Genome Editing

An organism’s genetic code now comes with search-and-replace capabilities. The new technique, developed by researchers at Harvard and Yale Universities, has led to virus-resistant bacteria, with the potential to use the modified organisms to produce entirely new compounds.

Large-scale editing of an organism’s genetic information—known as its genome—was almost a decade in the making. This first-of-a-kind demonstration paves the way for scientists to design custom organisms with unique and useful capabilities.

Editing for Virus Resistance

More immediately, the research—headed by Farren Isaacs, Ph.D., at Yale University and co-author George Church, Ph.D., at Harvard Medical School—is beneficial for the biotechnology industry, which uses large vats of microorganisms to manufacture products like drugs and fuels.

Unfortunately, like humans, these tiny living factories are prone to disease. Viruses infect up to 50 percent of the organisms in industrial vats, which lowers both productivity and efficiency. Making changes across the organism’s entire genome, though, can help keep the process going by preventing the virus from using the bacteria’s cellular machinery to reproduce.

"We show that we can basically engineer an organism with an increased resistance to viruses," says Isaacs. "That alone is actually quite significant because we show that making some fundamental changes to the genetic code can lead to virus resistance."

Building Better Micro-Factories

The new technique also freed up one small segment of DNA—known as a codon—for use in an entirely different way. The repurposed codon could potentially allow the bacteria Escherichia coli to create compounds using unique amino acids that are not found in nature.

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"E. coli will have the ability to produce and evolve new proteins composed entirely of unnatural building blocks," says Chang Liu, Ph.D., a professor of biomedical engineering at the University of California, Irvine, who was not part of this study. "The possibilities for new enzymes and drugs are endless."

The new method is described in two articles published this week in the journal Science.

Reprogramming Other Organisms

One of the advantages of this method is that it targets the genetic code, which basically works the same way in all organisms. Does that mean we might one day see editing of more complex organisms like plants, fish, or even humans?

"The kind of changes that we have made in E. coli could, in principle, be made in other organisms, as well," says Isaacs. "But that really is non-trivial to do."

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The process has been optimized for use in E. coli, though the researchers are looking for ways to use the technique to modify other bacteria or organisms.

The most direct benefit to humans will likely come from the tireless efforts of factory-capable bacteria. These modified, but efficient, workers will not only be resistant to viruses, but will also be capable of creating as yet undreamed of drug compounds.