Mitosis of rotenone-induced endoreduplication in Chinese hamster cells.

Endoreduplication was induced by rotenone with an extremely high frequency (approximately 90% of all the metaphases) in cultured Chinese hamster cells. Endoreduplicated cells were fixed without colchicine or hypotonic treatment, and chromosomal configurations were examined in various mitotic stages. The two sister chromosomes of each diplochromosome at late prophase were widely separated except the centromeric region, but they became gradually paired along the total length as the cell cycle progressed to metaphase. The anaphase cells underwent multipolar division, resulting in three or four aneuploid daughter cells. Indirect immunofluorescence staining using anti-beta tubulin antibody revealed tripolar or tetrapolar spindles and unusual equatorial plates.