title: Construction of a genetic multiplexer to toggle between chemosensory pathways in Escherichia coli.
abstract: 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.
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
authors.forename: Tae Seok
authors.initials: TS
authors.lastname: Moon
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Clarke
authors.forename: Eli S
authors.initials: ES
authors.lastname: Groban
authors.forename: Alvin
authors.initials: A
authors.lastname: Tamsir
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Clark
authors.forename: Matthew
authors.initials: M
authors.lastname: Eames
authors.forename: Tanja
authors.initials: T
authors.lastname: Kortemme
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Voigt
mesh_terms: D001089:Arabinose / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics; D002633:Chemotaxis / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005838:Genotype; D019426:Integrases / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D000072236:Methyl-Accepting Chemotaxis Proteins; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; C489103:CheW protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C081956:fimB protein, E coli; C081955:fimE protein, E coli; C000607604:tsr protein, E coli; D001089:Arabinose; D019426:Integrases