DIRECT EVIDENCE FOR THE EFFECT OF TRANSCRIPTION ON LOCAL DNA SUPERCOILING INVIVO
DIRECT EVIDENCE FOR THE EFFECT OF TRANSCRIPTION ON LOCAL DNA SUPERCOILING INVIVO
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DOI：
10.1016/0022-2836(92)90721-u
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发表时间：
1992-01-05
影响因子：
5.6
通讯作者：
WELLS, RD
中科院分区：
文献类型：
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作者：
RAHMOUNI, AR;WELLS, RD
(CG) 束的不同长度（74 至 14 个碱基对）的 B 到 Z 结构转变已被用作超螺旋探针，以检查体内特定遗传位点转录诱导的局部拓扑变化。局部拓扑报告序列表明，在稳态转录下，启动子上游区域的负超螺旋增加，而终止子下游区域的负超螺旋性减少。这一结果为以下观点提供了直接的体内证据：RNA聚合酶延伸复合物沿着双螺旋DNA易位，在其前面产生正超螺旋，在其后面产生负超螺旋。此外，这种双超螺旋结构域模型在转录区域内进行了测试，其中检测到由每个单独的 RNA 聚合酶的通过产生的高度负超螺旋。因此，这些数据表明诱导的超螺旋仅限于多聚酶系统中每个RNA聚合酶复合物的附近。
TheB-to-Zstructural transition of varying lengths (74 to 14 base-pairs) of (CG) tracts has been used as a superhelicity probe to examine the local topological changes induced by transcription at defined genetic lociin vivo. The local-topology reporter sequences indicate that under steady-state transcription the region upstream from the promoter experiences an increase in negative supercoiling whereas the region downstream from the terminator displays a decrease in negative superhelicity. This result provides directin vivoevidence for the notion that the translocation of an RNA polymerase elongation complex along the double-helical DNA generates positive supercoils in front of it and negative supercoils behind it. Also, this twin-supercoiled domain model was tested inside a transcribed region where a high degree of negative supercoiling generated by the passage of each individual RNA polymerase was detected. Hence, these data indicate that the induced supercoils are confined to the vicinity of each RNA polymerase complex in a multipolymerase system.