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Lundi 8 septembre 2014 14:00 - Duree : 1 heure
Lieu : Conference room - LIPhy - Bât E - 140 Avenue de la Physique - St Martin d’Hères. Accès par interphone, appeler le secrétariat

Orateur : Guy BLANCHARD

One of the promises for developmental biology of automated methods that concurrently measure the dynamics of cell shapes and quantify protein fluorescence has been that they will help us understand the physics of developing tissues. Myosin motor fluorescence could be a useful proxy for contractile force, but while the force exerted by individual myosin motors is known, the effective behaviour of large actomyosin aggregates is likely to be more complicated. Furthermore, it is also not yet clear what kind of mechanical model, relating forces to deformation rates, is appropriate for epithelial tissues.

In order to unravel these issues, we measured detailed apical myosin fluorescence and cell shape evolution across the amnioserosa tissue in many Drosophila embryos. We established which combinations of measurable parameters, such as myosin, rate of change of myosin, cell strain and neighbouring cell influences, yielded a mechanical model that best predicted cell deformation rates. Evaluating the success of non-invasive mechanical models has been problematic, so we propose a new morphogenetic forecasting paradigm. As in weather forecasting, starting from the same initial conditions, the quality of fit between (modelled) forecast and real data is assessed by a forecast window, the length of time over which a good fit is achieved.

I will summarise preliminary results on the relationship between myosin fluorescence and contractile force, on the mechanical properties of the amnioserosa and how they change over the course of dorsal closure, on the influence of neighbours and the generation of tissue tension along the anterior-posterior and medio-lateral embryonic axes.

Contact : jocelyn.etienne@ujf-grenoble.fr

Discipline évènement : (Physique)
Entité organisatrice : (LIPhy)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire Mat. Molle/grise)
Site de l'évènement : Polygone scientifique

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