Abstract

Living cells often break symmetry and adopt a preferential direction, which is known as cell polarity. This process is fundamental in yeast, plant and animal cells in a wide variety of contexts [1].

In the case of plants, it has been shown that cell polarity of PIN proteins is key for a wide variety of patterns, ranging from the arrangement of leaves and flowers around the shoot [2], to vein formation in leaves [3].

Recently, at the Sainsbury Laboratory (SLCU) we have found that plant cell cultures expressing a tagged fluorescence PIN reporter can show different spatio-temporal stochastic fluctuations of PIN in the cell membrane, and that such cells can exhibit PIN polarity even being isolated, with no direct cell-to-cell interactions (unpublished).

This project will consist of studying how dynamic stochastic fluctuations can make cells spontaneously polarise, in a model where PIN polarity can occur when cells are isolated (see deterministic models in [1, 4] or simplified versions of it, e.g. see models in [5]). Stochastic dynamics will be implemented through Chemical Langevin Equations [6] with the Organism and Tissue software, which have been developed at the Jönsson Lab. There will be also the possibility to analytically study the different models through linear stability analysis [7] and local perturbation analysis [5]. Ultimately, this project will help to develop a better understanding of the nature of the observed PIN spatio-temporal fluctuations in our cell cultures. This project will be developed at the SLCU , within the Jönsson, Locke and Meyerowitz groups.

1. Abley K, De Reuille PB, Strutt D, et al (2013) An intracellular partitioning-based framework for tissue cell polarity in plants and animals. Development 140:2061–2074. doi: doi:10.1242/dev.062984
2. Jönsson H, Heisler MG, Shapiro BE, et al (2006) An auxin-driven polarized transport model for phyllotaxis. Proc Natl Acad Sci U S A 103 :1633–1638.
3. Rolland-Lagan A, Prusinkiewicz P (2005) Reviewing models of auxin canalization in the context of leaf vein pattern formation in Arabidopsis. Plant J 44 :854–865.
4. Abley K, Sauret-gueto S, Marée AFM , Coen E (2016) Formation of Polarity Convergences underlying Shoot Outgrowths. 1–60. doi: 10.7554/eLife.18165
5. Edelstein-keshet L, Holmes WR, Zajac M, et al (2013) From simple to detailed models for cell polarization. 368:
6. Gillespie DT (2000) The chemical Langevin equation The chemical Langevin equation. 297:297–306. doi: 10.1063/1.481811
7. Fàbregas N, Formosa-Jordan P, Confraria A, et al (2015) Auxin Influx Carriers Control Vascular Patterning and Xylem Differentiation in Arabidopsis thaliana. PLoS Genet 11:e1005183. doi: 10.1371/journal.pgen.1005183