Department of Cell and Developmental Biology, Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Mamm Genome. 2022 Jun;33(2):402-411. doi: 10.1007/s00335-021-09906-z. Epub 2021 Aug 26.
The nucleolus is the largest sub-nuclear domain, serving primarily as the place for ribosome biogenesis. A delicately regulated function of the nucleolus is vital to the cell not only for maintaining proper protein synthesis but is also tightly associated with responses to different types of cellular stresses. Recently, several long non-coding RNAs (lncRNAs) were found to be part of the regulatory network that modulate nucleolar functions. Several of these lncRNAs are encoded in the ribosomal DNA (rDNA) repeats or are transcribed from the genomic regions that are located near the nucleolus organizer regions (NORs). In this review, we first discuss the current understanding of the sequence of the NORs and variations between different NORs. We then focus on the NOR-derived lncRNAs in mammalian cells and their functions in rRNA transcription and the organization of nucleolar structure under different cellular conditions. The identification of these lncRNAs reveals great potential of the NORs in harboring novel genes involved in the regulation of nucleolar functions.
核仁是最大的亚核结构域，主要作为核糖体生物发生的场所。核仁的精细调节功能对细胞至关重要，不仅对于维持适当的蛋白质合成是必需的，而且还与对不同类型的细胞应激的反应密切相关。最近，发现了几种长非编码 RNA（lncRNA）作为调节核仁功能的调控网络的一部分。这些 lncRNA 中的一些编码在核糖体 DNA（rDNA）重复序列中，或者从位于核仁组织者区域（NOR）附近的基因组区域转录。在这篇综述中，我们首先讨论了 NOR 序列和不同 NOR 之间的差异的当前理解。然后，我们专注于哺乳动物细胞中的 NOR 衍生的 lncRNA 及其在不同细胞条件下 rRNA 转录和核仁结构组织中的功能。这些 lncRNA 的鉴定揭示了 NOR 中蕴藏着参与核仁功能调节的新型基因的巨大潜力。
