Enabling stop codon read-through translation in bacteria as a probe for amyloid aggregation

Sci Rep. 2017 Sep 19;7(1):11908. doi: 10.1038/s41598-017-12174-0.

Abstract

Amyloid aggregation of the eukaryotic translation terminator eRF3/Sup35p, the [PSI +] prion, empowers yeast ribosomes to read-through UGA stop codons. No similar functional prion, skipping a stop codon, has been found in Escherichia coli, a fact possibly due to the efficient back-up systems found in bacteria to rescue non-stop complexes. Here we report that engineering hydrophobic amyloidogenic repeats from a synthetic bacterial prion-like protein (RepA-WH1) into the E. coli releasing factor RF1 promotes its aggregation and enables ribosomes to continue with translation through a premature UAG stop codon located in a β-galactosidase reporter. To our knowledge, intended aggregation of a termination factor is a way to overcome the bacterial translation quality checkpoint that had not been reported so far. We also show the feasibility of using the amyloidogenic RF1 chimeras as a reliable, rapid and cost-effective system to screen for molecules inhibiting intracellular protein amyloidogenesis in vivo, by testing the effect on the chimeras of natural polyphenols with known anti-amyloidogenic properties. Resveratrol exhibits a clear amyloid-solubilizing effect in this assay, showing no toxicity to bacteria or interference with the enzymatic activity of β-galactosidase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / genetics*
  • Codon, Terminator / genetics*
  • Drug Evaluation, Preclinical
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / genetics*
  • Gene Expression Regulation, Bacterial
  • Peptide Termination Factors / genetics*
  • Polyphenols / pharmacology
  • Protein Aggregates / drug effects
  • Protein Biosynthesis
  • Protein Engineering
  • Recombinant Fusion Proteins / genetics
  • Ribosomes / genetics

Substances

  • Amyloid
  • Codon, Terminator
  • Escherichia coli Proteins
  • Peptide Termination Factors
  • Polyphenols
  • Protein Aggregates
  • Recombinant Fusion Proteins
  • prfA protein, E coli