Suja J A, Hernandez-Verdun D
Departamento de Biología, Universidad Autónoma de Madrid, Spain.
Cytogenet Cell Genet. 1996;75(2-3):155-8. doi: 10.1159/000134468.
The ultrastructural distribution of the proteins responsible for the silver staining of NORs was analyzed on serial thin sections of preembedded silver-stained rat kangaroo PtK1 metaphase chromosomes. Our results show that the Ag-NOR proteins present a crescent-shaped distribution at the secondary constriction of each chromatid. Moreover, in some cases the crescent-shaped structures of both chromatids are not symmetrically arranged but show different orientations. These observations, together with our own and previously reported light microscopy results obtained on silver-stained mammalian chromosomes, lead us to suggest a mechanism for the formation of apparent secondary constrictions at NORs.
对预先包埋银染的大鼠袋鼠PtK1中期染色体的连续薄切片进行分析，以研究负责核仁组织区（NORs）银染的蛋白质的超微结构分布。我们的结果表明，Ag-NOR蛋白在每个染色单体的次缢痕处呈月牙形分布。此外，在某些情况下，两条染色单体的月牙形结构并非对称排列，而是呈现不同的方向。这些观察结果，连同我们自己以及先前报道的关于银染哺乳动物染色体的光学显微镜结果，使我们提出了一种在NORs处形成明显次缢痕的机制。
