Goodpasture C, Bloom S E
Chromosoma. 1975 Nov 20;53(1):37-50. doi: 10.1007/BF00329389.
A simple ammoniacal silver staining procedure, designated Ag-AS, differentially stains the chromosomal locations of ribosomal DNA in certain mammalian species. This was critically demonstrated by Ag-AS staining of the nucleolus organizer regions in karyotypes of the same species and cell lines used for locating the ribosomal cistrons by DNA/RNA in situ hybridization. With Ag-AS, silver stained NORs (Ag-NORs) are visualized as black spherical bodies on yellow-brown chromosome arms. Ag-NORs were visualized throughout mitosis at the secondary constrictions in the rat kangaroo, Seba's fruit bat, Indian muntjac, and Rhesus monkey. The Chinese hamster and cattle have telomeric Ag-NORs, the mouse subcentromeric Ag-NORs, and the field vole Ag-NORs as minute short arms or choromosomal satellites. Ag-NORs occur at both secondary constrictions and at telomeres in the cotton rat. Variability in Ag-NOR pattern included differences in the number of Ag-NORs per cell within a cell population, size of Ag-NORs among chromosomes of a complement, and presence of Ag-NOR on particular chromosomes in two cell lines of the Chinese hamster. The available cytochemical data suggest that the Ag-AS reaction stains chromosomal proteins at the NOR rather than the rDNA itself.
一种简单的氨银染色程序，称为Ag-AS，可对某些哺乳动物物种核糖体DNA的染色体位置进行差异染色。通过对用于DNA/RNA原位杂交定位核糖体顺反子的同一物种和细胞系的核型中的核仁组织区进行Ag-AS染色，这一点得到了关键证明。使用Ag-AS时，银染的核仁组织区（Ag-NORs）在黄棕色染色体臂上呈现为黑色球体。在大鼠袋鼠、塞巴氏果蝠、印度麂和恒河猴的整个有丝分裂过程中，均可在次缢痕处观察到Ag-NORs。中国仓鼠和牛有端粒Ag-NORs，小鼠有亚着丝粒Ag-NORs，田鼠的Ag-NORs为微小的短臂或染色体随体。棉鼠的Ag-NORs出现在次缢痕和端粒处。Ag-NOR模式的变异性包括细胞群体中每个细胞的Ag-NOR数量差异、一组染色体中Ag-NOR的大小差异，以及中国仓鼠两个细胞系中特定染色体上Ag-NOR的存在情况。现有的细胞化学数据表明Ag-AS反应染色的是核仁组织区的染色体蛋白而非rDNA本身。
