Crystal structure of an adenovirus virus-associated RNA

Nat Commun. 2019 Jun 28;10(1):2871. doi: 10.1038/s41467-019-10752-6.

Abstract

Adenovirus Virus-Associated (VA) RNAs are the first discovered viral noncoding RNAs. By mimicking double-stranded RNAs (dsRNAs), the exceptionally abundant, multifunctional VA RNAs sabotage host machineries that sense, transport, process, or edit dsRNAs. How VA-I suppresses PKR activation despite its strong dsRNA character, and inhibits the crucial antiviral kinase to promote viral translation, remains largely unknown. Here, we report a 2.7 Å crystal structure of VA-I RNA. The acutely bent VA-I features an unusually structured apical loop, a wobble-enriched, coaxially stacked apical and tetra-stems necessary and sufficient for PKR inhibition, and a central domain pseudoknot that resembles codon-anticodon interactions and prevents PKR activation by VA-I. These global and local structural features collectively define VA-I as an archetypal PKR inhibitor made of RNA. The study provides molecular insights into how viruses circumnavigate cellular rules of self vs non-self RNAs to not only escape, but further compromise host innate immunity.

Publication types

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

MeSH terms

  • Adenoviruses, Human / genetics
  • Base Sequence
  • Crystallization
  • Light
  • Nucleic Acid Conformation*
  • RNA, Double-Stranded / chemistry*
  • RNA, Double-Stranded / genetics
  • RNA, Viral / chemistry*
  • RNA, Viral / genetics
  • eIF-2 Kinase / genetics
  • eIF-2 Kinase / metabolism

Substances

  • RNA, Double-Stranded
  • RNA, Viral
  • EIF2AK2 protein, human
  • eIF-2 Kinase