Engineering yeast endosymbionts as a step toward the evolution of mitochondria
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Endosymbiotic theory suggests that mitochondria evolved from free-living prokaryotes which entered the host cell and were retained as endosymbionts. Here, we model this earliest stage of the endosymbiotic theory of mitochondrial evolution by engineering endosymbiosis between two genetically tractable model organisms, Escherichia coli and Saccharomyces cerevisiae. In this model system, we engineered E. coli strains to survive in the yeast cytosol and provide ATP to a respiration-deficient yeast mutant. In a reciprocal fashion, yeast provided thiamin to an endosymbiotic E. coli thiamin auxotroph. This readily manipulated chimeric system was stable for more than 40 doublings and should allow us to investigate various aspects of the endosymbiotic theory of mitochondrial evolution.
Read the full article in PNAS