CGG repeat-associated translation mediates neurodegeneration in fragile X tremor ataxia syndrome.

Journal Article (Journal Article)

Fragile X-associated tremor ataxia syndrome (FXTAS) results from a CGG repeat expansion in the 5' UTR of FMR1. This repeat is thought to elicit toxicity as RNA, yet disease brains contain ubiquitin-positive neuronal inclusions, a pathologic hallmark of protein-mediated neurodegeneration. We explain this paradox by demonstrating that CGG repeats trigger repeat-associated non-AUG-initiated (RAN) translation of a cryptic polyglycine-containing protein, FMRpolyG. FMRpolyG accumulates in ubiquitin-positive inclusions in Drosophila, cell culture, mouse disease models, and FXTAS patient brains. CGG RAN translation occurs in at least two of three possible reading frames at repeat sizes ranging from normal (25) to pathogenic (90), but inclusion formation only occurs with expanded repeats. In Drosophila, CGG repeat toxicity is suppressed by eliminating RAN translation and enhanced by increased polyglycine protein production. These studies expand the growing list of nucleotide repeat disorders in which RAN translation occurs and provide evidence that RAN translation contributes to neurodegeneration.

Full Text

Duke Authors

Cited Authors

  • Todd, PK; Oh, SY; Krans, A; He, F; Sellier, C; Frazer, M; Renoux, AJ; Chen, K-C; Scaglione, KM; Basrur, V; Elenitoba-Johnson, K; Vonsattel, JP; Louis, ED; Sutton, MA; Taylor, JP; Mills, RE; Charlet-Berguerand, N; Paulson, HL

Published Date

  • May 8, 2013

Published In

Volume / Issue

  • 78 / 3

Start / End Page

  • 440 - 455

PubMed ID

  • 23602499

Pubmed Central ID

  • PMC3831531

Electronic International Standard Serial Number (EISSN)

  • 1097-4199

Digital Object Identifier (DOI)

  • 10.1016/j.neuron.2013.03.026


  • eng

Conference Location

  • United States