Sirri Valentina, Urcuqui-Inchima Silvio, Roussel Pascal, Hernandez-Verdun Danièle
Nuclei and Cell Cycle, CNRS, Université Paris VI, Université Paris VII, Institut Jacques Monod, 2 place Jussieu, 75251, Paris Cedex 05, France.
Histochem Cell Biol. 2008 Jan;129(1):13-31. doi: 10.1007/s00418-007-0359-6. Epub 2007 Nov 29.
Nucleoli are the prominent contrasted structures of the cell nucleus. In the nucleolus, ribosomal RNAs are synthesized, processed and assembled with ribosomal proteins. RNA polymerase I synthesizes the ribosomal RNAs and this activity is cell cycle regulated. The nucleolus reveals the functional organization of the nucleus in which the compartmentation of the different steps of ribosome biogenesis is observed whereas the nucleolar machineries are in permanent exchange with the nucleoplasm and other nuclear bodies. After mitosis, nucleolar assembly is a time and space regulated process controlled by the cell cycle. In addition, by generating a large volume in the nucleus with apparently no RNA polymerase II activity, the nucleolus creates a domain of retention/sequestration of molecules normally active outside the nucleolus. Viruses interact with the nucleolus and recruit nucleolar proteins to facilitate virus replication. The nucleolus is also a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm by nucleolus disruption. The nucleolus plays several crucial functions in the nucleus: in addition to its function as ribosome factory of the cells it is a multifunctional nuclear domain, and nucleolar activity is linked with several pathologies. Perspectives on the evolution of this research area are proposed.
核仁是细胞核中显著的对比结构。在核仁中，核糖体RNA被合成、加工并与核糖体蛋白组装。RNA聚合酶I合成核糖体RNA，且该活性受细胞周期调控。核仁揭示了细胞核的功能组织，其中可观察到核糖体生物发生不同步骤的区室化，而核仁机制则与核质和其他核体进行着持续的交换。有丝分裂后，核仁组装是一个受细胞周期控制的时间和空间调节过程。此外，通过在细胞核中形成一个明显没有RNA聚合酶II活性的大区域，核仁创建了一个通常在核仁外活跃的分子的保留/隔离域。病毒与核仁相互作用并招募核仁蛋白以促进病毒复制。由于核仁破坏导致核糖体蛋白在核质中重新分布，核仁也是应激的传感器。核仁在细胞核中发挥着多种关键功能：除了作为细胞的核糖体工厂外，它还是一个多功能的核域，并且核仁活性与多种病理状况相关。本文还提出了该研究领域的发展前景。
