title: A competitive complex formation mechanism underlies trichome patterning on Arabidopsis leaves.
abstract: Trichome patterning in Arabidopsis serves as a model system for de novo pattern formation in plants. It is thought to typify the theoretical activator-inhibitor mechanism, although this hypothesis has never been challenged by a combined experimental and theoretical approach. By integrating the key genetic and molecular data of the trichome patterning system, we developed a new theoretical model that allows the direct testing of the effect of experimental interventions and in the prediction of patterning phenotypes. We show experimentally that the trichome inhibitor TRIPTYCHON is transcriptionally activated by the known positive regulators GLABRA1 and GLABRA3. Further, we demonstrate by particle bombardment of protein fusions with GFP that TRIPTYCHON and CAPRICE but not GLABRA1 and GLABRA3 can move between cells. Finally, theoretical considerations suggest promoter swapping and basal overexpression experiments by means of which we are able to discriminate three biologically meaningful variants of the trichome patterning model. Our study demonstrates that the mutual interplay between theory and experiment can reveal a new level of understanding of how biochemical mechanisms can drive biological patterning processes.
authors.affiliation: Department of Botany III, Botanical Institute, University of Cologne, Cologne, Germany.
authors.forename: Simona
authors.initials: S
authors.lastname: Digiuni
authors.forename: Swen
authors.initials: S
authors.lastname: Schellmann
authors.forename: Florian
authors.initials: F
authors.lastname: Geier
authors.forename: Bettina
authors.initials: B
authors.lastname: Greese
authors.forename: Martina
authors.initials: M
authors.lastname: Pesch
authors.forename: Katja
authors.initials: K
authors.lastname: Wester
authors.forename: Burcu
authors.initials: B
authors.lastname: Dartan
authors.forename: Valerie
authors.initials: V
authors.lastname: Mach
authors.forename: Bhylahalli Purushottam
authors.initials: BP
authors.lastname: Srinivas
authors.forename: Jens
authors.initials: J
authors.lastname: Timmer
authors.forename: Christian
authors.initials: C
authors.lastname: Fleck
authors.forename: Martin
authors.initials: M
authors.lastname: Hulskamp