A Distinct Switch in Interactions of the Histone H4 Tail Domain upon Salt-dependent Folding of Nucleosome Arrays
A Distinct Switch in Interactions of the Histone H4 Tail Domain upon Salt-dependent Folding of Nucleosome Arrays
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DOI：
10.1074/jbc.m114.595140
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发表时间：
2014-09-26
影响因子：
4.8
通讯作者：
Hayes, Jeffrey J.
中科院分区：
文献类型：
--
作者：
Pepenella, Sharon;Murphy, Kevin J.;Hayes, Jeffrey J.
核心组蛋白尾部结构域介导核小体间的相互作用，其指导核小体阵列折叠和浓缩成更高级的染色质结构。组蛋白H4尾部结构域通过接触H2 A/H2 B酸性补丁和相邻核小体的DNA促进阵列间相互作用（1，2）。同样，H4尾部-H2 A接触稳定阵列折叠（3）。然而，H4尾部结构域是否通过与相邻核小体的DNA的核小体间相互作用来稳定阵列折叠仍不清楚。我们利用定义的双链体阵列，其包含在H4尾的N末端具有光诱导交联剂的单个专门的核小体，以表征这些相互作用。我们观察到，H4尾专门参与与未折叠阵列中的DNA的阵列内相互作用。这些相互作用在阵列折叠过程中减弱，但在凝聚的染色质中未观察到核小体间、阵列内H4尾-DNA接触。然而，我们记录了H4尾的N末端与H2 A之间的接触。已知破坏H4-H2 A表面相互作用的乙酰化模拟物的安装没有增加H4-DNA核小体间相互作用的观察。这些结果表明，H4尾的多种功能需要凝聚的染色质内的靶向不同的相互作用。
The core histone tail domains mediate inter-nucleosomal interactions that direct folding and condensation of nucleosome arrays into higher-order chromatin structures. The histone H4 tail domain facilitates inter-array interactions by contacting both the H2A/H2B acidic patch and DNA of neighboring nucleosomes (1, 2). Likewise, H4 tail-H2A contacts stabilize array folding (3). However, whether the H4 tail domains stabilize array folding via inter-nucleosomal interactions with the DNA of neighboring nucleosomes remains unclear. We utilized defined oligonucleosome arrays containing a single specialized nucleosome with a photo-inducible cross-linker in the N terminus of the H4 tail to characterize these interactions. We observed that the H4 tail participates exclusively in intra-array interactions with DNA in unfolded arrays. These interactions are diminished during array folding, yet no inter-nucleosome, intra-array H4 tail-DNA contacts are observed in condensed chromatin. However, we document contacts between the N terminus of the H4 tail and H2A. Installation of acetylation mimics known to disrupt H4-H2A surface interactions did not increase observance of H4-DNA inter-nucleosomal interactions. These results suggest the multiple functions of the H4 tail require targeted distinct interactions within condensed chromatin.