title: A switchable light-input, light-output system modelled and constructed in yeast.
abstract: BACKGROUND
  Advances in synthetic biology will require spatio-temporal regulation of biological processes in heterologous host cells. We develop a light-switchable, two-hybrid interaction in yeast, based upon the Arabidopsis proteins PHYTOCHROME A and FAR-RED ELONGATED HYPOCOTYL 1-LIKE. Light input to this regulatory module allows dynamic control of a light-emitting LUCIFERASE reporter gene, which we detect by real-time imaging of yeast colonies on solid media.
  
  
  RESULTS
  The reversible activation of the phytochrome by red light, and its inactivation by far-red light, is retained. We use this quantitative readout to construct a mathematical model that matches the system's behaviour and predicts the molecular targets for future manipulation.
  
  
  CONCLUSIONS
  Our model, methods and materials together constitute a novel system for a eukaryotic host with the potential to convert a dynamic pattern of light input into a predictable gene expression response. This system could be applied for the regulation of genetic networks - both known and synthetic.
authors.affiliation: Institute of Molecular Plant Sciences, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JH, UK.
authors.forename: Oxana
authors.initials: O
authors.lastname: Sorokina
authors.affiliation: Institute of Plant Biology, Biological Research Center, Temesvari krt. 62, H-6726, Szeged, Hungary.
authors.forename: Anita
authors.initials: A
authors.lastname: Kapus
authors.affiliation: Institute of Plant Biology, Biological Research Center, Temesvari krt. 62, H-6726, Szeged, Hungary.
authors.forename: Kata
authors.initials: K
authors.lastname: Terecskei
authors.affiliation: Institute of Molecular Plant Sciences, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JH, UK.|Centre for Systems Biology at Edinburgh, C.H. Waddington Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JD, UK.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Dixon
authors.affiliation: Institute of Plant Biology, Biological Research Center, Temesvari krt. 62, H-6726, Szeged, Hungary.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Kozma-Bognar
authors.affiliation: Institute of Molecular Plant Sciences, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JH, UK.|Institute of Plant Biology, Biological Research Center, Temesvari krt. 62, H-6726, Szeged, Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Nagy
authors.affiliation: Institute of Molecular Plant Sciences, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JH, UK.|Centre for Systems Biology at Edinburgh, C.H. Waddington Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JD, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millar