Effects of methylmercury on genome-wide gene expression in the liver of Atlantic cod (Gadus morhua)

Methylmercury (MeHg) is a highly toxic environmental pollutant. To understand the mechanisms of toxicity of the compound and possibly to discover new biomarkers for environmental monitoring, we have conducted toxicogenomics studies. We designed 126k-cod-oligonucleotide arrays and performed genome-wide gene expression assays in liver samples from juvenile cod treated with MeHg (0.5 and 2 mg/kg body weight). Microarray analysis showed MeHg differentially regulated hundreds of genes. Gene Ontology and pathway analyses of differentially regulated genes revealed that MeHg modulated mainly genes involved in immune response, oxidative stress response, tissue remodelling, and energy pathways such as lipid, carbohydrate and amino acid metabolism. The results provide insights into the mechanisms of toxicity of MeHg and provide candidate biomarkers of exposure to MeHg for further evaluation. Analyzed 5 samples from each of 3 groups: control, 0.5 mg/BW MeHg treated, and 2 mg/BW MeHg treated. Liver total RNA was reverse transcribed, Cy3-labeled, and hybridized (one-color hybridzation).