Chromatins are not randomly packaged in the nucleus and their organization plays important roles in transcription regulation, which is best studied in the mammalian models. Using in situ Hi‐C, we have compared the 3D chromatin architectures of rice mesophyll and endosperm, foxtail millet bundle sheath and mesophyll, and maize bundle sheath, mesophyll and endosperm tissues. We found that their global A/B compartment partitions are stable across tissues, while local A/B compartment has tissue‐specific dynamic associated with differential gene expression. Plant domains are largely stable across tissues, while new domain border formations are often associated with transcriptional activation in the region. Genes inside plant domains are not conserved across species, and lack significant co‐expression behavior unlike those in mammalian TADs. Although we only observed chromatin loops between gene islands in the large genomes, the maize loop gene pairs’ syntenic orthologs have shorter physical distances in small genome monocots, suggesting that loops instead of domains might have conserved biological function. Our study showed that plants’ chromatin features might not have conserved biological functions as the mammalian ones.

中文翻译：

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水稻，谷子和玉米的组织特异性Hi-C分析表明植物染色质域的非典型功能。

染色质不是随机包装在细胞核中，它们的组织在转录调控中起着重要作用，最好在哺乳动物模型中进行研究。原位使用在Hi-C中，我们比较了水稻叶肉和胚乳，谷子小米束鞘和叶肉以及玉米束鞘，叶肉和胚乳组织的3D染色质结构。我们发现，它们的整体A / B间隔在整个组织中是稳定的，而局部A / B间隔具有与差异基因表达相关的组织特异性动态。植物结构域在整个组织中基本上是稳定的，而新的结构域边界的形成通常与该区域的转录激活有关。植物结构域内部的基因在物种间并非保守，并且与哺乳动物TAD中的基因缺乏明显的共表达行为。尽管我们只观察到大型基因组中基因岛之间的染色质环，但玉米环基因对的同向直系同源物在小型基因组单子叶植物中具有较短的物理距离，提示环而不是域可能具有保守的生物学功能。我们的研究表明，植物的染色质特征可能不像哺乳动物一样具有保守的生物学功能。