Fahong Yu
David Moraga Amador
Timothy A. Bargar
Nancy D. Denslow
Erica K. Brockmeier
2013
<h4>Background</h4>
<p>The eastern mosquitofish (<i>Gambusia holbrooki</i>) has the potential to become a bioindicator organism of endocrine disrupting chemicals (EDCs) due to its androgen-driven secondary sexual characteristics. However, the lack of molecular information on <i>G</i>. <i>holbrooki</i> hinders its use as a bioindicator coupled with biomarker data. While traditional gene-by-gene approaches provide insight for biomarker development, a holistic analysis would provide more rapid and expansive determination of potential biomarkers. The objective of this study was to develop and utilize a mosquitofish microarray to determine potential biomarkers of subchronic androgen exposure. To achieve this objective, two specific aims were developed: 1) Sequence a <i>G</i>. <i>holbrooki</i> cDNA library, and 2) Use microarray analysis to determine genes that are differentially regulated by subchronic androgen exposure in hepatic tissues of 17β-trenbolone (TB) exposed adult female <i>G</i>. <i>holbrooki</i>.</p>
<h4>Results</h4>
<p>A normalized library of multiple organs of male and female <i>G</i>. <i>holbrooki</i> was prepared and sequenced by the Illumina GA IIx and Roche 454 XLR70. Over 30,000 genes with e-value ≤ 10<sup>-4</sup>were annotated and 14,758 of these genes were selected for inclusion on the microarray. Hepatic microarray analysis of adult female <i>G</i>. <i>holbrooki</i> exposed to the vehicle control or 1 μg/L of TB (a potent anabolic androgen) revealed 229 genes upregulated and 279 downregulated by TB (one-way ANOVA, p < 0.05, FDR α = 0.05, fold change > 1.5 and < −1.5). Fifteen gene ontology biological processes were enriched by TB exposure (Fisher’s Exact Test, p < 0.05). The expression levels of<i>17β</i>-<i>hydroxysteroid dehydrogenase 3</i> and <i>zona pellucida glycoprotein 2</i> were validated by quantitative polymerase chain reaction (qPCR) (Student’s t-test, p < 0.05).</p>
<h4>Conclusions</h4>
<p>Coupling microarray data with phenotypic changes driven by androgen exposure in mosquitofish is key for developing this organism into a bioindicator for EDCs. Future studies using this array will enhance knowledge of the biology and toxicological response of this species. This work provides a foundation of molecular knowledge and tools that can be used to delve further into understanding the biology of <i>G</i>. <i>holbrooki</i> and how this organism can be used as a bioindicator organism for endocrine disrupting pollutants in the environment.</p>
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10.1186/1471-2164-14-660
en
BioMed Central
Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (<i>Gambusia holbrooki</i>)
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