Antisense proline-arginine RAN dipeptides linked to C9ORF72-ALS/FTD form toxic nuclear aggregates that initiate in vitro and in vivo neuronal death

Neuron. 2014 Dec 17;84(6):1213-25. doi: 10.1016/j.neuron.2014.12.010.


Expanded GGGGCC (G4C2) nucleotide repeats within the C9ORF72 gene are the most common genetic mutation associated with both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Sense and antisense transcripts of these expansions are translated to form five dipeptide repeat proteins (DRPs). We employed primary cortical and motor neuron cultures, live-cell imaging, and transgenic fly models and found that the arginine-rich dipeptides, in particular Proline-Arginine (PR), are potently neurotoxic. Factors that anticipated their neurotoxicity included aggregation in nucleoli, decreased number of processing bodies, and stress granule formation, implying global translational dysregulation as path accountable for toxicity. Nuclear PR aggregates were also found in human induced motor neurons and postmortem spinal cord tissues from C9ORF72 ALS and ALS/FTD patients. Intronic G4C2 transcripts, but not loss of C9ORF72 protein, are also toxic to motor and cortical neurons. Interestingly, G4C2 transcript-mediated neurotoxicity synergizes with that of PR aggregates, suggesting convergence of mechanisms.

Publication types

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

MeSH terms

  • Amyotrophic Lateral Sclerosis / genetics
  • Amyotrophic Lateral Sclerosis / pathology*
  • Animals
  • Animals, Genetically Modified
  • Antisense Elements (Genetics) / genetics
  • Antisense Elements (Genetics) / toxicity*
  • Arginine
  • C9orf72 Protein
  • Cell Death / drug effects*
  • Cell Death / genetics
  • DNA Repeat Expansion / genetics
  • Dipeptides / toxicity*
  • Drosophila melanogaster
  • Frontotemporal Dementia / genetics
  • Frontotemporal Dementia / pathology*
  • Humans
  • Motor Neurons / drug effects
  • Motor Neurons / pathology
  • Neurons / drug effects*
  • Neurons / pathology*
  • Primary Cell Culture
  • Proline
  • Protein Aggregation, Pathological
  • Proteins / genetics
  • Spinal Cord / metabolism


  • Antisense Elements (Genetics)
  • C9orf72 Protein
  • C9orf72 protein, human
  • Dipeptides
  • Proteins
  • Arginine
  • Proline

Supplementary concepts

  • Frontotemporal Dementia With Motor Neuron Disease