image: Confocal fluorescence microscopy images of chimeric yeast-E. coli cells. Yeast cell wall was stained blue and bacterial rRNA was stained purple view more
Credit: Image courtesy of Paul Webster.
Researchers report a symbiotic relationship between Escherichia coli and yeast cells that provides insight into the origins of mitochondria in cells. The endosymbiotic theory holds that mitochondria, now an integral part of animal cells, including human cells, evolved from an independent bacterium that inserted itself into an archaeal cell more than a billion years ago, and developed a symbiotic relationship with the cell that was passed on to succeeding generations. Peter G. Schultz, Frantisek Supek, and colleagues sought to establish such a symbiotic relationship between E. coli and yeast cells by engineering deficiencies in each that could be offset by the other. Having created a yeast mutant with deficient mitochondria unable to produce ATP, the cellular energy currency, the authors inserted an E. coli bacterium that expressed the ADP/ATP translocase enzyme, enabling the yeast to grow on a nonfermentable medium. Additionally, the authors engineered the E. coli with a deficiency in thiamin that was offset by the yeast, as well as SNARE-like proteins to prevent bacterial clearance in the host. The authors found that the symbiotic E. coli-yeast chimera persisted for more than 40 generations. According to the authors, the symbiotic chimera model can provide a mechanism for further exploring the origins of mitochondrial endosymbiosis.
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Article #18-13143: "Engineering yeast endosymbionts as a step toward the evolution of mitochondria," by Angad Mehta et al.
MEDIA CONTACT: Peter G. Schultz, The Scripps Research Institute; California Institute for Biomedical Research, La Jolla, CA; tel: 858 784 9300; e-mail: schultz@calibr.org
Journal
Proceedings of the National Academy of Sciences