Lu Wen, Lakonishok Margot, Serpinskaya Anna S, Gelfand Vladimir I
Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, United States.
Elife. 2022 Feb 16;11:e75538. doi: 10.7554/eLife.75538.
Cytoplasmic dynein, a major minus-end directed microtubule motor, plays essential roles in eukaryotic cells. oocyte growth is mainly dependent on the contribution of cytoplasmic contents from the interconnected sister cells, nurse cells. We have previously shown that cytoplasmic dynein is required for oocyte growth and assumed that it simply transports cargoes along microtubule tracks from nurse cells to the oocyte. Here, we report that instead of transporting individual cargoes along stationary microtubules into the oocyte, cortical dynein actively moves microtubules within nurse cells and from nurse cells to the oocyte via the cytoplasmic bridges, the ring canals. This robust microtubule movement is sufficient to drag even inert cytoplasmic particles through the ring canals to the oocyte. Furthermore, replacing dynein with a minus-end directed plant kinesin linked to the actin cortex is sufficient for transporting organelles and cytoplasm to the oocyte and driving its growth. These experiments show that cortical dynein performs bulk cytoplasmic transport by gliding microtubules along the cell cortex and through the ring canals to the oocyte. We propose that the dynein-driven microtubule flow could serve as a novel mode of fast cytoplasmic transport.
胞质动力蛋白是一种主要向微管负端移动的马达蛋白，在真核细胞中发挥着重要作用。卵母细胞的生长主要依赖于与其相连的姐妹细胞（滋养细胞）细胞质成分的贡献。我们之前已经表明，胞质动力蛋白是卵母细胞生长所必需的，并假设它只是沿着微管轨道将货物从滋养细胞运输到卵母细胞。在这里，我们报告，皮质动力蛋白不是沿着固定的微管将单个货物运输到卵母细胞中，而是在滋养细胞内以及通过细胞质桥（环管）从滋养细胞到卵母细胞主动移动微管。这种强大的微管运动足以将即使是惰性的细胞质颗粒通过环管拖到卵母细胞中。此外，用与肌动蛋白皮质相连的向微管负端移动的植物驱动蛋白取代动力蛋白，足以将细胞器和细胞质运输到卵母细胞并驱动其生长。这些实验表明，皮质动力蛋白通过沿着细胞皮质滑动微管并通过环管将微管运输到卵母细胞来进行大量细胞质运输。我们提出，动力蛋白驱动的微管流动可以作为一种新型的快速细胞质运输模式。
