Inosine cyanoethylation identifies A-to-I RNA editing sites in the human transcriptome

Nat Chem Biol. 2010 Oct;6(10):733-40. doi: 10.1038/nchembio.434. Epub 2010 Sep 12.


Adenosine-to-inosine (A-to-I) RNA editing is a post-transcriptional processing event involved in diversifying the transcriptome responsible for various biological processes. Although bioinformatic approaches have predicted a number of A-to-I editing sites in cDNAs, the human transcriptome is thought to still harbor large numbers of as-yet-unknown editing sites. Exploring new editing sites requires a biochemical method to accurately identify inosines on RNA strands. We here describe a chemical method to identify inosines, called inosine chemical erasing (ICE), that is based on cyanoethylation combined with reverse transcription. We carried out a large-scale verification of the ICE method focusing on 642 regions in human cDNA and identified 5,072 editing sites, including 4,395 new sites. Functional study revealed that A-to-I intronic editing in the SARS gene mediated by ADAR1 is involved in preventing aberrant exonization of Alu sequence into mature mRNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / chemistry
  • Adenosine / metabolism*
  • Adenosine Deaminase / genetics
  • Alkylation
  • Alu Elements / genetics
  • Amino Acid Sequence
  • Base Sequence
  • DNA, Complementary
  • Exons / genetics
  • Gene Expression Profiling*
  • Humans
  • Inosine / analysis*
  • Inosine / chemistry*
  • Inosine / metabolism
  • Molecular Sequence Data
  • RNA Editing / genetics*
  • RNA-Binding Proteins
  • Serine-tRNA Ligase / genetics


  • DNA, Complementary
  • RNA-Binding Proteins
  • Inosine
  • ADARB1 protein, human
  • Adenosine Deaminase
  • Serine-tRNA Ligase
  • Adenosine