Levy N, Navarro A, Moretti C, Barthelemy M, Stahl A
Laboratoire de Génétique et Cytogénétique, Faculté de Médecine de la Timone, Marseille, France.
Cell Mol Biol (Noisy-le-grand). 1996 Mar;42(2):159-68.
It is generally accepted that Ag-NORs proteins are associated with nucleolar components engaged in rRNA synthesis. Since conflicting results have been reported concerning the intranucleolar sites of active ribosomal genes, the relationships between the silver-stained areas and the distribution of rDNA were analyzed in human spermatogonia using confocal microscopy of fluorescent in situ hybridized preparations previously stained with silver. The fluorescent signal strictly corresponded to the silver-stained area, identified at the ultrastructural level as the fibrillar center and the surrounding dense fibrillar component. A quantitative evaluation of nucleolar activity solely based on silver-staining may be misleading, taking into account that only Ag-positive proteins located in the dense fibrillar component can be associated with transcriptional activity, while those stored in the fibrillar center are associated with non-transcribed rRNA genes.
人们普遍认为，银染核仁组织者区（Ag-NORs）蛋白与参与rRNA合成的核仁成分相关。由于关于活性核糖体基因在核仁内的位点已有相互矛盾的报道，因此利用共聚焦显微镜对先前经银染的荧光原位杂交制剂进行分析，研究了人类精原细胞中银染区域与rDNA分布之间的关系。荧光信号与银染区域严格对应，在超微结构水平上，银染区域被确定为纤维中心和周围的致密纤维成分。考虑到只有位于致密纤维成分中的Ag阳性蛋白可与转录活性相关，而储存在纤维中心的蛋白则与非转录的rRNA基因相关，仅基于银染对核仁活性进行定量评估可能会产生误导。
