MP7 Toxicogenomics in Environmental Studies
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(KLA-1117-802859) Gene expression in Pimephales and Daphnia spp. after pharmaceutical exposures: links to behavior, survival, reproduction.

Klaper, R¹, Rees, C¹, ¹ University of Wisconsin Milwaukee

ABSTRACT- Gene expression studies provide a mechanism to examine the functional response of an organism to environmental changes. Through the use of suppressive subtraction libraries, micro- and macro-arrays, differential display, and quantitative PCR, many biomarkers become available to decipher the response of an organism to toxins. Using Pimephales promelas and Daphnia spp. as models, the effects of pharmaceutical (naproxen, clofibrinic acid, and fluoxetene) and methyl mercury exposures were investigated using gene expression. Results demonstrate the potential for genomic markers to be used as an early indicator of physiological response to different chemicals. In addition, gene expression provides an indication of the effects of these chemicals. Pharmaceutical exposure resulted in altered expression of genes associated with chemical specific pathways. Methyl mercury exposure in fatheads results in a decline in reproduction and changes in gene expression associated with reproduction. Mercury reduces vitellogenin expression in female fatheads and increases vitellogenin in male fatheads, but it is a highly variable response. This variation was confirmed using both quantitative PCR and macroarray. Our studies examine the variation in gene expression, sex, and genotype among individuals exposed to the same environment. We have found sex contributes strongly to gene expression response not only in genes associated with reproduction but other functions as well. We have begun to examine the ability to detect differences in gene expression response in the field in naturally occurring populations of fish to determine the capability of using this technique as an early warning of problems due to contaminants.

Key words: toxicogenomics, pharmaceuticals