小柯机器人

德国马克斯·普朗克生物物理化学研究所Patrick Cramer课题组解析出RNA聚合酶II预起始复合物的结构。2021年6月15日，国际知名学术期刊《细胞》在线发表了这一成果。

研究人员表示，转录起始需要组装RNA聚合酶 II（Pol II）预起始复合物（PIC）并打开启动子DNA。

研究人员报道了酵母PIC的高分辨率结构，并定义了起始DNA开放的机制。研究人员将PIC捕获在中间状态，其中包含位于TATA框下游30-35个碱基对处的半圈开放DNA。起始打开的DNA区域的两侧是聚合酶“钳头环”和TFIIF“带电区域”，它们都有助于启动子启动的转录。TFIIE通过支撑夹头环和调节TFIIH转位酶来促进起始。起始的DNA泡随后向上游方向延伸，形成开放的启动子复合物并实现起始位点扫描和RNA合成。

这种独特的DNA开放机制可能实现比Pol I和Pol III系统更复杂的调节。

附：英文原文

Title: Structure of RNA polymerase II pre-initiation complex at 2.9 defines initial DNA opening

Author: Sandra Schilbach, Shintaro Aibara, Christian Dienemann, Frauke Grabbe, Patrick Cramer

Issue&Volume: 2021-06-15

Abstract: Transcription initiation requires assembly of the RNA polymerase II (Pol II) pre-initiationcomplex (PIC) and opening of promoter DNA. Here, we present the long-sought high-resolutionstructure of the yeast PIC and define the mechanism of initial DNA opening. We trapthe PIC in an intermediate state that contains half a turn of open DNA located 30–35base pairs downstream of the TATA box. The initially opened DNA region is flankedand stabilized by the polymerase “clamp head loop” and the TFIIF “charged region”that both contribute to promoter-initiated transcription. TFIIE facilitates initiationby buttressing the clamp head loop and by regulating the TFIIH translocase. The initialDNA bubble is then extended in the upstream direction, leading to the open promotercomplex and enabling start-site scanning and RNA synthesis. This unique mechanismof DNA opening may permit more intricate regulation than in the Pol I and Pol IIIsystems.

DOI: 10.1016/j.cell.2021.05.012

Source: https://www.cell.com/cell/fulltext/S0092-8674(21)00629-2