Live characterization of Drosophila melanogaster female germline stem cells

Abstract

The germline stem cells (GSCs) present in the Drosophila melanogaster adult ovary have long been used as a suitable model to study stem cell (SC) behaviour inside its natural microenvironment or niche. GSCs generally divide asymmetrically, as they give rise to one daughter SC that remains in the niche and to a sister cell that enters oogenesis and differentiates into the oocyte and the nurse cell cluster. A large body of research using the fly ovary has allowed the deciphering of different processes that take place in the niche such as cell fate determination, division orientation, intercellular communication, etc. However, because of the long duration of a GSC’s cell cycle (around 20 hours), some descriptions were limited by the difficulties of performing long-term ex vivo analysis of these processes. We have used a combination of genetic tools (such as FlyFUCCI and a myriad of fluorescent proteins) and an ex vivo culture protocol that permits filming live GSCs for long periods of time (at least 10 hours) to describe in detail several processes that occur during GSC proliferation. We will present our recent results that define the behaviour of the spectrosome - the membranous organelle that is essential for proper orientation and division of the GSCs – and its growth throughout the cell cycle, the correlation of cell cycle progression with changes in spectrosome morphology and the behaviour of centrosomes during GSC proliferation.