Cryo-EM and antisense targeting of the 28-kDa frameshift stimulation element from the SARS-CoV-2 RNA genome

Nat Struct Mol Biol. 2021 Sep;28(9):747-754. doi: 10.1038/s41594-021-00653-y. Epub 2021 Aug 23.

Abstract

Drug discovery campaigns against COVID-19 are beginning to target the SARS-CoV-2 RNA genome. The highly conserved frameshift stimulation element (FSE), required for balanced expression of viral proteins, is a particularly attractive SARS-CoV-2 RNA target. Here we present a 6.9 Å resolution cryo-EM structure of the FSE (88 nucleotides, ~28 kDa), validated through an RNA nanostructure tagging method. The tertiary structure presents a topologically complex fold in which the 5' end is threaded through a ring formed inside a three-stem pseudoknot. Guided by this structure, we develop antisense oligonucleotides that impair FSE function in frameshifting assays and knock down SARS-CoV-2 virus replication in A549-ACE2 cells at 100 nM concentration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • A549 Cells
  • Animals
  • Base Sequence
  • COVID-19 / prevention & control*
  • COVID-19 / virology
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Cryoelectron Microscopy / methods*
  • Frameshift Mutation / genetics*
  • Genome, Viral / genetics
  • Humans
  • Models, Molecular
  • Nucleic Acid Conformation
  • Oligonucleotides, Antisense / genetics*
  • Oligonucleotides, Antisense / pharmacology
  • RNA, Viral / chemistry
  • RNA, Viral / genetics*
  • RNA, Viral / ultrastructure
  • Response Elements / genetics*
  • SARS-CoV-2 / genetics*
  • SARS-CoV-2 / physiology
  • SARS-CoV-2 / ultrastructure
  • Vero Cells
  • Virus Replication / drug effects
  • Virus Replication / genetics

Substances

  • Oligonucleotides, Antisense
  • RNA, Viral