Fischer D, Hock R, Scheer U
Department of Cell and Developmental Biology, Theodor-Boveri-Institute (Biocenter), University of Würzburg, Germany.
Exp Cell Res. 1993 Dec;209(2):255-60. doi: 10.1006/excr.1993.1309.
In somatic cells DNA topoisomerase II (topo II) is thought to be involved in the domain organization of the genome by anchoring the basis of chromatin loops to a chromosomal scaffold. Lampbrush chromosomes of amphibian oocytes directly display this radial loop organization in cytological preparations. In order to find out whether topo II may play a role in the organization of these meiotic chromosomes, we performed immunofluorescence studies using antibodies against Xenopus topo II. Our results indicate that topo II is apparently absent from lampbrush chromosomes and is hence unlikely to act as a "fastener" of the numerous lateral chromosomal loops. Topo II was, however, enriched in the amplified nucleoli of Xenopus oocytes.
在体细胞中，DNA拓扑异构酶II（拓扑II）被认为通过将染色质环的基部锚定到染色体支架上而参与基因组的结构域组织。两栖动物卵母细胞的灯刷染色体在细胞学制备物中直接显示出这种放射状环结构。为了弄清楚拓扑II是否可能在这些减数分裂染色体的组织中发挥作用，我们使用抗非洲爪蟾拓扑II的抗体进行了免疫荧光研究。我们的结果表明，灯刷染色体上显然不存在拓扑II，因此它不太可能作为众多侧向染色体环的“扣合器”。然而，拓扑II在非洲爪蟾卵母细胞的扩增核仁中富集。
