Centrifugal displacement of nuclei in epidermal cells of azuki bean epicotyls

We examined the effects of hypergravity on nuclear positioning in epidermal cells of azuki bean (Vigna angularis) epicotyls. The nucleus was positioned almost in the center of the cell under 1 G conditions. When the epicotyls were exposed to basipetal hypergravity by centrifugation, the nucleus was displaced toward the centrifugal side of the cell in a linear dose-response manner. The nuclear displacement started within 20 min by exposure to basipetal hypergravity at 300 G, and reached ca. 35% from the centrifugal edge of the cell after 2 h. The displaced nucleus recentered by removal of hypergravity stimuli. The nucleus was also displaced by acropetal hypergravity at the similar degree as basipetal hypergravity. The displacement by hypergravity of the nucleus was stimulated, when actin filaments were disrupted by cytochalasin D treatment. These results suggest that the positioning of the nucleus in epidermal cells is maintained by actin filaments, which is affected by gravity in azuki bean epicotyls. ©2019 Jpn. Soc. Biol. Sci. Space; doi: 10.2187/bss.33.1

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