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Accueil du site > Séminaires > Archives séminaires > Séminaires 2016 > Séminaire MSC. 12 décembre 2016. Sigolène Meilhac (Institut Pasteur) :"Morphogenesis of the heart : looping and ballooning of a tube".

Séminaire MSC. 12 décembre 2016. Sigolène Meilhac (Institut Pasteur) :"Morphogenesis of the heart : looping and ballooning of a tube"

Sauf mention contraire, les séminaires et les soutenances se déroulent à 11h30 en salle 454A du bâtiment Condorcet.


Morphogenesis of the heart : looping and ballooning of a tube

Sigolène Meilhac, Institut Pasteur

The heart provides a striking model of morphogenesis in 3D, in which the shape and alignment of cardiac chambers are crucial for the function of driving blood circulation. The primordium of the heart is a tube, which acquires a helical shape during the process of looping. Cardiac chambers balloon out from the tube. We aim to understand how coordination of cell behaviour is involved in these morphogenetic processes in the mouse embryo. By clonal analysis, we have shown that growth of the cardiac muscle is oriented. As orientations are specific to different cardiac regions, it suggests that oriented growth may be important for the fine and specific shaping of cardiac chambers. Previously, anisotropies underlying organ morphogenesis have been quantified as a 2D problem, taking advantage of a reference axis. However, this is not applicable to the heart, in which the looped geometry cannot be easily transposed in 2D. To assess which is the cell behaviour underlying oriented growth of the myocardium, we have developed a procedure to quantify cell orientations in a 3D tissue. With this, we have shown that cell division is oriented in the embryonic heart, such that it underlies cardiac chamber expansion but not transmural thickening. Looping of the tube is an asymmetric event, corresponding to the first morphological sign of left-right asymmetry in the mouse embryo. Establishment of molecular left-right patterning of the embryo has been well studied and relies on a left-right organiser. However, how heart precursors receive left-right signals and how asymmetric cell behaviour promotes the looping of the heart tube has remained poorly understood. Based on computer simulations and quantifications in 3D of the tube geometry, we propose a novel buckling model of heart looping. The model can predict mutant phenotypes that can be tested experimentally. Our work provides novel insight into the mechanisms of mouse heart morphogenesis and provides tools for the analysis of morphogenesis in 3D.


Contact : Équipe séminaires / Seminar team - Published on / Publié le 23 novembre 2016


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