Induction of premature chromosome condensation in Drosophila melanogaster-rat heterokaryons.

After fusion mediated by polyethylene glycol (PEG) plus dimethyl sulfoxide (DMSO) between rat and Drosophila melanogaster cells cultured in vitro, the phenomenon of premature chromosome condensation (PCC) induced by mitotic rat chromosomes was detected in Drosophila nuclei. Exceptionally PCC was induced in rat nuclei but only in the presence of a very high ploidy level of Drosophila mitotic chromosomes. This provides further evidence of the lack of species specificity and of the effect of dosage of the PCC inducing factors, even among very distant species.