Descripción del proyecto
Información molecular sobre la recombinación cromosómica durante la meiosis
La producción de roturas de doble cadena (DSB, por sus siglas en inglés) de ADN durante meiosis es necesaria para la recombinación y la fertilidad. Sin embargo, la DSB meiótica supone un gran desafío para la integridad genómica. El proyecto financiado con fondos europeos DSBSunrise investigará la hipótesis de que este proceso está estrechamente regulado para garantizar la reparación eficiente de las DSB de ADN mediante recombinación homóloga. Los investigadores proporcionarán información topológica sobre el proceso e identificarán los localizaciones genómicas en las que se produce la DSB. También estudiarán cómo interactúan las localizaciones genómicas de la DSB con los componentes estructurales del mecanismo de reparación, lo que ofrecerá información fundamental sobre el complejo proceso de la recombinación cromosómica meiótica.
Objetivo
At the onset of prophase of the first meiotic division, meiotic cells undergo complex molecular events with the induction of several hundred DNA double-strand breaks. These DNA breaks are required because they initiate recombination between homologous chromosomes and to allow chromosome segregation during meiosis. They are essential for fertility. However, they represent a major challenge for genome integrity.
It is thought that meiotic DNA break formation is under tight control to ensure that all breaks are properly repaired to maintain genome integrity. But how this control implemented is unknown.
We postulate that three critical steps take place to ensure meiotic DNA break formation at the right time, right place, and right frequency. We will test this hypothesis by addressing in mice the three following questions:
Q1: We will ask whether a homology-sensing process brings homologous chromosomes in spatial proximity before DNA break formation to improve DSB repair efficiency and avoid topological conflicts. If this is the case, we will determine the molecular mechanism.
Q2: We will determine whether the genomic sites undergoing DNA breakage interact with structural components of chromosome axes before break formation, and how. This interaction is predicted to be necessary for proper DSB repair.
Q3: We will determine how DNA cleavage is activated. We will do this through in vitro reconstitution of meiotic DSB formation.
Answering these key questions will be possible by using in vivo and in vitro approaches. We will pioneer in vitro meiotic differentiation of mouse embryonic stem cells to overcome the current limitations for identifying novel components and interactions.
We will thus decipher how a molecular machinery that has evolved from a DNA type II topoisomerase family has been selected and modified to promote a complex reaction initiated by DNA cleavage at multiple sites along chromosomes followed by their repair by homologous recombination.
Ámbito científico
Programa(s)
Régimen de financiación
ERC-ADG - Advanced GrantInstitución de acogida
75794 Paris
Francia