Construction of a genetic multiplexer to toggle between chemosensory pathways in Escherichia coli

Tae Seok Moon, Elizabeth J. Clarke, Eli S. Groban, Alvin Tamsir, Ryan M. Clark, Matthew Eames, Tanja Kortemme, Christopher A. Voigt

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


Many applications require cells to switch between discrete phenotypic states. Here, we harness the FimBE inversion switch to flip a promoter, allowing expression to be toggled between two genes oriented in opposite directions. The response characteristics of the switch are characterized using two-color cytometry. This switch is used to toggle between orthogonal chemosensory pathways by controlling the expression of CheW and CheW*, which interact with the Tar (aspartate) and Tsr* (serine) chemoreceptors, respectively. CheW* and Tsr* each contain a mutation at their protein-protein interface such that they interact with each other. The complete genetic program containing an arabinose-inducible FimE controlling CheW/CheW* (and constitutively expressed tar/tsr*) is transformed into an Escherichia coli strain lacking all native chemoreceptors. This program enables bacteria to swim toward serine or aspartate in the absence or in the presence of arabinose, respectively. Thus, the program functions as a multiplexer with arabinose as the selector. This demonstrates the ability of synthetic genetic circuits to connect to a natural signaling network to switch between phenotypes.

Original languageEnglish
Pages (from-to)215-227
Number of pages13
JournalJournal of Molecular Biology
Issue number2
StatePublished - Feb 18 2011


  • GFP
  • NSF
  • National Science Foundation
  • RBS
  • RFP
  • green fluorescent protein
  • red fluorescent protein
  • ribosome binding site


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