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Emergence des mouvements morphogénétiques dans la gastrula de poisson zèbre

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Auteur / Autrice : Yara Hassanein
Direction : Nicolas David
Type : Projet de thèse
Discipline(s) : Biologie
Date : Inscription en doctorat le 01/10/2024
Etablissement(s) : Institut polytechnique de Paris
Ecole(s) doctorale(s) : École doctorale de l'Institut polytechnique de Paris
Partenaire(s) de recherche : Laboratoire : LOB - Laboratoire d'Optique et Biosciences

Résumé

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How embryos are built is a fundamental question of developmental biology, with direct applications to regenerative medicine. Decades of research have largely unraveled how cells acquire specific fates. But how these fates translate into specific behaviors leading to large-scale morphogenetic movements remains largely unknown. We believe that one of the difficulties in answering this question is that it may be incorrectly stated, that cell behavior may not be uniquely or entirely controlled by fate. Inspired by active matter physics we propose to identify the key parameters governing the emergence of morphogenetic movements, whether these parameters are intrinsic, defined by cell fate (spontaneous motility, response to contact with neighbors), or extrinsic, defined by cell environment (cell density, geometry of the environment). This will be done on the zebrafish mesendoderm during gastrulation. The mesendoderm is composed of subpopulations of different fates, undergoing different morphogenetic movements. Fates can be genetically controlled, and different techniques (cell transplants, laser ablations, opto-genetics) allow modification of the cell environment, so that the model is ideal to pinpoint which parameters lead to morphogenetic movements. In a bottom-up approach, we will first unravel the molecular bases of cell-cell interactions, which, we recently demonstrated, are key modifiers of cell behaviors. Isolating cells, we will then precisely characterize their autonomous, fate-induced, behaviors. From there, we will progressively complexify their environment, to see how this modifies cell behavior, and identify the key parameters leading to the emergence of large-scale morphogenetic movements.