Structural visualization of RNA polymerase III transcription machineries

Yan Han, Chunli Yan, Susan Fishbain, Ivaylo Ivanov, Yuan He*

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

RNA polymerase III (Pol III) transcription initiation requires the action of the transcription factor IIIB (TFIIIB) and is highly regulated. Here, we determine the structures of Pol III pre-initiation complexes (PICs) using single particle cryo-electron microscopy (cryo-EM). We observe stable Pol III–TFIIIB complexes using nucleic acid scaffolds mimicking various functional states, in which TFIIIB tightly encircles the upstream promoter DNA. There is an intricate interaction between TFIIIB and Pol III, which stabilizes the winged-helix domains of the C34 subunit of Pol III over the active site cleft. The architecture of Pol III PIC more resembles that of the Pol II PIC than the Pol I PIC. In addition, we also obtain a 3D reconstruction of Pol III in complex with TFIIIB using the elongation complex (EC) scaffold, shedding light on the mechanism of facilitated recycling of Pol III prior to transcription re-initiation.

Original languageEnglish (US)
Article number40
JournalCell Discovery
Volume4
Issue number1
DOIs
StatePublished - Dec 1 2018

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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