Daxx and histone deacetylase II associate with chromatin through an interaction with core histones and the chromatin-associated protein Dek.
Daxx and histone deacetylase II associate with chromatin through an interaction with core histones and the chromatin-associated protein Dek.
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发表时间：
2002-08
影响因子：
4
通讯作者：
A. Hollenbach;C. McPherson;E. Mientjes;R. Iyengar;G. Grosveld
中科院分区：
文献类型：
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作者：
A. Hollenbach;C. McPherson;E. Mientjes;R. Iyengar;G. Grosveld
人Daxx是一种蛋白质，其部分功能是通过与越来越多的核DNA相关蛋白相互作用而作为转录辅阻遏物。为了确定hDaxx抑制转录的机制，我们使用常规色谱法分离内源性hDaxx。我们确定hDaxx具有360 kDa的表观分子量，这与hDaxx的多个结构域是转录抑制所需的这一事实一致，并表明hDaxx与多种蛋白质相关联。使用共分馏和免疫共沉淀，我们证明，hDaxx协会与蛋白质的转录抑制是至关重要的，如组蛋白脱乙酰基酶II，染色质的组成部分，如核心组蛋白H2A，H2B，H3和H4，和Dek，染色质相关的蛋白质，报告改变拓扑结构的DNA染色质在体外。我们还证明了一个要求的SPT域和第一对两亲性螺旋的hDaxx与组蛋白去乙酰化酶II和乙酰化组蛋白H4，分别。最后，我们提供的证据表明，协会的hDaxx与染色质相关蛋白是依赖于翻译后磷酸化状态的hDaxx。一个工作模型的抑制作用hDaxx通过其与染色质相关的蛋白质。
Human Daxx is a protein that functions, in part, as a transcriptional co-repressor through its interaction with a growing number of nuclear, DNA-associated proteins. To determine the mechanism by which hDaxx represses transcription, we used conventional chromatography to isolate endogenous hDaxx. We determined that hDaxx has an apparent molecular weight of 360 kDa, which is consistent with the fact that multiple domains of hDaxx are required for transcriptional repression and suggests that hDaxx associates with multiple proteins. Using co-fractionation and co-immunoprecipitation we demonstrate that hDaxx associates with proteins that are critical for transcriptional repression, such as histone deacetylase II, constituents of chromatin such as core histones H2A, H2B, H3 and H4, and Dek, a chromatin-associated protein reported to change the topology of DNA in chromatin in vitro. We also demonstrate a requirement for the SPT domain and the first paired amphipathic helix of hDaxx for its association with histone deacetylase II and acetylated histone H4, respectively. Finally, we provide evidence suggesting that the association of hDaxx with chromatin-related proteins is dependent on the post-translational phosphorylation status of hDaxx. A working model for the repressive action of hDaxx through its association with chromatin related proteins is presented.