Site-directed RNA repair of endogenous Mecp2 RNA in neurons

John R. Sinnamon, Susan Y. Kim, Glen M. Corson, Zhen Song, Hiroyuki Nakai, John P. Adelman, Gail Mandel

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Rett syndrome (RTT) is a debilitating neurological disorder caused by mutations in the gene encoding the transcription factor Methyl CpG Binding Protein 2 (MECP2). A distinct disorder results from MECP2 gene duplication, suggesting that therapeutic approaches must restore close to normal levels of MECP2. Here, we apply the approach of site-directed RNA editing to repair, at the mRNA level, a disease-causing guanosine to adenosine (G > A) mutation in the mouse MeCP2 DNA binding domain. To mediate repair, we exploit the catalytic domain of Adenosine Deaminase Acting on RNA (ADAR2) that deaminates A to inosine (I) residues that are subsequently translated as G. We fuse the ADAR2 domain, tagged with a nuclear localization signal, to an RNA binding peptide from bacteriophage lambda. In cultured neurons from mice that harbor an RTT patient G > A mutation and express engineered ADAR2, along with an appropriate RNA guide to target the enzyme, 72% of Mecp2 mRNA is repaired. Levels of MeCP2 protein are also increased significantly. Importantly, as in wild-type neurons, the repaired MeCP2 protein is enriched in heterochromatic foci, reflecting restoration of normal MeCP2 binding to methylated DNA. This successful use of site-directed RNA editing to repair an endogenous mRNA and restore protein function opens the door to future in vivo applications to treat RTT and other diseases.

Original languageEnglish (US)
Pages (from-to)E9395-E9402
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Oct 31 2017


  • ADAR2
  • MeCP2
  • RNA editing
  • Rett syndrome

ASJC Scopus subject areas

  • General


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