Premature chromosome condensation: a mechanism for the elimination of chromosomes in virus-fused cells.

The fate of prematurely condensed chromosomes (PCC) that are induced following fusion between a mitotic and an interphase cell was studied in the homokaryons of HeLa and 2 glycine-requiring mutants of Chinese hamster ovary cells. The data indicate: (1) the prematurely condensed chromosomes are often incorporated into daughter nuclei of the fused cells and hence they are functionally retained by the progeny; (2) in general, the only viable products of fusion between mitotic and interphase cells are those where PCC has been induced; (3) fusion between mitotic and 5-phase cells leads to the most rapid loss of chromosomes, while the homophasic fusions tend to produce more stable hybrids with regard to their chromosome number.