Meeting Abstract

85.3  Tuesday, Jan. 6 10:45  Perchlorate exposure alters gene expression in primary germ cells and developing gonads of zebrafish and stickleback fishes PETERSEN, A.*; EARP, N.; FITCH, C.; REDMOND, A.; YAN, Y.; BREMILLER, R.; DILLON, D. ; GARDELL, A. ; BUCK, C.L.; VON HIPPEL, F.; POSTLETHWAIT, J.H.; CRESKO, W.A.; University of Oregon; University of Oregon; University of Oregon; University of Oregon; University of Oregon; University of Oregon; University of Alaska, Anchorage; University of Alaska, Anchorage; University of Alaska, Anchorage; University of Alaska, Anchorage; University of Oregon; University of Oregon annp@uoregon.edu

The aquatic contaminant perchlorate is one of the few contaminants known to cause masculinization in some teleost model organisms (stickleback) and feminization in others (zebrafish). How can a single contaminant cause such divergent effects on primary sexual differentiation in different species? To determine the divergent effects of perchlorate exposure on gene expression, we raised 800,000 stickleback embryos for up to one year in four doses of perchlorate, and individuals from the Nadia laboratory strain and a transgenic VASA:GFP (AB) strain of zebrafish in two doses of perchlorate for up to 32 days post fertilization (juvenile stage). In stickleback, perchlorate caused increased embryonic androgen synthesis, increased gamete proliferation in both sexes, and sex-specific changes in primary germ cell apoptosis. In zebrafish, perchlorate exposure from fertilization caused reduced or delayed maturity in primary germ cells. Perchlorate also increased expression of the sodium-iodide symporter (NIS) gene during development in stickleback. A clade of genes closely related to NIS may be important to the systemic response to perchlorate during development, and we are investigating the role of these genes in gonad development using in situ hybridization and qPCR. These results contribute to the understanding of how genetic background and species-specific developmental programs contribute to health outcomes of contaminant exposure, and to the understanding of possible correlated response of evolutionarily related groups of genes (paralogs) to single contaminant exposures during early development.