Structural insights into the nucleic acid remodeling mechanisms of the yeast THO-Sub2 complex

Elife. 2020 Nov 16:9:e61467. doi: 10.7554/eLife.61467.

Abstract

The yeast THO complex is recruited to active genes and interacts with the RNA-dependent ATPase Sub2 to facilitate the formation of mature export-competent messenger ribonucleoprotein particles and to prevent the co-transcriptional formation of RNA:DNA-hybrid-containing structures. How THO-containing complexes function at the mechanistic level is unclear. Here, we elucidated a 3.4 Å resolution structure of Saccharomyces cerevisiae THO-Sub2 by cryo-electron microscopy. THO subunits Tho2 and Hpr1 intertwine to form a platform that is bound by Mft1, Thp2, and Tex1. The resulting complex homodimerizes in an asymmetric fashion, with a Sub2 molecule attached to each protomer. The homodimerization interfaces serve as a fulcrum for a seesaw-like movement concomitant with conformational changes of the Sub2 ATPase. The overall structural architecture and topology suggest the molecular mechanisms of nucleic acid remodeling during mRNA biogenesis.

Keywords: CryoEM; R-loops; RNA; RNA export; S. cerevisiae; helicase; molecular biophysics; structural biology; transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry*
  • Adenosine Triphosphatases / metabolism
  • Cryoelectron Microscopy
  • Nucleic Acids / chemistry
  • Nucleic Acids / metabolism
  • Protein Conformation
  • Ribonucleoproteins / chemistry
  • Ribonucleoproteins / metabolism
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism

Substances

  • Nucleic Acids
  • Ribonucleoproteins
  • Saccharomyces cerevisiae Proteins
  • THO2 protein, S cerevisiae
  • Transcription Factors
  • messenger ribonucleoprotein
  • Adenosine Triphosphatases
  • RNA-dependent ATPase