A team of synthetic biologists at Yale University has devised a way to ensure genetically modified organisms can be safely confined in the environment.
Design of multilayered genetic safeguards: riboregulation, engineered addiction, auxotrophy and supplemental repressors. Image credit: Ryan R. Gallagher et al.
The scientists, led by Dr Farren Isaacs of the Yale’s Department of Molecular, Cellular and Developmental Biology, rewrote the DNA of Escherichia coli so that it requires the presence of a special synthetic amino acid that does not exist in nature to activate genes essential for growth.
This new method of bio-containment, reported in Nature, solves a longstanding problem in biotechnology.
“This is a significant improvement over existing biocontainment approaches for genetically modified organisms. This work establishes important safeguards for organisms in agricultural settings, and more broadly, for their use in environmental bioremediation and even in medical therapies,” said Dr Isaacs, who is the senior author of the Nature paper.
Dr Isaacs and his collaborators call these new bacteria genomically recoded organisms (GROs) because they have a new genetic code devised by the scientists.
The new code allowed the team to link growth of Escherichia coli to synthetic amino acids not found in nature, establishing an important safeguard that limits the spread and survival of organisms in natural environments.
In a second study, reported in the Nucleic Acids Research, the biologists devised a strategy to layer multiple safeguards that also limit growth of genetically modified organisms (GMOs) to environments that contain a different set of synthetic molecules.
The scientists describe a complementary set of distinct and portable safeguards capable of securing a wide range of organisms. These safe GMOs will improve efficiency of such engineered organisms, which are now being used in closed systems, such as the production of pharmaceuticals, fuels, and new chemicals.
Concerns about use of GMOs in open environments, however, has limited their adoption in other areas.
“The new code paired with artificial amino acids will allow scientists to create safer GMOs for use in open systems, which include improved food production, designer probiotics to combat a host of diseases, and specialized microorganisms that clean up oil spills and landfills,” Dr Isaacs and his colleagues said.
“As synthetic biology leads to the emergence of more sophisticated GMOs to address these grand challenges, we must assume a proactive role in establishing safe and efficacious solutions for biotechnology, similar to those who worked to secure the Internet in the 1990s.”
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Alexis J. Rovner et al. Recoded organisms engineered to depend on synthetic amino acids. Nature, published online January 21, 2015; doi: 10.1038/nature14095
Ryan R. Gallagher et al. Multilayered genetic safeguards limit growth of microorganisms to defined environments. Nucl. Acids Res., published online January 7, 2015; doi: 10.1093/nar/gku1378
