PARENT SESSION

2E - Genomics, Proteonomics, Metabolomics
Poster Hall
8:30 AM - Tuesday, 29 April 2003

(TUP/112) Changes in gene expression in sheepshead minnows (Cyprinodon variegatus) exposed to varying concentrations of estradiol and nonylphenol.

Knoebl, Iris¹, Hemmer, Michael², Denslow, Nancy¹, ¹ University of Florida, Gainesville, FL, U.S.A.² U.S. Environmental Protection Agency, NHERL, Gulf Breeze, FL, U.S.A.

ABSTRACT- Many environmentally persistent chemicals found in both European and U.S. waterways can act as estrogens by binding to estrogen receptors and modifying the expression of genes regulated by endogenous estrogens. Synthesis of female-specific proteins (vitellogenin [VTG], vitelline envelope proteins [ZP]) in male fish is used as an indicator of estrogen exposure. However, protein synthesis can be delayed up to several days after exposure to estrogenic chemicals. An indicator of more immediate changes in gene expression is the measurement of changes in mRNA levels. We have developed microarray technology to assess changes in gene expression in male sheepshead minnows exposed to varying concentrations of 17-estradiol and nonylphenol. We have also developed quantitative real-time PCR assays to measure the hepatic mRNA of two VTGs ( and ) and two ZPs (2 and 3). Using this technology we observed increases in both VTG and in male fish exposed for 6 h to 100 ng/L of 17-estradiol. We exposed male fish to five concentrations of 17-estradiol (50 to 1000 ng/L) for various times (6h to 48 h and 2 d to 22 d). We found dose-response changes in VTG mRNA levels with 10-fold lower concentrations of VTG compared to VTG . We also exposed male fish to concentrations of nonylphenol ranging from 0.64 to 42.7 ug/L for 2 to 56 days. We present the temporal and dose-response comparisons of mRNA induction for two VTGs and two ZPs measured by quantitative real-time PCR. We also present changes in expression of other genes of interest using microarray technology.

Key words: vitellogenin, microarray, vitelline envelope, sheepshead minnow