A DNA-promoted amyloid proteinopathy in Escherichia coli

作者：Elena Fernandez Tresguerres M; Moreno Diaz de la Espina Susana; Gasset Rosa Fatima; Giraldo Rafael^*

来源：Molecular Microbiology, 2010, 77(6): 1456-1469.

DOI：10.1111/j.1365-2958.2010.07299.x

P>Protein amyloids arise from the conformational conversion and assembly of a soluble protein into fibrilar aggregates with a crossed beta-sheet backbone. Amyloid aggregates are able to replicate by acting as a template for the structural transformation and accretion of further protein molecules. In physicochemical terms, amyloids arguably constitute the simplest self-replicative macromolecular assemblies. Similarly to the mammalian proteins PrP and alpha-synuclein, the winged-helix dimerization (WH1) domain of the bacterial, plasmid-encoded protein RepA can assemble into amyloid fibres upon binding to DNA in vitro. Here we report that a hyper-amyloidogenic functional variant (A31V) of RepA, fused to a red fluorescent protein, causes an amyloid proteinopathy in Escherichia coli with the following features: (i) in the presence of multiple copies of the specific DNA sequence opsp, WH1(A31V) accumulates as cytoplasmatic inclusions segregated from the nucleoid; (ii) such aggregates are amyloid in nature; (iii) bacteria carrying the amyloid inclusions age, exhibiting a fivefold expanded generation time; (iv) before cytokinesis, small inclusions are assembled de novo and transferred to the daughter cells, in which transmission failures cure amyloidosis; and (v) in the absence of inducer DNA, purified cellular WH1(A31V) inclusions seed amyloid fibre growth in vitro from the soluble protein. RepA-WH1 is a suitable bacterial model system for amyloid proteinopathies.

• 出版日期2010-9