A LONG PURINE-PYRIMIDINE HOMOPOLYMER ACTS AS A TRANSCRIPTIONAL DIODE
A LONG PURINE-PYRIMIDINE HOMOPOLYMER ACTS AS A TRANSCRIPTIONAL DIODE
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DOI：
10.1074/jbc.270.4.1791
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发表时间：
1995-01-27
影响因子：
4.8
通讯作者：
FISHMAN, MC
中科院分区：
文献类型：
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作者：
GRABCZYK, E;FISHMAN, MC
多嘌呤-多嘧啶(R.Y)序列具有形成DNA三螺旋的特殊能力。这类区域在真核基因的上游被过度表达，尽管那里的功能尚不清楚。我们报告了在体外转录到这样一个这样的上游R.Y区的方向，使主要是嘌呤RNA有效地阻止了分子内三螺旋的形成。三倍体由转录触发，并通过新生嘌呤RNA与模板的结合而稳定。相反方向的转录不受限制。多嘌呤-多嘧啶DNA可以在没有辅助蛋白的情况下提供动态的和选择性的转录阻断。
Polypurine-polypyrimidine (R.Y) sequences have the unusual ability to form DNA triple helices. Such tracts are overrepresented upstream of eukaryotic genes, although a function there has not been clear. We report that transcription in vitro into one such upstream R.Y tract in the direction that makes a predominantly purine RNA is effectively blocked by formation of an intramolecular triple helix. The tripler is triggered by transcription and stabilized by the binding of nascent purine RNA to the template. Transcription in the opposite direction is not restricted. Polypurine-polypyrimidine DNA may provide a dynamic and selective block to transcription without the aid of accessory proteins.