Identification of genetic modifiers of TDP-43 neurotoxicity in Drosophila

PLoS One. 2013;8(2):e57214. doi: 10.1371/journal.pone.0057214. Epub 2013 Feb 27.

Abstract

Cytosolic aggregation of the nuclear RNA-binding protein TDP-43 is a histopathologic signature of degenerating neurons in amyotrophic lateral sclerosis (ALS), and mutations in the TARDBP gene encoding TDP-43 cause dominantly inherited forms of this condition. To understand the relationship between TDP-43 misregulation and neurotoxicity, we and others have used Drosophila as a model system, in which overexpression of either wild-type TDP-43 or its ALS-associated mutants in neurons is sufficient to induce neurotoxicity, paralysis, and early death. Using microarrays, we have examined gene expression patterns that accompany TDP-43-induced neurotoxicity in the fly system. Constitutive expression of TDP-43 in the Drosophila compound eye elicited widespread gene expression changes, with strong upregulation of cell cycle regulatory genes and genes functioning in the Notch intercellular communication pathway. Inducible expression of TDP-43 specifically in neurons elicited significant expression differences in a more restricted set of genes. Genes that were upregulated in both paradigms included SpindleB and the Notch target Hey, which appeared to be a direct TDP-43 target. Mutations that diminished activity of Notch or disrupted the function of downstream Notch target genes extended the lifespan of TDP-43 transgenic flies, suggesting that Notch activation was deleterious in this model. Finally, we showed that mutation of the nucleoporin Nup50 increased the lifespan of TDP-43 transgenic flies, suggesting that nuclear events contribute to TDP-43-dependent neurotoxicity. The combined findings identified pathways whose deregulation might contribute to TDP-43-induced neurotoxicity in Drosophila.

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Apoptosis
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / toxicity*
  • Drosophila / drug effects*
  • Drosophila / genetics
  • Nervous System / drug effects*
  • Nervous System / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / toxicity*

Substances

  • DNA-Binding Proteins
  • RNA-Binding Proteins

Grants and funding

The authors have no support or funding to report.