Lead (Pb)-induced expression of the abcc4 gene in developing embryos and adult tissues of zebrafish. (A) Induced expression of the zebrafish abcc4 gene in developing embryos under lead stress. Embryos were treated with 5 μM lead from 24 to 120 h post-fertilization (hpf) and subjected to whole-mount RNA in situ hybridization (WISH) with antisense RNA probe. (a,b) Lateral views; (c,d) dorsal views. Yellow, white and red dashed lines indicate the oral cavity, gill and pronephric tubules, respectively. (B) Transcriptional responses of the zebrafish abcc4 gene to lead treatments in adult tissues. Adult zebrafish were exposed to various concentrations of lead for 24 h. Gills and intestines were taken from four females, and kidneys were taken from four females and four males. The same tissues from different fish were mixed for isolation of total RNA and subjected to qRT-PCR analysis of abcc4 mRNA levels relative to the control. One-way analysis of variance (ANOVA) followed by Duncan’s post-hoc test was performed, and the symbol above the error bars indicates a significant difference (* p < 0.05 and ** p < 0.01) of mRNA levels in the same tissue among the indicated doses of treatments.