Engineering yeast endosymbionts as a step toward the evolution of mitochondria

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TitleEngineering yeast endosymbionts as a step toward the evolution of mitochondria
Publication TypeJournal Article
Year of Publication2018
AuthorsMehta AP, Supekova L, Chen JH, Pestonjamasp K, Webster P, Ko Y, Henderson SC, McDermott G, Supek F, Schultz PG
Journal TitleProc Natl Acad Sci U S A
Journal DateOct 29
ISBN Number1091-6490 (Electronic)0027-8424 (Linking)
Accession Number30373839
KeywordsADP/ATP translocase, endosymbiotic theory, evolution, Mitochondria

It has been hypothesized that mitochondria evolved from a bacterial ancestor that initially became established in an archaeal host cell as an endosymbiont. Here we model this first stage of mitochondrial evolution by engineering endosymbiosis between Escherichia coli and Saccharomyces cerevisiae An ADP/ATP translocase-expressing E. coli provided ATP to a respiration-deficient cox2 yeast mutant and enabled growth of a yeast-E. coli chimera on a nonfermentable carbon source. In a reciprocal fashion, yeast provided thiamin to an endosymbiotic E. coli thiamin auxotroph. Expression of several SNARE-like proteins in E. coli was also required, likely to block lysosomal degradation of intracellular bacteria. This chimeric system was stable for more than 40 doublings, and GFP-expressing E. coli endosymbionts could be observed in the yeast by fluorescence microscopy and X-ray tomography. This readily manipulated system should allow experimental delineation of host-endosymbiont adaptations that occurred during evolution of the current, highly reduced mitochondrial genome.