A yeast model of FUS/TLS-dependent cytotoxicity

PLoS Biol. 2011 Apr;9(4):e1001052. doi: 10.1371/journal.pbio.1001052. Epub 2011 Apr 26.

Abstract

FUS/TLS is a nucleic acid binding protein that, when mutated, can cause a subset of familial amyotrophic lateral sclerosis (fALS). Although FUS/TLS is normally located predominantly in the nucleus, the pathogenic mutant forms of FUS/TLS traffic to, and form inclusions in, the cytoplasm of affected spinal motor neurons or glia. Here we report a yeast model of human FUS/TLS expression that recapitulates multiple salient features of the pathology of the disease-causing mutant proteins, including nuclear to cytoplasmic translocation, inclusion formation, and cytotoxicity. Protein domain analysis indicates that the carboxyl-terminus of FUS/TLS, where most of the ALS-associated mutations are clustered, is required but not sufficient for the toxicity of the protein. A genome-wide genetic screen using a yeast over-expression library identified five yeast DNA/RNA binding proteins, encoded by the yeast genes ECM32, NAM8, SBP1, SKO1, and VHR1, that rescue the toxicity of human FUS/TLS without changing its expression level, cytoplasmic translocation, or inclusion formation. Furthermore, hUPF1, a human homologue of ECM32, also rescues the toxicity of FUS/TLS in this model, validating the yeast model and implicating a possible insufficiency in RNA processing or the RNA quality control machinery in the mechanism of FUS/TLS mediated toxicity. Examination of the effect of FUS/TLS expression on the decay of selected mRNAs in yeast indicates that the nonsense-mediated decay pathway is probably not the major determinant of either toxicity or suppression.

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
  • Cell Nucleus / genetics
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • Gene Expression Regulation
  • Mutation
  • Neurons / metabolism
  • RNA Helicases
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA-Binding Protein FUS / genetics*
  • RNA-Binding Protein FUS / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Trans-Activators / metabolism*

Substances

  • RNA, Messenger
  • RNA-Binding Protein FUS
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Trans-Activators
  • DNA Helicases
  • RNA Helicases
  • UPF1 protein, human
  • ECM32 protein, S cerevisiae