Unknown

Dataset Information

0

Pre-amyloid oligomers of the proteotoxic RepA-WH1 prionoid assemble at the bacterial nucleoid.


ABSTRACT: Upon binding to short specific dsDNA sequences in vitro, the N-terminal WH1 domain of the plasmid DNA replication initiator RepA assembles as amyloid fibres. These are bundles of single or double twisted tubular filaments in which distorted RepA-WH1 monomers are the building blocks. When expressed in Escherichia coli, RepA-WH1 triggers the first synthetic amyloid proteinopathy in bacteria, recapitulating some of the features of mammalian prion diseases: it is vertically transmissible, albeit non-infectious, showing up in at least two phenotypically distinct and interconvertible strains. Here we report B3h7, a monoclonal antibody specific for oligomers of RepA-WH1, but which does not recognize the mature amyloid fibres. Unlike a control polyclonal antibody generated against the soluble protein, B3h7 interferes in vitro with DNA-promoted or amyloid-seeded assembly of RepA-WH1 fibres, thus the targeted oligomers are on-pathway amyloidogenic intermediates. Immuno-electron microscopy with B3h7 on thin sections of E. coli cells expressing RepA-WH1 consistently labels the bacterial nucleoid, but not the large cytoplasmic aggregates of the protein. This observation points to the nucleoid as the place where oligomeric amyloid precursors of RepA-WH1 are generated, and suggests that, once nucleated by DNA, further growth must continue in the cytoplasm due to entropic exclusion.

SUBMITTER: Moreno-Del Alamo M 

PROVIDER: S-EPMC4589793 | biostudies-other | 2015

REPOSITORIES: biostudies-other

Similar Datasets

| S-EPMC3021675 | biostudies-literature
| S-EPMC5075897 | biostudies-other
| S-EPMC2766818 | biostudies-literature
| S-EPMC5515880 | biostudies-literature
| S-EPMC7275774 | biostudies-literature
| S-EPMC2573087 | biostudies-other
| S-EPMC6497057 | biostudies-literature
| S-EPMC2853175 | biostudies-literature
| S-EPMC7202931 | biostudies-literature
| S-EPMC6631858 | biostudies-literature