Transgenic cell lines and changes in gene function and expression: Useful tools in toxicity testing?
Molecular biology provides the toxicologist with powerful tools that can be used in the development and use of in vitro techniques in toxicity testing. As an example, a number of cDNAs coding for human cytochrome P-450 enzymes have been cloned, incorporated in eukaryotic expression vectors and introduced in cell lines. These cell lines can be used to study cytochrome P-450-mediated promutagen activation. To this end, a shuttle vector carrying a bacterial gene, for example beta-galactosidase (lacZ), as a reporter gene for mutations, is introduced in the cytochrome P-450 expressing cell lines. After exposure to putative mutagenic compounds, the shuttle vector is rescued and screened for mutations in bacteria. This system proves to be sensitive and versatile and can be applied to a vast array of cell lines. Another application of molecular biology is the construction of detector cells. Responsive elements are cloned into chloramphenicol acetyltransferase expression vectors or into firefly luciferase expression vectors and introduced in cell lines. These cells can be used in mechanistic studies towards the gene-regulating properties of, for example, dioxins, but also as reporter cells for determination of dioxin contamination.
Horbach
G J
GJ
Research Institute of Toxicology, Utrecht University, PO Box 80.176, NL-3508 TD Utrecht, The Netherlands.
De Groene
E M
EM