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Updated: May 4, 2026
High-throughput Screening for Protein-based Inheritance in S. cerevisiae
Published on: August 8, 2017
Direct assessment in bacteria of prionoid propagation and phenotype selection by Hsp70 chaperone
Fátima Gasset-Rosa1, Anne-Sophie Coquel, María Moreno-Del Álamo
1Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas - CSIC, C/ Ramiro de Maeztu 9, Madrid, E-28040, Spain.
Abstract:
Protein amyloid aggregates epigenetically determine either advantageous or proteinopathic phenotypes. Prions are infectious amyloidogenic proteins, whereas prionoids lack infectivity but spread from mother to daughter cells. While prion amyloidosis has been studied in yeast and mammalian cells models, the dynamics of transmission of an amyloid proteinopathy has not been addressed yet in bacteria. Using time-lapse microscopy and a microfluidic set-up, we have assessed in Escherichia coli the vertical transmission of the amyloidosis caused by the synthetic bacterial model prionoid RepA-WH1 at single cell resolution within their lineage context. We identify in vivo the coexistence of two strain-like types of amyloid aggregates within a genetically identical population and a controlled homogeneous environment. The amyloids are either toxic globular particles or single comet-shaped aggregates that split during cytokinesis and exhibit milder toxicity. Both segregate and propagate in sublineages, yet show interconversion. ClpB (Hsp104) chaperone, key for spreading of yeast prions, has no effect on the dynamics of the two RepA-WH1 aggregates. However, the propagation of the comet-like species is DnaK (Hsp70)-dependent. The bacterial RepA-WH1 prionoid thus provides key qualitative and quantitative clues on the biology of intracellular amyloid proteinopathies.
Insights
This study reveals two types of amyloid aggregates in bacteria, one toxic and one less so, which propagate differently within cell lineages. Bacterial prionoid dynamics offer new insights into intracellular amyloid proteinopathies.
Area of Science:
- Microbiology
- Molecular Biology
- Biophysics
Background:
- Protein amyloid aggregates can influence cell phenotypes, with prions and prionoids studied in yeast and mammals.
- Bacterial models for studying amyloid proteinopathy transmission dynamics are lacking.
Purpose of the Study:
- To investigate the vertical transmission of amyloid aggregates caused by the synthetic bacterial prionoid RepA-WH1 in Escherichia coli.
- To characterize the behavior and propagation of different amyloid aggregate types within bacterial lineages at single-cell resolution.
Main Methods:
- Utilized time-lapse microscopy and a microfluidic setup for observing Escherichia coli.
- Analyzed the transmission dynamics of RepA-WH1 amyloid aggregates within single-cell lineages.
- Investigated the roles of ClpB (Hsp104) and DnaK (Hsp70) chaperones in aggregate propagation.
Main Results:
- Identified two coexisting, strain-like types of RepA-WH1 amyloid aggregates in E. coli: toxic globular particles and less toxic comet-shaped aggregates.
- Observed that comet-shaped aggregates split during cell division and propagate in sublineages, with interconversion between types.
- Found that ClpB (Hsp104) did not affect aggregate dynamics, but DnaK (Hsp70) was essential for comet-shaped aggregate propagation.
Conclusions:
- The bacterial RepA-WH1 prionoid model provides a system to study intracellular amyloid proteinopathy transmission.
- Bacterial amyloid propagation exhibits distinct characteristics compared to yeast prions, with specific chaperone dependencies.
- These findings offer crucial insights into the qualitative and quantitative biology of intracellular amyloid proteinopathies.
