The “Marionette” Family of E.Coli Cell Lines


This tangible property is a set of E.coli strains with a variety of cellular circuits that has applications as a research tool in synthetic biology and cellular engineering.

Problem Addressed

Cells have complex circuitry capable of sensing and responding to stimuli. Cellular engineering harnesses and refines intrinsic cellular circuitry to create cells capable of responding to pre-determined stimuli in useful ways. A major hindrance to cellular engineering lies in creating circuits that are robust and multiplexed. Cellular circuits often suffer from poor dynamic range due to high background or poor induction. Additionally, there are only a few inducer/output pairs that are currently available.


These inventors used a combination of rational engineering and positive/negative selection techniques to create new and improved circuit pairs from transcription factors with small molecule inducers. After this modification, the transcription factors displayed lower levels of background signal and/or increased sensitivity to inducer. Next, the inventors multiplexed these inducer/output pairs to create “Marionette” E.coli strains with up to 12 discrete genetic outputs. The “Marionette” E.coli strains achieve an impressive dynamic range of >100 fold activation of each output when induced with its cognate inducer, and <2 fold crosstalk with other inducers.


  • E.coli strains with up to 12 genetic input/output pairs
  • Excellent dynamic range with >100 fold activation and <2 fold cross talk