Gene-expression profiling in gill and liver of zebrafish exposed to produced water

The effects of produced water (a by-product of oil and gas extraction) oil gene expression were studied in gills and liver tissues of zebrafish. Adult, non-breeding zebrafish were exposed to control (freshwater mixed with 5% seawater) or produced water (freshwater mixed with 5% of produced water from the Oceberg C Oil Platform in the North Sea). A zebrafish library was used to make a microarray that consisted of 15,806 unique genes. The results indicate that 27 genes in the gills and 55 genes in the liver show significantly altered expression (greater than two-fold change). More than 70% of these gene sequences have not been annotated in the Gene Ontology (GO) database, making it difficult to characterize the affected genes. CYP1A displayed the greatest upregulation in the gills (eightfold, verified with quantitative real-time PCR). This study illustrates the utility of microarray approaches in investigations of environmental effects of toxicants.