Fig. 2.

TCDD reduces sox9b expression in the zebrafish larval heart. Zebrafish embryos carrying the sox9b:EGFP reporter were exposed to TCDD as described in Materials and Methods. Embryos were examined at 72 hpf using confocal microscopy and representative lateral images are shown: (A) control heart, (B) TCDD-treated. White outline denotes ventricle (V); anterior is to the left. (C) Hearts were isolated at 72 hpf for quantitative reverse-transcription polymerase chain reaction measurement of sox9b expression, normalized to β-actin mRNA for each treatment group. Results are mean ± S.E., n = 3 replicate experiments. Asterisk denotes significantly different from controls (P < 0.05).