title: Prediction of photoperiodic regulators from quantitative gene circuit models.
abstract: Photoperiod sensors allow physiological adaptation to the changing seasons. The prevalent hypothesis is that day length perception is mediated through coupling of an endogenous rhythm with an external light signal. Sufficient molecular data are available to test this quantitatively in plants, though not yet in mammals. In Arabidopsis, the clock-regulated genes CONSTANS (CO) and FLAVIN, KELCH, F-BOX (FKF1) and their light-sensitive proteins are thought to form an external coincidence sensor. Here, we model the integration of light and timing information by CO, its target gene FLOWERING LOCUS T (FT), and the circadian clock. Among other predictions, our models show that FKF1 activates FT. We demonstrate experimentally that this effect is independent of the known activation of CO by FKF1, thus we locate a major, novel controller of photoperiodism. External coincidence is part of a complex photoperiod sensor: modeling makes this complexity explicit and may thus contribute to crop improvement.
authors.affiliation: Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: José Domingo
authors.initials: JD
authors.lastname: Salazar
authors.forename: Treenut
authors.initials: T
authors.lastname: Saithong
authors.forename: Paul E
authors.initials: PE
authors.lastname: Brown
authors.forename: Julia
authors.initials: J
authors.lastname: Foreman
authors.forename: James C W
authors.initials: JC
authors.lastname: Locke
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Halliday
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: Carré
authors.forename: David A
authors.initials: DA
authors.lastname: Rand
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millar
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D001683:Biological Clocks; D004268:DNA-Binding Proteins / Q000235:genetics; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D008957:Models, Genetic; D017440:Photoperiod; D014157:Transcription Factors / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C418905:FT protein, Arabidopsis; D014157:Transcription Factors