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Modelling cell fate assignment in the Arabidopsis root epidermis

Nick Monk
CPIB, University of Nottingham, UK
le 06/03/2009 à 14:15

Résumé

The patterning of the Arabidopsis root epidermis depends on a genetic regulatory network that operates both within and between cells. Genetic studies have identified a number of key components of this network, but the functional logic of the network has remained unclear. In this talk, I will show how the genetic and biochemical data can be integrated in a novel modelling formalism that allows an exploration of both the sufficiency of known network interactions and the extent to which additional assumptions about the model can account for wild type and mutant data. Our new model shows that an existing hypothesis concerning the auto-regulation of WEREWOLF does not account fully for the expression patterns of components of the network, a prediction that we have confirmed experimentally in transgenic plants. Rather, our modelling suggests that patterning depends critically on the directed movement of the CAPRICE and GLABRA3 transcriptional regulators between epidermal cells. These movements underlie a novel mechanism for pattern formation in planar groups of cells, centred on mutual support of two cell fates rather than diffusion-driven local activation and lateral inhibition.