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Expositor: Jacques Dumais Facultad de Ingeniería y Ciencias Universidad Adolfo Ibáñez Viña del Mar
Viernes 9 de noviembre, 16 h Av. Blanco Encalada 2008, 3er piso sala de seminarios The division of eukaryotic cells involves the assembly of complex cytoskeletal structures to exert the forces required for chromosome segregation and cytokinesis. In plants, tensional forces within the cytoskeleton appear to constrain cells to divide according to a small number of area minimizing configurations. We have shown that the probability of observing a particular division configuration increases inversely with its relative area according to an exponential probability distribution known as the Gibbs measure. The distribution is universal up to experimental accuracy with a unique constant that applies for all plants studied irrespective of the shape and size of their cells. Using a maximum entropy formulation, we were able to demonstrate that the empirically derived division rule is predicted by the dynamics of the tense cytoskeletal elements controlling the positioning of the division plane. Finally, by framing this division rule as a dynamical system we were able to identify several attractors that are predictive of characteristic cell patterns observed in plants. Plant cell division thus offers a remarkable example of how simple mechanical interactions at the subcellular level can lead to subtle behaviors at the cellular or multicellular levels. |
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