Waldeck W, Zentgraf H, Rösl F
Institute for Virus Research, German Cancer Research Center, Heidelberg.
Oncology. 1988;45(2):107-16. doi: 10.1159/000226543.
The association of topoisomerase II enzymes with papovavirus-chromatin has been described recently. We used cells infected with simian virus 40 (SV40) to investigate the in vivo effect of the topoisomerase II inhibitors nalidixic acid and novobiocin on the viral chromatin template. Blocking of topoisomerases inhibits DNA and RNA synthesis. The block with the inhibitors resulted in a conversion of a 95- to 75-svedberg chromatin to a 180- to 150-svedberg component accompanied with a variation in the topological linking number of the DNA. The condensed chromatin fractions (180-150 S) from inhibited cells resemble encapsidation intermediates and their DNA has a linking number as the DNA extracted from purified virions. Moreover, the virion DNA has a higher superhelical density compared to intracellular chromatin isolated from untreated cells and argues for a supercoiling activity in the cell.
拓扑异构酶II与乳头瘤病毒染色质的关联最近已有报道。我们利用感染了猴病毒40（SV40）的细胞来研究拓扑异构酶II抑制剂萘啶酸和新生霉素对病毒染色质模板的体内作用。拓扑异构酶的阻断会抑制DNA和RNA合成。用抑制剂阻断会导致95至75斯维德伯格单位的染色质转变为180至150斯维德伯格单位的组分，同时伴随着DNA拓扑连接数的变化。来自受抑制细胞的浓缩染色质组分（180 - 150 S）类似于衣壳化中间体，其DNA的连接数与从纯化病毒粒子中提取的DNA相同。此外，与从未经处理的细胞中分离出的细胞内染色质相比，病毒粒子DNA具有更高的超螺旋密度，这表明细胞中存在超螺旋活性。
