PARENT SESSION

PH14 Ecotoxicogenomics
Exhibit Hall
8:00 AM - Thursday

(PH168) Use of rainbow trout oligonucleotide microarray to examine differential gene expression of known toxicants.

Tilton, S¹, Williams, D¹, ¹ Marine and Freshwater Biomedical Sciences Center, Oregon State University, Corvallis, OR, USA

ABSTRACT- Microarrays allow for identification of functionally significant genes and pathways involved in biological responses important for disease. Analysis of gene expression patterns in response to known toxicants using non-mammalian organisms, such as rainbow trout (Oncorhynchus mykiss), not only provides mechanistic information for risk assessment, but also helps to identify potentially conserved mechanisms of action across species. Rainbow trout has served as a sensitive aquatic model for studies of environmental toxicology, carcinogenesis, endocrinology, comparative immunology and stress physiology. In this study, we have utilized a custom rainbow trout 70-mer oligonucleotide array containing 1500 genes known to be important for the physiological processes described above. Juvenile fish were exposed to several toxicants, including 17-estradiol and -naphthoflavone, and total hepatic RNA was isolated and hybridized to arrays for analysis of differential gene expression. Genes found to be regulated by toxicant exposure, such as those important for estrogen receptor and aryl hydrocarbon receptor mediated responses, were confirmed by both western blot and real time RT-PCR. For example, estradiol differentially regulated many genes in trout liver including upregulation of genes important for cellular growth and vitellogenesis and downregulation of genes involved in the acute immune response. Overall, this research will help to identify genes important for toxicant action in the rainbow trout model. Supported by NIH grant ES03850 and ES07060.

Key words: gene expression, microarray, rainbow trout, estrogen