组蛋白分子伴侣调控H2A.Z在全基因组分布的分子机制

H2A.Z is one of evolutionally conserved histone H2A variant, which is involved in transcription regulation, DNA damage response and other important biological events.Histone chaperone Nap1 and Chz1 have been found to be involved in the shuttle of H2A.Z between cytoplasm and nucleus. However, it remains largely unknown how Nap1 and Chz1 regulate the assembly and disassembly of H2A.Z into nucleosomes. In our preliminary experiment, our ChIP seq and biochemical studies have provided the genomic map of H2A.Z, Nap1 and Chz1. Interestingly, histone chaperone Nap1 showed a significant overlap with H2A.Z. In NAP1 mutant, H2A.Z binding on genome is dramatically increased. The above data indicated that histone chaperone Nap1 and Chz1 may play distinct roles to regulate the incorporation of H2A.Z into nucleosome. In this proposal, we will continue to study how H2A.Z binding pattern is affected in the absence of chaperone Nap1 and Chz1. By transcriptome analysis, we want to understand how H2A.Z can coordinate with histone chaperones to regulate transcription. What are the functional roles of H2A.Z and histone chaperones on chromatin structure by nucleosome sequencing? By means of proteomics, we will identify novel H2A.Z binding proteins in CHZ1 and NAP1 mutants. We believe that this study will generate great insights into the molecular mechanisms of H2A.Z incorporation and the relationship between chromatin structure and functional regulations.

H2A.Z是进化上高度保守的组蛋白H2A的变体之一，参与基因转录调控、DNA损伤修复等重要生物学事件。组蛋白分子伴侣Chz1和Nap1在H2A.Z的核质运输及染色质整合过程中起着重要的作用。但是它们调控H2A.Z在染色质的组装、去组装的作用机制尚不清楚。我们前期通过ChIP seq解析H2A.Z、Chz1和Nap1在全基因组的分布。结果发现Nap1与H2A.Z在基因组的分布具有高度重叠性，Nap1敲除后H2A.Z在染色质分布增多。本项目将继续深入研究在分子伴侣突变后H2A.Z在全基因组中的分布；通过表达谱芯片方法揭示分子伴侣及H2A.Z如何相互作用调控基因的转录；借助核小体测序探讨组蛋白分子伴侣及H2A.Z对染色质结构的影响；利用质谱鉴定分子伴侣Chz1和Nap1敲除后H2A.Z新的结合蛋白。通过对组蛋白分子伴侣功能的深入研究，有助于更全面地理解H2A.Z的整合机制和染色质结构与功能调控。

H2A.Z是进化上高度保守的组蛋白H2A的变体之一，参与基因转录调控、DNA损伤修复等重要生物学事件。组蛋白分子伴侣Chz1和Nap1在H2A.Z的核质运输及染色质整合过程中起着重要的作用。但是它们调控H2A.Z在染色质的组装、去组装的作用机制尚不清楚。本项目以酵母为模式生物，深入研究了组蛋白分子伴侣Chz1和Nap1在H2A.Z的核质运输及染色质整合过程中的作用机制。利用ChIP seq和生物信息学分析，解析了H2A.Z、Chz1和Nap1在全基因组的分布定位，揭示了Chz1和Nap1分子伴侣及H2A.Z如何相互作用调控基因的转录以及对染色质结构的影响。在缺失NAP1的突变体中，H2A.Z与染色体结合显著增加。上述结果充分说明了组蛋白分子伴侣Chz1和Nap1分别调节H2A.Z与染色体的组装，我们相信研究结果对H2A.Z分子机制的研究具有深远意义，并对通过不同的方式对缺失Htz1的染色质进行调控，并揭示了H2A.Z与染色体结构和功能的关系。