由RNA聚合酶III开放的分子机制
Matthias K Vorländer1, Heena Khatter1, Rene Wetzel1
1European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Nature
|January 19, 2018
概括
研究人员可视化了RNA聚合酶III (Pol III) 和转录因子IIIB (TFIIIB) 复合体. 这些结构揭示了TFIIIB如何结合DNA并招募Pol III来开始小RNA的转录.
科学领域:
- 分子生物学
- 结构生物学
- 生物化学
背景情况:
- RNA聚合酶III (Pol III) 转录了小的,结构化的RNA.
- 转录因子IIIB (TFIIIB) 对于Pol III转录的启动至关重要.
- 了解Pol III-TFIIIB复合体的组合和功能对于基因调节至关重要.
研究的目的:
- 确定不同功能状态下的Pol III-TFIIIB预启动复合物的结构.
- 阐明TFIIIB促进体DNA相互作用和Pol III的机制.
- 揭示TFIIIB和Pol III如何启动转录的DNA融化.
主要方法:
- 电子冷显微镜 (cryo-EM) 的分辨率在3.7 Å到5.5 Å之间.
- 对与自然促进体结合的Pol III预启动复合物的结构分析.
- 多种功能状态的表征,包括封闭的DNA,开放的DNA和最初的转录复合体.
主要成果:
- 在各种功能状态下获得了Pol III-TFIIIB复合物的高分辨率结构.
- 发现TFIIIB与促进体DNA之间存在非常紧密的多价值相互作用.
- 通过TFIIIB招募Pol III并启动DNA化的机制得到了阐明.
结论:
- TFIIIB与促进体DNA形成稳定的相互作用,促进了Pol III的招募.
- 由TFIIIB和C37子单元激活的Pol III特异性异构体启动了DNA化.
- 转录启动机制与Pol II系统有相似之处.
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