Petryniak B, Lutter L C
Cell. 1987 Jan 30;48(2):289-95. doi: 10.1016/0092-8674(87)90432-6.
We have used sedimentation analysis as well as agarose gel electrophoresis to characterize the topological state of the DNA of the Simian Virus 40 (SV40) transcription complex. We found that the complex DNA contained constrained topological tension, presumably resulting from nucleosome-like structures, but no detectable unconstrained (i.e., relaxable) topological tension. These results contradict previous conclusions that the SV40 transcription complex contains only unconstrained topological tension. Our findings are also the opposite of what has been proposed to be the case for the 5S gene analyzed in Xenopus oocytes. Thus the proposal that expression from the 5S gene is associated with substantial topological tension is not valid for expression from the SV40 late gene.
我们利用沉降分析以及琼脂糖凝胶电泳来表征猿猴病毒40（SV40）转录复合物中DNA的拓扑状态。我们发现该复合物DNA含有受限的拓扑张力，推测是由核小体样结构导致的，但未检测到可松弛的（即可解旋的）拓扑张力。这些结果与之前关于SV40转录复合物仅含有可松弛拓扑张力的结论相矛盾。我们的发现也与在非洲爪蟾卵母细胞中分析的5S基因的情况相反。因此，关于5S基因表达与大量拓扑张力相关的提议对于SV40晚期基因的表达并不成立。
