Michigan State teamed up with MSP-Maastricht to develop a biocontainment system to accompany their engineered E. coli strain intended for establishment in the bovine rumen microbiome. Horizontal gene transfer is a critical concern in projects involving engineered gut symbionts as disruptions in the gut microbiome could lead to unforeseen consequences.

For this reason, our two teams worked together to plan a biocontainment strategy specific to the MSP-Maastricht iGEM team’s project. Our strategy makes use of the GhoST toxin-antitoxin system to lyse recipient bacteria, while antitoxin production prevents unintended lysis in the engineered symbiont. In this design, antitoxin expression is placed under the control of a hydrogen peroxide inducible promoter in order to cease antitoxin production and lyse the cell should it escape the cow gut. This provides protection both against physical escape and horizontal gene transfer while posing minimal burden to the cell.