The nucleolus is the largest compartment of the eukaryotic cell's nucleus. It acts as a ribosome factory, thereby sustaining the translation machinery. The nucleolus is also the subnuclear compartment with the highest transcriptional activity in the cell, where hundreds of ribosomal RNA (rRNA) genes transcribe the overwhelming majority of RNAs. The structure and composition of the nucleolus change according to the developmental state. For instance, in embryonic stem cells (ESCs), rRNA genes display a hyperactive transcriptional state and open chromatin structure compared with differentiated cells. Increasing evidence indicates that the role of the nucleolus and rRNA genes might go beyond the control of ribosome biogenesis. One such role is linked to the genome architecture, since repressive domains are often located close to the nucleolus. This review highlights recent findings describing how the nucleolus is regulated in ESCs and its role in regulating ribosome biogenesis and genome organization for the maintenance of stem cell identity.

核仁是真核细胞核中最大的区室。它充当核糖体工厂，从而维持翻译机器。核仁也是细胞中转录活性最高的亚核区室，数百个核糖体 RNA (rRNA) 基因在此转录绝大多数 RNA。核仁的结构和组成根据发育状态而变化。例如，在胚胎干细胞 (ESC) 中，与分化细胞相比，rRNA 基因表现出高度活跃的转录状态和开放的染色质结构。越来越多的证据表明，核仁和 rRNA 基因的作用可能超出核糖体生物发生的控制。其中一种作用与基因组结构有关，因为抑制域通常位于核仁附近。这篇综述重点介绍了最近的研究结果，描述了 ESC 中核仁的调节方式及其在调节核糖体生物发生和基因组组织以维持干细胞身份方面的作用。