The multicopy ribosomal DNA (rDNA) array gives origin to the nucleolus, a large nonmembrane-bound organelle that occupies a substantial volume within the cell nucleus. The rDNA/nucleolus has emerged as a coordinating hub in which seemingly disparate cellular functions converge, and from which a variety of cellular and organismal phenotypes emerge. However, the role of the nucleolus as a determinant and organizer of nuclear architecture and other epigenetic states of the genome is not well understood. We discuss the role of rDNA and the nucleolus in nuclear organization and function - from nucleolus-associated domains (NADs) to the regulation of imprinted loci and X chromosome inactivation, as well as rDNA contact maps that anchor and position the rDNA relative to the rest of the genome. The influence of the nucleolus on nuclear organization undoubtedly modulates diverse biological processes from metabolism to cell proliferation, genome-wide gene expression, maintenance of epigenetic states, and aging.

中文翻译：

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核糖体 DNA 和核仁作为核结构、组织和功能的基石。

多拷贝核糖体 DNA (rDNA) 阵列是核仁的起源，核仁是一种非膜结合的大细胞器，在细胞核内占据大量空间。rDNA/核仁已成为一个协调中心，看似不同的细胞功能汇聚于此，并从中出现各种细胞和生物体表型。然而，核仁作为核结构和基因组其他表观遗传状态的决定因素和组织者的作用尚不清楚。我们讨论了 rDNA 和核仁在核组织和功能中的作用——从核仁相关域 (NAD) 到印迹基因座和 X 染色体失活的调节，以及相对于其余部分锚定和定位 rDNA 的 rDNA 接触图基因组的。