Escande-Géraud M L, Azum M C, Tichadou J L, Gas N
Exp Cell Res. 1985 Dec;161(2):353-63. doi: 10.1016/0014-4827(85)90092-8.
A major nucleolar protein with a molecular weight of 100 kD is directly implicated in the transcription of pre-ribosomal RNA (pre-rRNA) and appears to be cleaved into specific maturation products during pre-ribosome biogenesis. Polyclonal antibodies which recognize the 100 kD protein and its products were used to determine the correlation between rDNA transcription and these proteins. Actinomycin D (AMD) was used to block selectively rDNA transcription (AMD 0.1 microgram/ml). Immunoperoxidase and immunogold staining were carried out in untreated and treated cells. Digitalization allowed the quantification of label according to the nucleolar components and the cellular areas. In exponentially growing cells, the dense fibrillar component was shown to contain more 100 kD protein than the granular RNP component but both nucleolar components were positively immunostained. The distribution of the 100 kD protein was rapidly modified by AMD: loss of label occurred first in the dense fibrillar zone of the nucleolus, demonstrating the correlation between rDNA transcription and the presence of this protein. However, one part of the protein remains in the segregated nucleolus after 1 h of AMD treatment, thus supporting the structural function of this protein.
一种分子量为100 kD的主要核仁蛋白直接参与前核糖体RNA（pre-rRNA）的转录，并且在核糖体生物合成过程中似乎会被切割成特定的成熟产物。利用识别该100 kD蛋白及其产物的多克隆抗体来确定rDNA转录与这些蛋白之间的相关性。放线菌素D（AMD）用于选择性阻断rDNA转录（AMD 0.1微克/毫升）。在未处理和处理过的细胞中进行免疫过氧化物酶和免疫金染色。数字化处理使得能够根据核仁成分和细胞区域对标记进行定量分析。在指数生长的细胞中，致密纤维成分显示比颗粒状RNP成分含有更多的100 kD蛋白，但两种核仁成分均呈阳性免疫染色。AMD可迅速改变100 kD蛋白的分布：标记首先在核仁的致密纤维区消失，这表明rDNA转录与该蛋白的存在之间存在相关性。然而，AMD处理1小时后，该蛋白的一部分仍保留在分离的核仁中，从而支持了该蛋白的结构功能。
