Gene expression profiling in zebrafish embryos exposed to 3,4-dichloroaniline (3,4-DCA)

The zebrafish (Danio rerio) embryo toxicity test (DarT) is considered as an alternative to the acute fish toxicity test. However, DarT rarely reveals information on the mechanisms underlying a toxic effect and is relatively insensitive compared to chronic toxic effects. We hypothesized that, by using gene expression profiles as an additional endpoint, it may be possible to increase the sensitivity and predictive value of DarT. Therefore we exposed zebrafish embryos for 48 h to the reference compound 3,4-dichloroaniline and analyzed gene expression patterns with a 14 k oligonucleotide array. Keywords: differential gene expression upon chemical exposure in zebrafish embryos In three independent embryo toxicity tests zebrafish embryos were either treated with the LOEC of 3,4-DCA (12.4 µM) or exposed to test medium (control samples) for 48 hours. Total RNA was extracted and reverse transcribed into aminoallyl-labeled cDNA. Samples of control and treated embryos of all three tests were labeled to Cy3 or Cy5, respectively. For every single experiment dye-swaps were performed, giving a total number of 6 hybridizations.