New Advances in Engineering a 'Wildly New Genome': The Limits of Genetic Reprogramming

Scientists have taken a leap forward when it comes to biotechnology. In two projects, they've created new genomes inside the bacterium E. coli in ways that test the limits of genetic reprogramming. The findings could increase the flexibility, productivity and safety in biotechnology.

In the first project, the researchers created a novel genome, the first-ever entirely genomically recoded organism, by replacing all 321 instances of a specific codon throughout the organism's entire genome with a "word" of supposedly identical meaning. They then reintroduced a reprogramed version of the original word (with a new meaning, a new amino acid) into the bacteria. This expanded the bacterium's "vocabulary" and allowed it to produce proteins that do not normally occur in nature.

That's not all the scientists accomplished, though. In the second project, the researchers removed every occurrence of 13 different codons across 42 separate E. coli genes, using a different organism for each gene, and replaced them with other codons of the same function. When they were done, 24 percent of the DNA across the 42 targeted genes had been changed, yet the proteins the genes produced remained identical to those produced by the original genes.

In fact, the researchers found that of the 13 codons chosen for the project, all could be changed. In theory, they could potentially replace any or all of those 13 codons throughout the entire genome. This, in turn, could have huge implications for future research.

So what exactly would recoded genomes do? They can confer protection against viruses, which limit productivity in the biotech industry. They can also help prevent the spread of potentially dangerous genetically engineered traits to wild organisms.

"In science we talk a lot about the 'what' and the 'how' of things, but in this case, the 'why' is very important," said George Church, one of the researchers, in a news release.

The findings could be huge for developing new treatments in the future. It could help with viruses and could even open up the way to new therapies.

"These results might also open a whole new chemical toolbox for biotech production," said Farren Isaacs, one of the researchers, in a news release. "For example, adding durable polymers to a therapeutic molecule could allow it to function longer in the human bloodstream."

The findings are published in the journal Science.