Computer-generated image of anaerobic, spore-forming, Clostridium bacteriaCDC, JAMES ARCHERResearchers at Harvard Medical School used software to run through roughly 60,000 bacterial genomes in search of proteins that, in yeast, would be predicted to behave as prions—that is, become misfolded in a way that passes on the errant structure to like proteins. In doing so, they identified a version of the global regulator Rho encoded in the genome of Clostridium botulinum, the causative agent of botulism. When they injected Cb-Rho into E. coli to examine the protein’s function, they found that the protein misfolded in a prion-like manner, rendering it nonfunctional and allowing genes normally suppressed by Rho to be expressed.
The study, published last week (January 13) in Science, is the first to identify a prion-like protein in bacteria, “suggesting that the emergence of prions predates the evolutionary split between eukaryotes and bacteria,” the authors, from Harvard Medical School, wrote.
Bacterial proteins capable of acting like prions could help the microbes to adapt to environmental changes. One of the genes liberated from Rho suppression, for example, allowed E. coli to better adapt to ethanol exposure. Because prions pass on their misfolded shape to like proteins, they may allow bacteria evolve without genomic changes. “Bacteria might need quick responses to their environment, such as dealing with antibiotics,” Peter Chien, a bacterial biochemist at the University of Massachusetts Amherst, who was not involved in the research, told ...
