The nucleolus is the largest substructure in the nucleus and forms around the nucleolar organizer regions (NORs), which comprise hundreds of rRNA genes. Recent evidence highlights further functions of the nucleolus that go beyond ribosome biogenesis. Data indicate that the nucleolus acts as a compartment for the location and regulation of repressive genomic domains and, together with the nuclear lamina, represents the hub for the organization of the inactive heterochromatin. In this review, we discuss recent findings that have revealed how nucleolar structure and rRNA gene chromatin states are regulated during early mammalian development and their contribution to the higher-order spatial organization of the genome.

中文翻译：

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胚胎早期发育中的核仁和rRNA基因染色质。

核仁是细胞核中最大的亚结构，并在包含数百个rRNA基因的核仁组织区（NORs）周围形成。最近的证据强调了核糖体的功能超出了核糖体的生物发生。数据表明，核仁充当抑制性基因组域的定位和调节的区室，并且与核层一起代表无活性异染色质组织的集线器。在这篇综述中，我们讨论了最近的发现，这些发现揭示了在早期哺乳动物发育过程中如何调节核仁结构和rRNA基因染色质状态，以及它们对基因组的高阶空间组织的贡献。