Investigating molecular mechanisms of 2A-stimulated ribosomal pausing and frameshifting in Theilovirus

Nucleic Acids Res. 2021 Nov 18;49(20):11938-11958. doi: 10.1093/nar/gkab969.


The 2A protein of Theiler's murine encephalomyelitis virus (TMEV) acts as a switch to stimulate programmed -1 ribosomal frameshifting (PRF) during infection. Here, we present the X-ray crystal structure of TMEV 2A and define how it recognises the stimulatory RNA element. We demonstrate a critical role for bases upstream of the originally predicted stem-loop, providing evidence for a pseudoknot-like conformation and suggesting that the recognition of this pseudoknot by beta-shell proteins is a conserved feature in cardioviruses. Through examination of PRF in TMEV-infected cells by ribosome profiling, we identify a series of ribosomal pauses around the site of PRF induced by the 2A-pseudoknot complex. Careful normalisation of ribosomal profiling data with a 2A knockout virus facilitated the identification, through disome analysis, of ribosome stacking at the TMEV frameshifting signal. These experiments provide unparalleled detail of the molecular mechanisms underpinning Theilovirus protein-stimulated frameshifting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Frameshifting, Ribosomal*
  • Ribosomes / metabolism
  • Theilovirus / genetics
  • Theilovirus / metabolism
  • Viral Proteins / chemistry
  • Viral Proteins / metabolism*


  • Viral Proteins
  • virus protein 2A