Fusion of L line daughter cells in the presence of Sendai virus.

Sendai virus induces the fusion of daughter cells in a population of murine fibroblasts (L cell line). Mitosis and the ensuing fusion of two daughter cells has been observed by means of time-lapse cinemicrography. The paper documents two types of cell fusion: a) two daughter cells become completely separated at the end of the mitosis, and fuse only after a certain period of time, or b) the daughter cells remain attached through a narrow bridge of cytoplasm which persists between the cells as a consequence of incomplete cytokinesis. Widening of the cytoplasmic bridge ultimately results in the fusion of cells. The interval between the termination of mitosis and the fusion ranged from 45 to 60 min. The biological significance of the resulting polyploid cells is discussed.