Hozák P, Cook P R, Schöfer C, Mosgöller W, Wachtler F
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague.
J Cell Sci. 1994 Feb;107 ( Pt 2):639-48. doi: 10.1242/jcs.107.2.639.
Sites of transcription of ribosomal RNA in HeLa cells were visualized by electron microscopy. Cells were either incubated with Br-uridine, or permeabilized and then incubated with BrUTP, before sites containing Br-RNA were immunolabeled with gold particles. Short incubations ensured that most incorporated analogue remained at synthetic sites. Fibrillar centres were unlabelled except at their periphery; label was concentrated over certain regions of the surrounding dense fibrillar component. These results suggest that the dense fibrillar component is the site of rRNA transcription. After dispersing the granular component and the dense fibrillar component by a hypotonic treatment, removal of most chromatin and preparation of resinless sections, fibrillar centres remained fixed to a nucleoskeleton. These structural and functional features are incorporated into a model for rRNA transcription.
通过电子显微镜观察了HeLa细胞中核糖体RNA的转录位点。细胞先用溴尿苷孵育，或者先进行通透处理，然后用溴尿苷三磷酸（BrUTP）孵育，之后用金颗粒对含有溴化RNA的位点进行免疫标记。短时间孵育确保大多数掺入的类似物仍留在合成位点。纤维中心除了其周边未被标记外，标记集中在周围致密纤维成分的某些区域。这些结果表明致密纤维成分是rRNA转录的位点。通过低渗处理分散颗粒成分和致密纤维成分、去除大部分染色质并制备无树脂切片后，纤维中心仍固定在核骨架上。这些结构和功能特征被纳入rRNA转录的模型中。
