title: Light-responsive control of bacterial gene expression: precise triggering of the lac promoter activity using photocaged IPTG.
abstract: Light can be used to control numerous cellular processes including protein function and interaction as well as gene expression in a non-invasive fashion and with unprecedented spatiotemporal resolution. However, for chemical phototriggers tight, gradual, and homogeneous light response has never been attained in living cells. Here, we report on a light-responsive bacterial T7 RNA polymerase expression system based on a photocaged derivative of the inducer molecule isopropyl-β-d-thiogalactopyranoside (IPTG). We have comparatively analyzed different Escherichia coli lac promoter-regulated expression systems in batch and microfluidic single-cell cultivation. The lacY-deficient E. coli strain Tuner(DE3) harboring additional plasmid-born copies of the lacI gene exhibited a sensitive and defined response to increasing IPTG concentrations. Photocaged IPTG served as a synthetic photo-switch to convert the E. coli system into an optogenetic expression module allowing for precise and gradual light-triggering of gene expression as demonstrated at the single cell level.
authors.affiliation: Institute of Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Research Center Jülich, Germany. k.-e.jaeger@fz-juelich.de t.drepper@fz-juelich.de.
authors.forename: Dennis
authors.initials: D
authors.lastname: Binder
authors.forename: Alexander
authors.initials: A
authors.lastname: Grünberger
authors.forename: Anita
authors.initials: A
authors.lastname: Loeschcke
authors.forename: Christopher
authors.initials: C
authors.lastname: Probst
authors.forename: Claus
authors.initials: C
authors.lastname: Bier
authors.forename: Jörg
authors.initials: J
authors.lastname: Pietruszka
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wiechert
authors.forename: Dietrich
authors.initials: D
authors.lastname: Kohlheyer
authors.forename: Karl-Erich
authors.initials: KE
authors.lastname: Jaeger
authors.forename: Thomas
authors.initials: T
authors.lastname: Drepper
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D023281:Genomics; D007091:Image Processing, Computer-Assisted; D007544:Isopropyl Thiogalactoside / Q000737:chemistry*; D007763:Lac Operon; D008027:Light; D046210:Microfluidic Analytical Techniques; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D027981:Symporters / Q000378:metabolism; D013997:Time Factors; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D001547:Benzaldehydes; D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D009004:Monosaccharide Transport Proteins; D027981:Symporters; D014764:Viral Proteins; D007544:Isopropyl Thiogalactoside; C064767:6-nitropiperonal; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases