Prion propagation can occur in a prokaryote and requires the ClpB chaperone.
Bottom Line: Here, we demonstrate that E. coli can propagate the Sup35 prion under conditions that do not permit its de novo formation.Prion propagation in yeast requires Hsp104 (a ClpB ortholog), and prior studies have come to conflicting conclusions about ClpB's ability to participate in this process.Our demonstration of ClpB-dependent prion propagation in E. coli suggests that the cytoplasmic milieu in general and a molecular machine in particular are poised to support protein-based heredity in the bacterial domain of life.
Affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States Whitehead Institute for Biomedical Research, Cambridge, United States.Show MeSH
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Mentions: All R1 experimental and control colonies (20 of each) had lost pSC101TS-NEW1 or pSC101TS, respectively, as assessed by patching on selective medium (data not shown). Moreover, the absence of NEW1 DNA was confirmed by PCR (Figure 3C) and the absence of New1 protein was confirmed by Western blot analysis (Figure 3B). We detected SDS-stable Sup35 NM aggregates in 8 of 20 experimental samples (Figure 3B) and none of the control samples (Figure 3D). We selected 4 of the 8 aggregate-positive clones (Figure 3B, asterisks) to establish the four experimental lineages and arbitrarily selected four aggregate-negative control clones (Figure 3D, asterisks) to establish the four control lineages. 2 of the 4 experimental lineages (L1E and L3E) retained SDS-stable Sup35 NM aggregates throughout the course of the experiment (Figure 4A, Figure 4—figure supplement 1B). Of these two lineages, one maintained aggregates in 9 of 10 R4 clones (Figure 4A) and the other maintained aggregates in 7 of 10 R4 clones (Figure 4—figure supplement 1B). We conclude that SDS-stable Sup35 NM aggregates can be propagated in E. coli for at least ∼100 generations in the absence of New1 (Figure 5A).10.7554/eLife.02949.007Figure 4.E. coli can propagate the Sup35 NM prion over ∼100 generations.
Affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States Whitehead Institute for Biomedical Research, Cambridge, United States.