【摘要】 采用机械破碎和蔗糖梯度离心方法从洋葱根端分生组织中分离出细胞核并制备出核 骨架。细胞核ＳＤＳ－ＰＡＧＥ谱带中１３５ｋＤ处有一多肽，免疫印迹实验结果表明，该多肽可被抗 鸡ＳｃⅡ抗体标记，核骨架中没有此多肽。经抗ＳｃⅡ抗体和ＦＩＴＣ偶联的二抗标记后，细胞核 发出代表ＳｃⅡ的特异性荧光，而核骨架中无荧光发出。经抗ＳｃⅡ抗体和蛋白Ａ胶体金处理 后，金颗粒特异性地结合在核内染色质区域。说明ＳｃⅡ类似蛋白是洋葱根端细胞核的组分， 且位于核内染色质上，但该蛋白不是核骨架成分。免疫荧光和免疫电镜实验结果还说明ＳｃⅡ 类似蛋白是洋葱根端细胞染色体和染色体骨架的组成成分。更多还原

【Abstract】 The nuclei were isolated from the root meristematic cells of Allium cepa and the nuclear matrices were prepared. A 135kD polypeptide, which is equivalent to ScⅡ in molecular weight was revealed in the nuclei by SDS-PAGE and was then demonstrated to be an Sc Ⅱ-like protein by Western blot with an anti-chicken Sc Ⅱ antiserum. Neither the 135kD polypeptide nor the positive labelling of the anti-Sc Ⅱ antiserum was found in the nuclear matrices. The immuno-fluorescence tests showed that the nuclei labelled with the anti-Sc Ⅱ antiserum emanated strong, specific fluorescence, while the fluorescence of the nuclear matrices was too weak to be detected. The results of immunoelectron microscopy indicated that a large number of the gold particles were concentrated in the condensed chromatin of the nuclei, but very few gold particles were distributed in cytoplasm and nucleoplasm. These results strongly suggested that an Sc Ⅱ like protein is a component of the nuclei of A. cepa and is mainly located in the condensed chromatin regions, but the nuclear matrices contain no or very little amount of that protein. By means of immunofluorescence and immunoelectron microscopy, the chromosomes and chromosomal scaffolds of A. cepa labelled with the anti-chicken Sc Ⅱ antiserum were observed to send off specific fluorescence and have many gold particles representing the presence of the Sc Ⅱ -like protein distributed among them. The significance of the Sc Ⅱ-like protein as a novel component in the nuclei, chromosomes and chromosome scaffolds of higher plants is discussed.更多还原