Thiry Marc, Lafontaine Denis L J
Laboratory of Cell and Tissue Biology, Department of Life Sciences, Faculty of Sciences, Université de Liège, Liège, Belgium.
Trends Cell Biol. 2005 Apr;15(4):194-9. doi: 10.1016/j.tcb.2005.02.007.
In eukaryotes, ribosome synthesis largely takes place in a specialized nuclear domain - the nucleolus. It has recently become apparent that this organelle is involved in the biogenesis of most cellular ribonucleoprotein particles (RNPs), as well as in cell-cycle regulation, making it central to gene expression. The field has traditionally acknowledged that each nucleolus is organized in three morphologically distinct compartments. Here, however, we discuss our view that in fact many eukaryotes have bipartite nucleoli. We propose that, during evolution, a third nucleolar compartment emerged at the transition between the anamniotes and the amniotes, following a substantial increase in size of the rDNA intergenic region. We believe that these conclusions have important implications for understanding the structure-function relationships within this key cellular organelle.
在真核生物中，核糖体合成主要发生在一个特殊的核区域——核仁。最近很明显的是，这个细胞器参与了大多数细胞核糖核蛋白颗粒（RNP）的生物发生，以及细胞周期调控，使其成为基因表达的核心。传统上，该领域认为每个核仁由三个形态上不同的区室组成。然而，在这里我们讨论我们的观点，即实际上许多真核生物具有二分核仁。我们提出，在进化过程中，随着rDNA基因间区域大小的大幅增加，在无羊膜动物和羊膜动物之间的过渡阶段出现了第三个核仁区室。我们认为这些结论对于理解这个关键细胞器内的结构-功能关系具有重要意义。
