组蛋白伴侣HIRA特异识别组蛋白变体H3.3-H4的结构研究

We focus this study on the structural mechanism of the recognition of variant histone H3.3-H4 by histone chaperon HIRA. Using X-ray crystallography, we aim to solve the complex structure of the HIRA-H3.3-H4 complex, and to elucidate the structural basis for the preferential binding of HIRA to H3.3 over canonical H3.1. Meanwhile, previous studies have shown that H3.3-H4 heterodimer is transferred to HIRA by another histone chaperon ASF1, and the association of other protein factors, like UBN1 and Cabin, may reinforce the interaction between HIRA and H3.3-H4. We will reconstitute the multiprotein complex and sub-complexes of the HIRA-ASF1-UBN1-Cabin-H3.3-H4 assembly and try to solve the crystal structures of these complexes, thus to provide structural basis for the specific recogniton of H3.3, as well as mechanistic insights into crosstalks between histone chaperones and other protein factors. These results will help our understanding of the function of H3.3 in the regulation of gene transcription via modulating the higer-order chromatin structure.

本项目围绕组蛋白伴侣HIRA特异识别组蛋白变体H3.3-H4的分子机理开展系列研究。拟通过结构生物学手段解析HIRA-H3.3-H4复合体的晶体结构，揭示HIRA对H3.3-H4偏好性的结构基础。已知HIRA在组蛋白H3.3-H4的转运和递放过程中会与伴侣ASF1、蛋白质因子UBN1和Cabin等发生相互作用，我们也将开展(HIRA-ASF1-UBN1-Cabin-H3.3-H4)多元复合物、亚复合物的组装及结构解析工作，为理解H3.3在不同组蛋白伴侣间的传递、蛋白因子对伴侣与变体间识别的影响等提供重要的结构基础，并为进一步围绕组蛋白变体对染色质高级结构的影响以及调控基因表达的研究提供线索。

本项目围绕组蛋白伴侣HIRA复合体特异识别组蛋白变体H3.3-H4的分子机理开展系列研究。完成了HIRA-H3.3-H4三元复合体、HIRA-UBN1-H3.3-H4四元复合体以及HIRA-ASF1-UBN1-H3.3-H4五元复合体，各组分的共表达纯化以及复合体的体外组装工作，并开展了大量的结晶筛选和晶体优化工作。得到了五元复合体可衍射的晶体，正在开展晶体优化和五元复合物结构解析工作，并为进一步围绕组蛋白变体对染色质高级结构的影响以及调控基因表达的研究提供线索。项目培养了博士毕业生2人，出站博士后1人晋升为副研究员。