title: Biocontainment of genetically modified organisms by synthetic protein design.
abstract: Genetically modified organisms (GMOs) are increasingly deployed at large scales and in open environments. Genetic biocontainment strategies are needed to prevent unintended proliferation of GMOs in natural ecosystems. Existing biocontainment methods are insufficient because they impose evolutionary pressure on the organism to eject the safeguard by spontaneous mutagenesis or horizontal gene transfer, or because they can be circumvented by environmentally available compounds. Here we computationally redesign essential enzymes in the first organism possessing an altered genetic code (Escherichia coli strain C321.ΔA) to confer metabolic dependence on non-standard amino acids for survival. The resulting GMOs cannot metabolically bypass their biocontainment mechanisms using known environmental compounds, and they exhibit unprecedented resistance to evolutionary escape through mutagenesis and horizontal gene transfer. This work provides a foundation for safer GMOs that are isolated from natural ecosystems by a reliance on synthetic metabolites.
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Mandell
authors.affiliation: 1] Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA [2] Program in Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Lajoie
authors.affiliation: 1] Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA [2] Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Mee
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takeuchi
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Gleb
authors.initials: G
authors.lastname: Kuznetsov
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Norville
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gregg
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: Barry L
authors.initials: BL
authors.lastname: Stoddard
authors.affiliation: 1] Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA [2] Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, USA.
authors.forename: George M
authors.initials: GM
authors.lastname: Church
mesh_terms: D000596:Amino Acids / Q000737:chemistry* / Q000378:metabolism*; D005075:Biological Evolution; D003062:Codon / Q000235:genetics; D003264:Containment of Biohazards / Q000379:methods*; D017753:Ecosystem; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D022761:Gene Transfer, Horizontal / Q000235:genetics; D020043:Genes, Essential / Q000235:genetics; D005815:Genetic Code / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods; D050296:Microbial Viability / Q000235:genetics; D009154:Mutation / Q000235:genetics; D030781:Organisms, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D012449:Safety; D012641:Selection, Genetic; D058615:Synthetic Biology / Q000379:methods*
chemical_list: D000596:Amino Acids; D003062:Codon; D029968:Escherichia coli Proteins