Mouse germline cysts contain a fusome-like structure that mediates oocyte development (opens in new tab)

Mouse female primordial germ cells (PGCs) undergo five synchronous, incomplete mitotic divisions and send each resulting germline cyst into meiosis to fragment and produce 4–6 oocytes and 24–26 supportive nurse cells. However, no system of polarity has been found to specify mammalian oocytes, link them appropriately to nurse cells and enable them to acquire high-quality organelles and cytoplasm. We report that mouse cysts develop an asymmetric Golgi, endoplasmic reticulum (ER), and microtubul...