Fig. 4. Dynein does not localize to the female pronucleus in the absence of a sperm aster. Parthenogenetic activation of bovine oocytes induces female (F) pronuclear formation and microtubule polymerization without aster formation. Dynactin p150^Glued (green; left) concentrates around the female pronucleus (blue), whereas dynein intermediate chain (green; right) distributes near the cortex, enriched with unfocused microtubules (red). Dynein is not detected at the female pronuclear surface. The arrow shows dynactin surrounding the female pronucleus. Scale bar, 10 µm.