Transcriptomics

Dataset Information

3

Gene expression changes in the female zebrafish (Danio rerio) brain in response to acute exposure to methylmercury


ABSTRACT: Methylmercury (MeHg) is a potent neurotoxin and endocrine disruptor that accumulates in aquatic systems. Previous studies have shown suppression of hormone levels in both male and female fish, suggesting effects on gonadotropin regulation in the brain. We investigated the gene expression profile in adult female zebrafish whole brain induced by acute (96 hr) MeHg exposure. Fish were exposed by injection to 0 or 0.5 µg MeHg/g. Gene expression changes in the brain were examined using a two-color 22,000 feature zebrafish microarray. At a significance level of p<0.01, 79 genes were up-regulated and 76 genes were down-regulated in response to MeHg exposure. Individual genes exhibiting altered expression in response to MeHg exposure implicate effects on glutathione metabolism and GABA-A receptors in the mechanism of MeHg neurotoxicity. Gene ontology (GO) terms significantly enriched among altered genes included protein folding, cell redox homeostasis, and steroid biosynthetic process. The most affected biological functions were related to the nervous system development and function, as well as lipid metabolism and molecular transport. These results support the involvement of oxidative stress and effects on protein structure in the mechanism of action of MeHg in the female brain. Future studies will compare the gene expression profile induced in response to MeHg with that induced by other toxins and investigate responsive genes as potential biomarkers of MeHg exposure. Wild-type strain AB-1 zebrafish (Zebrafish International Resource Center, University of Oregon, Eugene, OR) were cultured at the Columbia Environmental Research Center (CERC), USGS, for MeHg exposures. Adult female zebrafish were injected with 0 μg/g or 0.5 μg/g MeHg in 2 µL Na2CO3 (pH 6.98)/g body weight. After 96 hr, fish were anesthetized using ethyl 3-aminobenzoate methanesulfonate (MS-222, Sigma, St. Louis, MO). Whole brains were removed, flash frozen with liquid nitrogen and stored at 80°C. For the microarray experiment, two zebrafish brains were pooled per sample. Four pooled samples were taken from fish treated with 0.5 μg/g of MeHg, and the other five were taken from control fish treated with sodium carbonate. Array hybridizations were performed using a reference design, where each sample was compared to a reference sample. The reference sample consisted of equal amounts of RNA from control and treated female brains. Five replicates for the control and four replicates for the treated were analyzed. cDNA synthesis, cRNA labeling, amplification and hybridization were performed following the manufacturer’s kits and protocols (Agilent Low RNA Input Fluorescent Linear Amplification Kit and Agilent 60-mer oligo microarray processing protocol; Agilent, Palo Alto, CA).

ORGANISM(S): Danio rerio  

SUBMITTER: Pope Marie   Garcia-Reyero Natalia  Martyniuk Chris  Denslow D Nancy  Knoebl Iris  Richter A Catherine  Tillitt E Donald  Wright-Osment Maureen  Natalia Vinas 

PROVIDER: E-GEOD-22662 | ArrayExpress | 2010-09-30

SECONDARY ACCESSION(S): GSE22662PRJNA127997

REPOSITORIES: GEO, ArrayExpress

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Gene expression changes in female zebrafish (Danio rerio) brain in response to acute exposure to methylmercury.

Richter Catherine A CA   Garcia-Reyero Natàlia N   Martyniuk Chris C   Knoebl Iris I   Pope Marie M   Wright-Osment Maureen K MK   Denslow Nancy D ND   Tillitt Donald E DE  

Environmental toxicology and chemistry 20110201 2


Methylmercury (MeHg) is a potent neurotoxicant and endocrine disruptor that accumulates in aquatic systems. Previous studies have shown suppression of hormone levels in both male and female fish, suggesting effects on gonadotropin regulation in the brain. The gene expression profile in adult female zebrafish whole brain induced by acute (96 h) MeHg exposure was investigated. Fish were exposed by injection to 0 or 0.5 µg MeHg/g. Gene expression changes in the brain were examined using a 22,000-fe  ...[more]

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