Induction of chromosomal aberrations with the restriction endonuclease AluI in Chinese hamster ovary cells: comparison of different treatment methods.

Chinese hamster ovary (CHO) cells were treated with the restriction endonuclease AluI using various methods; namely, treatment in the presence of hypertonic concentrations of glycerol or sorbitol and electroporation. The frequencies of chromosomal aberrations induced were scored in first post-treatment metaphases. For all treatment schedules linear dose-effect relationships of polycentric chromosomes were found. The distribution of polycentric chromosomes induced by AluI was overdispersed. Inhibition of cellular energy metabolism with sodium azide and 2-deoxyglucose led to a strong reduction of the frequencies of chromosomal aberrations when the treatment with AluI was carried out in the presence of glycerol or sorbitol, but not when carried out by electroporation. This is interpreted to mean that glycerol- or sorbitol-mediated cellular uptake of AluI, but not the uptake via electroporation, is an energy-dependent mechanism.