Figure 2

Distinct toxicogenomic expression profiles are induced by different toxicants. (a) Principal component analysis of the toxicogenomic profiles derived from three different embryonic stages. Embryos were exposed to vehicle controls or to one of six chemicals for the periods 4-24 hpf (green), 24-48 hpf (blue), or 96-120 hpf (red). Circles, TCDD: 150 ng/l (24 hpf), 500 ng/l (48 hpf), 500 ng/l (120 hpf). Squares, MeHg: 50 μg/l (24 hpf), 60 μg/l (48 hpf), 60 μg/l (120 hpf). Triangles, VA: 15 mg/l (24 hpf), 50 mg/l (48 hpf), 50 mg/l (120 hpf). Crosses, 4CA: 15 mg/l (24 hpf), 50 mg/l (48 hpf), 50 mg/l (120 hpf). Asterisks, Cd 500 μg/l (24 hpf), 5 mg/l (48 hpf), 5 mg/l (120 hpf). Stars, DDT: 5 mg/l (24 hpf), 15 mg/l (48 hpf), 15 mg/l (120 hpf). While the transcriptional profiles of the 4-24 hpf treatment group (green symbols) cluster closely, characteristic gene-expression profiles were induced by the 24-48 hpf (blue symbols) and the 96-120 hpf (red symbols) exposures to each of the different toxicants. (b) Venn diagram comparing the number of genes induced at the three stages by all six toxicants. Numbers indicate numbers of regulated or co-regulated genes at the different stages (more than 1.95-fold change and adjusted p_adj < 0.025).