG-binding protein (CXXC finger protein 1) is a component of the mammalian set1 histone H3-Lys4 methyltransferase complex, the analogue of the yeast Set1/COMPASS complex
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DOI：
10.1074/jbc.m508312200
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发表时间：
2005-12-16
影响因子：
4.8
通讯作者：
Skalnik, DG
中科院分区：
文献类型：
--
作者：
Lee, JH;Skalnik, DG
CpG 结合蛋白（CXXC 指蛋白 1 (CFP1)）与含有未甲基化 CpG 基序的 DNA 结合，是哺乳动物胚胎发生、正常胞嘧啶甲基化和细胞分化所必需的。进行研究以确定与 CFP1 相互作用的蛋白质，以深入了解该蛋白质的分子功能。免疫沉淀和质谱分析表明，人 CFP1 与类似 450 kDa 的复合物结合，该复合物包含 Set1/COMPASS 复合物（酵母中唯一的组蛋白 H3-Lys(4) 甲基转移酶）七个成分中六个成分的哺乳动物同源物。体外测定表明，人 Set1/CFP1 复合物是一种组蛋白甲基转移酶，可在 Lys(4) 处产生单甲基化、二甲基化和三甲基化组蛋白 H3。共聚焦显微镜显示 CFP1 和 Set1 共定位于与常染色质相关的核斑点。质量减少的 Set1 复合物在缺乏 CFP1 的小鼠胚胎干细胞中持续存在。这些细胞的甲基化组蛋白 H3-Lys(4) 水平升高，而甲基化组蛋白 H3-Lys(9) 水平降低。与之前发现的胞嘧啶甲基化水平降低一起，这些数据表明缺乏 CFP1 的细胞异染色质水平降低。此外，缺乏CFP1的ES细胞在诱导分化后表现出4倍过量的组蛋白H3-Lys(4)甲基化，表明CFP1限制Set1组蛋白甲基转移酶复合物的活性。这些结果揭示了酵母 Set1/COMPASS 复合体的哺乳动物对应物。该复合物中 CFP1 的存在表明，除了胞嘧啶甲基化之外，该蛋白也是组蛋白修饰的关键表观遗传调节因子，并揭示了该蛋白与表观遗传机制相交叉的一种机制。
CpG-binding protein (CXXC finger protein 1 (CFP1)) binds to DNA containing unmethylated CpG motifs and is required for mammalian embryogenesis, normal cytosine methylation, and cellular differentiation. Studies were performed to identify proteins that interact with CFP1 to gain insight into the molecular function of this protein. Immunoprecipitation and mass spectrometry reveal that human CFP1 associates with a similar to 450-kDa complex that contains the mammalian homologues of six of the seven components of the Set1/COMPASS complex, the sole histone H3-Lys(4) methyltransferase in yeast. In vitro assays demonstrate that the human Set1/CFP1 complex is a histone methyltransferase that produces mono-, di-, and trimethylated histone H3 at Lys(4). Confocal microscopy reveals that CFP1 and Set1 co-localize to nuclear speckles associated with euchromatin. A Set1 complex of reduced mass persists in murine embryonic stem cells lacking CFP1. These cells carry elevated levels of methylated histone H3-Lys(4) and reduced levels of methylated histone H3-Lys(9). Together with the previous finding of reduced levels of cytosine methylation, these data indicate that cells lacking CFP1 contain reduced levels of heterochromatin. Furthermore, ES cells lacking CFP1 exhibit a 4-fold excess of histone H3-Lys(4) methylation following induction of differentiation, indicating that CFP1 restricts the activity of the Set1 histone methyltransferase complex. These results reveal amammalian counterpart to the yeast Set1/COMPASS complex. The presence of CFP1 in this complex implicates this protein as a critical epigenetic regulator of histone modification in addition to cytosine methylation and reveals one mechanism by which this protein intersects with the epigenetic machinery.