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Rational Design of Evolutionarily Stable Microbial Kill Switches.

ABSTRACT: The evolutionary stability of synthetic genetic circuits is key to both the understanding and application of genetic control elements. One useful but challenging situation is a switch between life and death depending on environment. Here are presented "essentializer" and "cryodeath" circuits, which act as kill switches in Escherichia coli. The essentializer element induces cell death upon the loss of a bi-stable cI/Cro memory switch. Cryodeath makes use of a cold-inducible promoter to express a toxin. We employ rational design and a toxin/antitoxin titering approach to produce and screen a small library of potential constructs, in order to select for constructs that are evolutionarily stable. Both kill switches were shown to maintain functionality in vitro for at least 140 generations. Additionally, cryodeath was shown to control the growth environment of a population, with an escape frequency of less than 1 in 10⁵ after 10 days of growth in the mammalian gut.

SUBMITTER: Stirling F

PROVIDER: S-EPMC5812007 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Rational Design of Evolutionarily Stable Microbial Kill Switches.

Stirling Finn F Bitzan Lisa L O'Keefe Samuel S Redfield Elizabeth E Oliver John W K JWK Way Jeffrey J Silver Pamela A PA

Molecular cell 20171101 4

The evolutionary stability of synthetic genetic circuits is key to both the understanding and application of genetic control elements. One useful but challenging situation is a switch between life and death depending on environment. Here are presented "essentializer" and "cryodeath" circuits, which act as kill switches in Escherichia coli. The essentializer element induces cell death upon the loss of a bi-stable cI/Cro memory switch. Cryodeath makes use of a cold-inducible promoter to express a ...[more]

PMID: 29149596

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