MICRONUCLEI AS A BIOLOGICAL END-POINT FOR GENOTOXICITY - A MINIREVIEW

The in vitro micronucleus assay has now been applied in many laborator ies. This endpoint is useful in biomonitoring or ecotoxicology, as a s ensitivity measure of human cells in cancer treatment and also to repl ace or supplement other in vitro genotoxicity assays. Learning more ab out the mechanisms of micronucleus formation allows conclusions about its biological significance. It has been demonstrated that disturbance of the mitotic apparatus (spindle, kinetochores) as well as impaired function of topoisomerase II can be involved in micronucleus formation . In addition, the roles of changes in DNA-conformation that are induc ed by alterations in the status of cytosine-methylation and of the cel lular DNA repair capacity have been shown. The fate of micronucleus-co ntaining cells is not known: the cells may theoretically be cytostatic and micronucleus-formation may therefore be a way of the organism to eliminate genetic damage or the cells may survive the loss of that chr omosomal material and develop into transformed cells. Published data a nd ideas of selected areas within this field are reviewed. (C) 1997 Pu blished by Elsevier Science Ltd.