Significant differences in the structural basis of the induction of sister chromatid exchanges and chromosomal aberrations in Chinese hamster ovary cells.

The structural basis of the induction of sister chromatid exchanges (SCE) and chromosomal aberrations (Cvt) in Chinese hamster ovary cells was investigated by the CASE (Computer Automated Structure Evaluation) method, an artificial-intelligence-based system. Using the relevant National Toxicology Program data bases CASE identified a set of structural determinants responsible for the induction of SCE and another one for Cvt. A comparison between the structural determinants associated with SCE and Cvt revealed an overlap of only 22.6%, while the overlap between SCE and the determinants of mutagenicity in Salmonella is 54.5%. This indicates a) that the structural bases of the two phenomena differ and b) that it is likely that SCE, but not Cvt, involves a significant electrophilic/DNA-damaging component.