Schwarzacher H G, Wachtler F
Institut der Universität Wien, Austria.
Ann Genet. 1991;34(3-4):151-60.
The structure of nucleoli differs widely according to their functional state. Main structural components of human and mammalian nucleoli are: the fibrillar centres (FC), the dense fibrillar component (DF), and the granular component (GC). A critical review of the recent literature and of the author's results suggests that in active nucleoli the rRNA gene repeats of the nucleolus organizing regions (NORs) are localized in the DF. The DF contains also enzymes and factors necessary for transcription, RNA processing, and pre-ribosome synthesis. The FC serves possibly as a stock of proteins, among them RNA-polymerase I. The GC is made up mainly of preribosomes. Non active (non transcribed) NORs may be situated far away from nucleoli within the cell nucleus.
核仁的结构根据其功能状态有很大差异。人和哺乳动物核仁的主要结构成分是：纤维中心（FC）、致密纤维成分（DF）和颗粒成分（GC）。对近期文献和作者研究结果的批判性综述表明，在活跃的核仁中，核仁组织区（NORs）的rRNA基因重复序列定位于DF。DF还包含转录、RNA加工和核糖体前体合成所需的酶和因子。FC可能作为蛋白质储备库，其中包括RNA聚合酶I。GC主要由核糖体前体组成。非活跃（非转录）的NORs可能位于细胞核内远离核仁的位置。
