Overextended RNA:DNA hybrid as a negative regulator of RNA polymerase II processivity
Overextended RNA:DNA hybrid as a negative regulator of RNA polymerase II processivity
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DOI：
10.1006/jmbi.2000.3755
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发表时间：
2000-06-02
影响因子：
5.6
通讯作者：
Kashlev, M
中科院分区：
文献类型：
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作者：
Kireeva, ML;Komissarova, N;Kashlev, M
RNA聚合酶II的延伸复合体(EC)的稳定性需要在转录本3‘端的8个核苷酸的RNA：DNA杂交，而包含这种最小杂交的EC的稳定性不需要非模板DNA链。在这里，我们应用一种新开发的方法，从合成的RNA和DNA寡核苷酸中独立于启动子组装RNA聚合酶II的功能EC，以研究RNA长于8个核苷酸的复合体稳定所需的最小核酸阵列组成。我们发现，当RNA在转录过程中延伸超过14-16个核苷酸时，非模板DNA成为维持稳定的EC所必需的。我们的数据表明，在没有非模板DNA的情况下形成的过度延伸的RNA：DNA杂交体对EC的稳定性起到负调节作用。EC的解离与聚合酶沿着过度伸展的杂交的倒退有关。杂交体的双重作用为控制EC中正确的核酸结构和RNA聚合酶II的处理能力提供了一种机制。
An eight nucleotide RNA:DNA hybrid at the 3' end of the transcript is required for the stability of the elongation complex (EC) of RNA polymerase II. A non-template DNA strand is not needed for the stability of the EC, which contains this minimal hybrid. Here, we apply a recently developed method for promoter-independent assembly of functional EC of RNA polymerase II from synthetic RNA and DNA oligonucleotides to study the minimal composition of the nucleic acid array required for stability of the complex with RNA longer than eight nucleotides. We found that upon RNA extension beyond 14-16 nt in the course of transcription, non-template DNA becomes essential for maintaining a stable EC. Our data suggest that the overextended RNA:DNA hybrid formed in the absence the non-template DNA acts as a negative regulator of EC stability. The dissociation of the EC correlates with the backsliding of the polymerase along the overextended hybrid. The dual role of the hybrid provides a mechanism for the control of a correct nucleic acid architecture in the EC and of RNA polymerase II processivity.