![]() At division, stem cells generate two cells with distinct fates: (1) a cell that is an exact copy of its precursor, maintaining the “stemness,” and (2) a daughter cell that will subsequently differentiate ( Betschinger and Knoblich, 2004 Inaba and Yamashita, 2012). Stem cells are fundamental for the generation of all tissues during embryogenesis and replace lost or damaged cells throughout the life of an organism. Our work shows that centromere assembly epigenetically drives GSC maintenance and occurs before oocyte meiosis. Finally, continued CENP-A assembly in differentiated cells is nonessential for egg development. Importantly, symmetric incorporation of CENP-A on sister chromatids via HASPIN knockdown or overexpression of CENP-A, either alone or together with its assembly factor CAL1, drives stem cell self-renewal. Furthermore, chromosomes inherited by GSCs incorporate more CENP-A, making stronger kinetochores that capture more spindle microtubules and bias segregation. Specifically, CENP-A deposition is promoted by CYCLIN A, while excessive CENP-A deposition is prevented by CYCLIN B, through the HASPIN kinase. We show that Drosophila female germline stem cells (GSCs) and neuroblasts assemble centromeres after replication and before segregation. Previous studies suggest asymmetric inheritance of centromeric proteins upon stem cell division however, the mechanism and implications of selective chromosome segregation remain unexplored. Centromeres are epigenetically defined by CENP-A–containing chromatin and are essential for cell division.
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