Hock R, Carl M, Lieb B, Gebauer D, Scheer U
Department of Cell and Developmental Biology, Theodor-Boveri-Institute (Biocenter), University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Chromosoma. 1996;104(5):358-66. doi: 10.1007/BF00337225.
By immunizing Balb/c mice with oocyte nuclei of Pleurodeles waltl we obtained a monoclonal antibody, mAb 4A6, that labels distinct globular domains of the lampbrush chromosomal axes of Pleurodeles. These domains are found at corresponding sites of homologous chromosomes, often at telomeric and putative centromeric regions, and appear to be devoid of DNA. Because of these characteristic features it is most likely that the mAb 4A6-positive domains correspond to the central part of the "axial granules" of urodelan lampbrush chromosomes. In immunoblotting analyses mAb 4A6 reacts with a nuclear antigen of approximately Mr 180000 and a structurally nonrelated cytoplasmic protein of Mr 98000, which was not characterized any further. Comparative immunofluorescence and immunoblotting studies with mAb 4A6 and an antiserum against DNA topoisomerase II (topo II) as well as immunodepletion experiments demonstrated that the nuclear 4A6 antigen is topo II. Our results indicate that topo II is not a constituent of a continuous, loop-anchoring scaffold in lampbrush chromosomes of Pleurodeles but, rather, is restricted to the axial granules.
通过用沃氏肋突螈的卵母细胞核免疫Balb/c小鼠，我们获得了一种单克隆抗体mAb 4A6，它能标记沃氏肋突螈灯刷染色体轴的不同球状结构域。这些结构域位于同源染色体的相应位点，通常在端粒和假定的着丝粒区域，并且似乎不含DNA。由于这些特征，很可能mAb 4A6阳性结构域对应于有尾类灯刷染色体“轴向颗粒”的中心部分。在免疫印迹分析中，mAb 4A6与一种分子量约为180000的核抗原以及一种分子量为98000的结构无关的细胞质蛋白发生反应，对该细胞质蛋白未作进一步鉴定。用mAb 4A6和抗DNA拓扑异构酶II（topo II）抗血清进行的比较免疫荧光和免疫印迹研究以及免疫耗竭实验表明，核4A6抗原是topo II。我们的结果表明，topo II不是沃氏肋突螈灯刷染色体中连续的、环锚定支架的组成部分，而是局限于轴向颗粒。
