Polarity determination

We study how molecular motors and cytoskeletal components polarize the largest cell of the animal, the oocyte, using the model organism, Drosophila melanogaster. The primary goal of our research is to decipher the molecular mechanisms underlying the synchronized cytoplasmic movement (ooplasmic streaming), posterior determination and oocyte transport/growth. We combine classic genetics and optogenetics with live imaging to study these processes in details. We have demonstrated that kinesin-driven microtubule sliding powers the ooplasmic streaming (Lu, Winding, et al., PNAS, 2016), which cooperates with cargo transport for posterior determination (Lu et al., JCB 2018). More recently, we show that competition between two motors, kinesin-1 and myosin-V, is essential for the initial posterior determination (Lu et al, BioRxiv, 2019). Currently, we are working to understand how the cargoes are transported from the interconnected nurse cells to the oocyte and how this contributes to the oocyte growth.

During late oogenesis, Drosophila oocyte cytoplasm undergoes circular movement called ooplasmic streaming. Posterior determinants containing the fluorescently labeled marker Staufen move with the cytoplasmic flow, but dramatically slow down near the posterior pole in a wild-type oocyte (right) but not in an oocyte expressing a dominant-negative form of myosin V (left). Spectrum-colored tracks represent the movement of Staufen-containing particles within a 10-min period of time.

Microtubules are connecting the nurse cells with the oocyte through the actin-rich channels (ring canals). Microtubules are labeled the GFP-tagged Patronin and F-actin is stained with Rhodamine-conjugated Phalloidin.

Stable immotile microtubules are closely associated with cortical actin in a streaming oocyte. Microtubules are labeled with the K560Rigor-SunTag system (MT-SunTag) and F-actin is stained with Rhodamine-conjugated phalloidin.

During late oogenesis, Drosophila oocyte cytoplasm undergoes circular movement called ooplasmic streaming. Posterior determinants containing the fluorescently labeled marker Staufen move with the cytoplasmic flow, but dramatically slow down near the posterior pole in a wild-type oocyte (left), but not in an oocyte expressing a dominant-negative form of myosin V (right) . Scale bar, 50 µm.

EB1-GFP comets in the nurse cell (left) and in the oocyte (right)

Microtubule, actin and DAPI staining in a Drosophila egg chamber

Mitochondria movement from the nurse cells to the oocyte

Shot at the gate: How do Drosophila oocytes grow? / Curr. Biol., June 4, 2021 (Vol. 31, Issue 15)

Dynein cargo transport

Dynein glides microtubules and drives cytoplasmic flow.gif

Movement of microtubules and mitochondria

MT gliding by dynein

Shot at the gate: How do Drosophila oocytes grow? / Curr. Biol., June 4, 2021 (Vol. 31, Issue 15)

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