Figure 4

Ethanol induces asymmetric division of neural progenitor cells. Dissociated neural progenitor cells (A) cultured under mitogenic conditions divide symmetrically to generate two similar daughter cells (D, representative examples of cells undergoing cytokinesis), and regenerate new neurospheres (data not shown). Ethanol (120 mg/dl)-treated neural progenitors also generate daughter cells by symmetrical division (B, examples of cells in different stages of cytokinesis), to regenerate neurospheres over a period of 44 (E) and 72 (G) hours, under mitogenic conditions. However, despite being cultured under mitogenic conditions, ethanol-treated progenitors also exhibit asymmetric division to generate morphologically dissimilar daughter cells (C, examples of asymmetrical division, showing daughter cells in different stages of cytokinesis). Over the period of 44 to 72 hours, one daughter cell exhibits somatic mobility (e.g., F,H, cell marked by a *), while the second daughter cells remains stationary (e.g., F,H, cell marked by +). The motile daughter cell transiently exhibits long filamentous processes (F,*), though these processes retract over a period of 72 hours (H,*), in mitogenic medium.