University of Cambridge
Cambridge CB2 1LR
Office Phone: 01223 761128
The focus of my research is to develop Computational Morphodynamics models at the cellular level describing multicellular tissues such as the shoot apical meristem. The models are developed in close collaboration with experimental groups and describe the dynamics of gene regulatory networks, hormone transport and signalling, cell growth and division, and mechanical properties. Integral for the research is the iterative evaluation of the models and their parameters to new experimental data, mainly in the form of live microscopy data.
One focus is on the understanding of the development of new primordia at the periphery of the shoot apex, where the phytohormone auxin is focused to the sites where new organs form, and this is accomplished via an intricate feedback to its own transport. At the same time physical stresses can provide the required intercellular connection for the regulated transport. We also suggest that stresses are sensed when creating new fibers, such that primordia growth becomes regulated and correlated with the positioning. The models we develop hence require a mechanistic description of molecular reactions transport and signalling, physical stresses and growth, and the possibility of interactions in between.
Another problem we are studying is the regulation and plasticity of the cells in the shoot apical meristem, which keeps its general cell differentiation pattern throughout the life of a plant, even if the cells are replaced during the symplastic growth where cells are moving out of the meristem tissue. We have focused on developing models for gene regulation and intercellular signalling, where the experimentally known CLAVATA-WUSCHEL negative feedback provides the core of the network. We develop models and optimise and evaluate model parameters towards large sets of perturbation experiments, where our approach focus on regions of parameters to describe the model network behavior. Also of interest is the receptor cross-talk that is part of this regulatory system.
Selected recent publications
R.K. Yadav, M. Perales, J. Gruel, T. Girke, H. Jönsson, and G.V. Reddy (2011) WUSCHEL protein movement mediates stem cell homeostasis in the Arabidopsis shoot apex. Genes & Development 25:2025-2030.
P. Sahlin, P. Melke, and H. Jönsson (2011) Models of sequestration and receptor cross-talk for explaining multiple mutants in plant stem cell regulation. BMC Systems Biology 5:2
M. Heisler, O. Hamant, P. Krupinski, M. Uyttewaal, C. Ohno, H. Jönsson, J. Traas, E. Meyerowitz (2010) Alignment between PIN1 Polarity and Microtubule Orientation in the Shoot Apical Meristem Reveals a Tight Coupling between Morphogenesis and Auxin Transport. PLoS Biology 8(10):e1000516.
P. Sahlin, H. Jönsson (2010) A modeling study on how cell division affects properties of epithelial tissues under isotropic growth. PLoS ONE 5(7):e11750.
O. Hamant, M. Heisler, H. Jönsson, P. Krupinski, M. Uyttewaal, P. Bokov, F. Corson, P. Sahlin, A. Boudaoud, E. M. Meyerowitz, Y. Couder, and J. Traas (2008) Developmental patterning by mechanical signals in Arabidopsis. Science 322, 1650-1655.
H. Jönsson, M. Heisler, B.E. Shapiro, E.M. Meyerowitz, and E. Mjolsness (2006) An auxin-driven polarized transport model for phyllotaxis. Proceedings of the National Academy of Sciences USA 103, 1633-1638.
P. Krupinski and H. Jönsson (2010) Modeling auxin-regulated Development. Cold Spring Harb Persp Biol 2, a001560.
H. Jönsson and P. Krupinski (2010) Modeling plant growth and pattern formation. Current Opinion in Plant Biology 13,5-11.