Description du projet
Des activités microscopiques de la chromatine aux propriétés macroscopiques qui en découlent
La quantité colossale d’ADN contenue dans une cellule est enroulée autour de protéines comme des perles sur un fil dans un complexe appelé chromatine. De plus en plus de données probantes suggèrent que les propriétés matérielles émergentes de la chromatine régulent des processus nucléaires essentiels. La caractérisation de ces propriétés s’est avérée délicate, car les études in vitro ne tiennent pas compte de la complexité de la machinerie cellulaire et les études sur les cellules intactes ne permettent pas d’accéder facilement à la dynamique à petite échelle. Le projet SynthNuc, financé par l’UE, comblera le fossé des échelles grâce à des extraits d’œufs de Xenopus laevis et à des noyaux synthétiques constitués de séquences d’ADN préétablies. Des techniques expérimentales de haute technologie permettront de comprendre comment les activités collectives à petite échelle de la chromatine donnent naissance à ses propriétés matérielles à grande échelle.
Objectif
The main aim of this proposal is to resolve how the physics of molecular-scale activities result in the emergent material properties of chromatin and how those contribute to chromatin organization and function. Mounting evidence suggests that the material properties of chromatin regulate essential nuclear processes. Chromatin has been studied with two disconnected approaches; pure in vitro studies, perfectly suited for careful biophysical measurements on single DNA molecules but lacking the complexity of a cell, or intact cell measurements, with limited access to measure material properties and small-scale chromatin dynamics. The physical properties of chromatin, however, are emergent and result from the molecular activities that are in turn regulated by those properties. As a consequence, it is crucial to establish new experimental assays that connect these two scales and levels of complexity. Here, I will bridge the gap in scales and biochemistry between pure in vitro assays and measurements in intact cells by reconstituting chromatin processes in Xenopus laevis egg extracts across scales. I will combine quantitative microscopy, optical tweezer measurements, and theory to biophysically characterize the self-organization of protein-DNA co-condensation and loop extrusion and single chromatin molecules of increasing complexity. To bridge the microscopic and the macroscopic scales, I will assemble synthetic nuclei made of pre-engineered DNA sequences, which allows for exquisite control of DNA length, amount, and chromatin activities. In combination with microrheology, micropipette aspiration, and magnetic tweezers, I will unravel how the collective behavior of chromatin activities gives rise to the emergence of large-scale material properties of chromatin. This project will provide a physical description of the material state of chromatin across scales and contribute to reveal the basic physical principles that govern nuclear organization and function.
Champ scientifique
Mots‑clés
Programme(s)
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Régime de financement
HORIZON-ERC - HORIZON ERC GrantsInstitution d’accueil
01069 Dresden
Allemagne