Figure 4.

RT-PCR analysis confirms selected gene responses. Embryos were exposed to the indicated toxicants (500 ng/l TCDD; 15 mg/l DTT; 5 mg/l Cd; 60 μg/l MeHg; 50 mg/l VA; 50 mg/l 4CA; 79 mg/l As) or vehicle alone (embryo medium or 0.2% ethanol or 0.025% DMSO, 1.4 mg/l toluene) between 96 and 120 hpf. (a) cDNA was synthesized and subjected to PCR with primers specific for the selected genes indicated. Gene ID refers to the accession number in GenBank. The number of temperature cycles (cycle numbers) for every set of amplifications is indicated. The fold-change column summarizes the results from the microarray experiments for comparison with the RT-PCR results shown in (b). See legend of Figure 1 for details of treatments and controls. β-actin mRNA was used as a toxicant-insensitive reference. ND, not determined, as the actin gene response fell into the class of nonregulated genes in the microarray results.