Gouge Jerome, Guthertz Nicolas, Kramm Kevin, Dergai Oleksandr, Abascal-Palacios Guillermo, Satia Karishma, Cousin Pascal, Hernandez Nouria, Grohmann Dina, Vannini Alessandro
The Institute of Cancer Research, London, SW7 3RP, UK.
Department of Biochemistry, Genetics and Microbiology, Institute of Microbiology, University of Regensburg, 93053, Regensburg, Germany.
Nat Commun. 2017 Jul 25;8(1):130. doi: 10.1038/s41467-017-00126-1.
Initiation of gene transcription by RNA polymerase (Pol) III requires the activity of TFIIIB, a complex formed by Brf1 (or Brf2), TBP (TATA-binding protein), and Bdp1. TFIIIB is required for recruitment of Pol III and to promote the transition from a closed to an open Pol III pre-initiation complex, a process dependent on the activity of the Bdp1 subunit. Here, we present a crystal structure of a Brf2-TBP-Bdp1 complex bound to DNA at 2.7 Å resolution, integrated with single-molecule FRET analysis and in vitro biochemical assays. Our study provides a structural insight on how Bdp1 is assembled into TFIIIB complexes, reveals structural and functional similarities between Bdp1 and Pol II factors TFIIA and TFIIF, and unravels essential interactions with DNA and with the upstream factor SNAPc. Furthermore, our data support the idea of a concerted mechanism involving TFIIIB and RNA polymerase III subunits for the closed to open pre-initiation complex transition.Transcription initiation by RNA polymerase III requires TFIIIB, a complex formed by Brf1/Brf2, TBP and Bdp1. Here, the authors describe the crystal structure of a Brf2-TBP-Bdp1 complex bound to a DNA promoter and characterize the role of Bdp1 in TFIIIB assembly and pre-initiation complex formation.
RNA聚合酶（Pol）III启动基因转录需要TFIIIB的活性，TFIIIB是一种由Brf1（或Brf2）、TBP（TATA结合蛋白）和Bdp1组成的复合物。TFIIIB对于招募Pol III以及促进从封闭的Pol III预起始复合物向开放的预起始复合物转变是必需的，这一过程依赖于Bdp1亚基的活性。在此，我们展示了一个与DNA结合的Brf2-TBP-Bdp1复合物的晶体结构，分辨率为2.7 Å，并结合了单分子荧光共振能量转移分析和体外生化分析。我们的研究提供了关于Bdp1如何组装到TFIIIB复合物中的结构见解，揭示了Bdp1与Pol II因子TFIIA和TFIIF之间的结构和功能相似性，并揭示了与DNA以及上游因子SNAPc的重要相互作用。此外，我们的数据支持了一种协同机制的观点，即TFIIIB和RNA聚合酶III亚基参与了从封闭到开放的预起始复合物转变。RNA聚合酶III的转录起始需要TFIIIB，它是由Brf1/Brf2、TBP和Bdp1组成的复合物。在此，作者描述了与DNA启动子结合的Brf2-TBP-Bdp1复合物的晶体结构，并表征了Bdp1在TFIIIB组装和预起始复合物形成中的作用。
