Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for histone H2A variants and histone modifications in WT Col-0 seedlings.

How histone intrinsic sequence variation or regulatory modifications regulate nucleosome interactions with transcription remain unclear. To clarify this question, we examined how histone variants and histone modifications assemble in the Arabidopsis thaliana genome, identifying a limited number of chromatin states that divide euchromatin and heterochromatin in biologically significant subdomains. We showed that histone variants were as significant as histone modifications to determine the composition of chromatin states. The loss of function of the chromatin remodeler DECREASED IN DNA METHYLATION (DDM1) prevented the exchange between the histone variants H2A.Z and H2A.W over transposons resulting in their enrichment in chromatin states found only on proteins coding genes in the wild type. Hence, the dynamics of histone H2A variants exchange impacted the definition and distribution of chromatin states. We propose that dynamics of histone variants control the organization of histone modifications into chromatin states to achieve landmarks that signify the ability for transcription. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for histone H2A variants and histone modifications in seedlings . Each set has its own Input and H3

组蛋白固有序列变异或调控性修饰如何调控核小体与转录过程的相互作用，目前仍尚不明确。为阐明这一科学问题，本研究针对组蛋白变体（histone variants）与组蛋白修饰在拟南芥（Arabidopsis thaliana）基因组中的组装模式展开分析，鉴定出有限数目的染色质状态，可在具有生物学意义的亚结构域中区分常染色质（euchromatin）与异染色质（heterochromatin）。研究证实，组蛋白变体与组蛋白修饰在决定染色质状态组成方面具有同等重要的作用。染色质重塑因子DNA甲基化减少（DECREASED IN DNA METHYLATION, DDM1）的功能缺失，会阻断转座子区域内组蛋白变体H2A.Z与H2A.W之间的替换，导致这两种变体仅在野生型蛋白编码基因对应的染色质状态中富集。因此，组蛋白H2A变体的替换动态过程，会影响染色质状态的界定与分布模式。本研究提出，组蛋白变体的动态变化可调控组蛋白修饰组装为染色质状态，从而形成标记转录活性的表观遗传界标。本研究针对幼苗中的组蛋白H2A变体与组蛋白修饰开展染色质免疫共沉淀测序（ChIP-seq）实验，每组数据均配有对应的Input对照与H3组蛋白对照样本。