Javaherian K, Liu L F
Nucleic Acids Res. 1983 Jan 25;11(2):461-72. doi: 10.1093/nar/11.2.461.
A DNA topoisomerase activity is found to be associated with the nucleosomes released by the Staphylococcal nuclease digestion of HeLa nuclei. Such an association is found to be salt dependent. A number of criteria have established that this DNA topoisomerase activity is due to HeLa topo I (Liu, L. F. and Miller, K. G. (1980) Proc. Natl. Acad. Sci. USA 78, 3489-3491). A similar association has been demonstrated from the in vitro studies using purified mononucleosomes and eukaryotic DNA topoisomerase I. Nonhistone HMG proteins and histone H1 are found to stimulate topoisomerase activity in vitro and form tight complexes with eukaryotic DNA topoisomerase I. The intimate interactions of topoisomerase I with chromosomal proteins and nucleosomes may be an essential feature of the topoisomerase function in vivo.
人们发现一种DNA拓扑异构酶活性与经葡萄球菌核酸酶消化HeLa细胞核所释放的核小体有关。这种关联是盐依赖性的。多项标准已确定这种DNA拓扑异构酶活性是由HeLa拓扑异构酶I所致（刘，L.F.和米勒，K.G.（1980年）《美国国家科学院院刊》78，3489 - 3491）。使用纯化的单核小体和真核DNA拓扑异构酶I进行的体外研究也证明了类似的关联。发现非组蛋白HMG蛋白和组蛋白H1在体外可刺激拓扑异构酶活性，并与真核DNA拓扑异构酶I形成紧密复合物。拓扑异构酶I与染色体蛋白和核小体的密切相互作用可能是其在体内功能的一个基本特征。
