Gene Expression Profile Assessment in Zebrafish (Danio rerio)

The Zebrafish Danio rerio, in the last decade, has been recognized as the best model among the vertebrate model organisms. The exquisite features and the high homology with the mammalian system have facilitated its application in many field e.g. eco-toxicology, biomedicine, genetics and physiology. The complete sequencing of the genome provided enormous value giving the possibility to develop a DNA microarray for gene expression analysis. Gene expression represents a unique way of characterizing how cells and organisms adapt to changes in the external environment (Lettieri, EHP, 2006). The measurements of gene expression levels, upon exposure to a chemical, can be used both to provide information about the mechanism of action of the toxicant, and also to form a sort of �genetic signature� for the identification of toxic products. Benzo[a]pyrene (BaP) is a well-known chemical pollutant, which belongs to the family of polycyclic aromatic hydrocarbons (PAHs) which are formed during combustion processes. Extensive studies have been published on the metabolism and the toxicity of PAHs, as well as epidemiologic studies which suggest a role of the PAHs in carcinogenetic and mutagenic effects in many species. BaP as well as other PAHs is included in the Priority Hazardous Substances adopted in November 2001 by the new Water Framework Directive (2000). Our studies focused on the analysis of gene expression changes in a liver cell line of Zebrafish upon exposure to BaP concentrations close to environmental level using DNA Microarrays. In our gene expression analysis, we identified nine genes, among them the cyctochrome P450 CYP1A involved in the xenobiotic response and the cyb5 whose role in the activation of human CYP1A2 was recently reported in the literature.

JRC.H.5 - Rural, water and ecosystem resources