Transgenic zebrafish for detecting mutations caused by compounds in aquatic environments.

We have established a transgenic zebrafish line carrying a shuttle vector plasmid (pML4) for detecting mutagens in aquatic environments. The plasmid contains the rpsL gene of Escherichia coli as a mutational target gene, and the kanamycin-resistance gene for recovering the plasmid from the chromosomal DNA. To evaluate the system, we treated embryos of the transgenic fish with N-ethyl-N-nitrosourea (ENU), which induces a dose-dependent increase in the mutation frequency of the target gene. The mutation spectrum was consistent with the proposed mechanism of ENU mutagenesis. Similarly, treating the embryos with benzo[a]pyrene or 2-amino-3, 8-dimethylimidazo[4,5- f]quinoxaline, which are found in naturally polluted water, significantly increased the frequency of mutations in the target gene.