Generation and application of a novel transgenic zebrafish line Tg(cyp1a:mCherry) as an in vivo assay to sensitively monitor PAHs and TCDD in the environment

The polycyclic aromatic hydrocarbons (PAHs) and 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) are classified as human carcinogens, and can also cause serious health problems. To develop a convenient bio-monitoring tool for the detection of PAHs and TCDD in the environment, we generated a transgenic zebrafish line Tg(cyp1a:mCherry) with cyp1a promoter driving mCherry expression. Here, Tg(cyp1a:mCherry) embryos were treated with different concentrations of TCDD and five US EPA priority PAHs congeners. The results showed that the expressions of mCherry and endogenous cyp1a were consistent with the PAHs exposure concentrations and were largely induced by TCDD and ≥4-ring PAHs. Moreover, the sensitivity of Tg(cyp1a:mCherry) embryos was also evaluated through monitoring of the PAHs contamination in the water and soil samples. The elevated red fluorescent signals and cyp1a expression levels were observed in Tg(cyp1a:mCherry) zebrafish after exposure to water samples and soil organic extracts with higher concentrations of ≥4-ring PAHs. These results further strengthen our findings of concentration- and congener-dependent response of the newly established zebrafish. Taken together, the newly established zebrafish line will prove as a sensitive, efficient and convenient tool for monitoring PAHs and TCDD contamination in the environment.