Nucleoside modifications in RNA limit activation of 2'-5'-oligoadenylate synthetase and increase resistance to cleavage by RNase L

Nucleic Acids Res. 2011 Nov;39(21):9329-38. doi: 10.1093/nar/gkr586. Epub 2011 Aug 3.


The interferon-induced enzymes 2'-5'-oligoadenylate synthetase (OAS) and RNase L are key components of innate immunity involved in sensory and effector functions following viral infections. Upon binding target RNA, OAS is activated to produce 2'-5'-linked oligoadenylates (2-5A) that activate RNase L, which then cleaves single-stranded self and non-self RNA. Modified nucleosides that are present in cellular transcripts have been shown to suppress activation of several RNA sensors. Here, we demonstrate that in vitro transcribed, unmodified RNA activates OAS, induces RNase L-mediated ribosomal RNA (rRNA) cleavage and is rapidly cleaved by RNase L. In contrast, RNA containing modified nucleosides activates OAS less efficiently and induces limited rRNA cleavage. Nucleoside modifications also make RNA resistant to cleavage by RNase L. Examining translation in RNase L(-/-) cells and mice confirmed that RNase L activity reduces translation of unmodified mRNA, which is not observed with modified mRNA. Additionally, mRNA containing the nucleoside modification pseudouridine is translated longer and has an extended half-life. The observation that modified nucleosides in RNA reduce 2-5A pathway activation joins OAS and RNase L to the list of RNA sensors and effectors whose functions are limited when RNA is modified, confirming the role of nucleoside modifications in suppressing immune recognition of RNA.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 2',5'-Oligoadenylate Synthetase / metabolism*
  • Animals
  • Cells, Cultured
  • Endoribonucleases / metabolism*
  • Half-Life
  • Humans
  • Mice
  • Nucleosides / physiology*
  • Protein Biosynthesis
  • Pseudouridine / metabolism
  • RNA / chemistry*
  • RNA / metabolism
  • RNA, Ribosomal / metabolism
  • Uridine / physiology


  • Nucleosides
  • RNA, Ribosomal
  • Pseudouridine
  • RNA
  • 2',5'-Oligoadenylate Synthetase
  • Endoribonucleases
  • 2-5A-dependent ribonuclease
  • Uridine