Uptake of the restriction endonuclease AluI by Chinese hamster ovary cells measured by frequencies of induced chromosomal aberrations: effect of hypertonic concentrations of glycerol and sorbitol.

Chinese hamster ovary cells were exposed to the restriction endonuclease AluI in the presence of 2.2 M glycerol or 0.9 M sorbitol using different treatment regimens. Induced chromosomal aberrations were taken as indication for cellular uptake of AluI. The results indicate that cellular uptake of AluI is mediated by vesicles formed during transition of hypertonic to isotonic conditions. Addition of medium leads to breakdown of these vesicles and to liberation of AluI molecules which eventually may reach the chromatin.