Synthetic Biology
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Overlapping biocontainment strategies for genetically modified E. coli

Gallagher RR, Patel JR, et al. (2015) Multilayered genetic safeguards limit growth of microorganisms to defined environments. Nucleic Acids Res, 43(3): 1945–1954.

Genetically modified organisms (GMOs) are widely used for biotechnological production or transformation of valuable compounds. However, with increasing interest in open clinical and environmental applications, there is a heightened need for the generation of safeguards that would prevent these organisms’ ability to survive outside of controlled and confined settings.

In this featured article, Dr Farren Isaacs (Yale University) and his team have developed a system of overlapping safeguards to ensure that genetically engineered E. coli can still perform the desired manufacturing functions but cannot survive outside of an artificial environment that includes specific small molecules.

Among the approaches used, the lab engineered codon-optimized bacterial toxin genes, made using gBlocks® Gene Fragments, that would be expressed when a small molecule, such as tetracycline, is absent from the growth media.

Product focus: Custom dsDNA fragments

gBlocks® Gene Fragments are double-stranded, sequence-verified, DNA genomic blocks, 125–3000 bp in length, that can be shipped in 2–5 working days for affordable and easy gene construction or modification. These dsDNA fragments have been used in a wide range of applications including CRISPR-mediated genome editing, antibody research, codon optimization, mutagenesis, and aptamer expression. They can also be used for generating qPCR standards.

Learn more about gBlocks Gene Fragments at

Additional reading

DECODED Online newsletter articles—Written by scientists, these articles provide tips for conducting more effective experiments, and give overviews of the latest techniques and applications used in the field. They also include in depth research profiles and citation summaries that describe research done by your colleagues who already successfully using IDT products.


Review other DECODED Online newsletter articles on synthetic biology and genome editing applications.

You can also browse our DECODED Online newsletter for additional application reviews, lab tips, and citation summaries to facilitate your research.

Author: Hans Packer, PhD, is a scientific writer at IDT.

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gBlocks® Gene Fragments

Double-stranded DNA up to 3,000 kb—great for easy gene construction, CRISPR genome editing, and more.

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