Induction of Cyp1a by TCDD is inhibited in dnAhr2^1–440-transgenic zebrafish.

Transgenic and wild type AB fish were exposed to TCDD or vehicle and ethoxysresorufin was added as described in Materials and Methods. Representative images showing the fluorescent product of Cyp1a metabolism are shown for wild type AB and dnAhr2^1–440 transgenic fish.

dnAhr2^1–440 -transgenic zebrafish are resistant to pericardial edema caused by TCDD.

Transgenic and wild type AB zebrafish were exposed to TCDD immediately following fertilization, and the severity of pericardial edema was scored for each fish at 96 hpf. For each type of fish, the bars indicate the distribution across each of the 4 possible categories of severity: Dark bars indicate dnAhr2^1–440-transgenics; light bars indicate wild type. Representative photographs illustrate each severity score. Asterisk indicates a significant difference between the transgenic and wild type percentage for that severity category, p<0.05.