Induction of premature chromosome condensation in CHO cells fused with polyethylene glycol

Premature chromosome condensation (PCC) was induced in either suspension or monolayer cultures of Chinese hamster ovary (CHO) cells using the chemical fusogen polyethylene glycol (PEG) or PEG with dimethyl sulfoxide (DMSO). For metaphase-interphase fusions in suspension, the incidence of PCC was comparable to that obtained with UV-inactivated Sendai virus fusion. For monolayer fusions, the incidence of PCC increased gradually after a short exposure to PEG or PEG + DMSO to a maximum at about 10–14 h. Hence, both metaphase-interphase fusions and mitotic asynchrony in multinucleated cells were responsible for the induction of PCC. These results illustrated that no viral components were required for PCC formation.