EASTBIO Dissecting centromere identity and epigenetic inheritance

The centromere is a specialized chromatin region that is essential for proper segregation of mitotic chromosomes by forming a kinetochore. Centromere dysfunction results in aneuploidy or loss of chromosomes and is associated with cancer and miscarriage. In most eukaryotes centromeres are not encoded by DNA, but instead epigenetically defined by the histone H3-variant CENP-AcenH3 (dCENP-A/CID in flies). The molecular mechanisms by which CENP-A is deposited and how centromere identity is propagated through many cell divisions is still poorly understood. The simplicity of the Drosophila centromere makes it an ideal model to study CENP-A inheritance. In this project, we propose to reconstitute the dCENP-A deposition machinery (CAL1 and dCENP-C) bound to centromeric dCENP-A nucleosomes in vitro using recombinant proteins from E.Coli and baculovirus. Further insight into the structure of the dCENP-A machinery will be gained using X-ray crystallography and cryo electron microscopy in collaboration with the Jeyaprakash lab. The results obtained during this Ph.D. project will help understanding the molecular underpinnings of epigenetic propagation of centromere identity.