Figure 2.
ahr2-dependence of wfikkn1 developmental expression. wfikkn1 expression in 48 h postfertilization (hpf) (A) and 120 hpf (B) wild-type 5D (WT) and ahr2-null (ahr2osu1) whole embryos developmentally exposed to 0.1% dimethyl sulfoxide or 1 ng/ml 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; n = 3–4 reps/treatment). wfikkn1 expression was significantly increased upon exposure to TCDD only in WT zebrafish, and there was no significant increase in ahr2-null zebrafish at both timepoints. Expression values were analyzed using the 2−ΔΔT method, and β-actin was used as the normalization control. Different letters indicate statistical difference (p < .001, Type I 2-way ANOVA with a post hoc Tukey test). C, Schematic diagram of the wfikkn1 gene locus (not to scale) on the reverse strand of Chromosome 1 of the zebrafish genome. Zebrafish have 2 predicted wfikkn1 transcripts (TSS, transcription start site). The 6 identified aryl hydrocarbon response element consensus sequences, “GCGTC” (Chang et al., 2013; Karchner et al., 2002) in the 5-kb region upstream of the TSS are highlighted in the top panel. The bottom panel shows the top 10 predicted transcription factor binding sites from Genomatix (Cartharius et al., 2005). Abbreviations: NEUR, NeuroD; Beta2, HLH domain; BRAC, Brachyury gene, mesoderm developmental factor; NKXH, NKX homeodomain factors; FKHD, fork head domain factors; TAIP, TGF-β-induced apoptosis proteins).