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Identifying Universal Fish Biomarker Genes in Response to PCB126 Exposure by Comparative Transcriptomic Analyses
Ira Agrawal1,2, Ai Qi Lee1, Zhiyuan Gong1
1Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore.
Current Issues in Molecular Biology
|August 28, 2024
Summary
Researchers identified common biomarker genes in fish to predict toxicity from water pollutants like polychlorinated biphenyls (PCB126). This enables monitoring of aquatic environments using degenerate PCR primers for diverse fish species.
Area of Science:
- Environmental Toxicology
- Molecular Biology
- Ecotoxicology
Background:
- Water pollution poses significant environmental risks due to persistent, bioaccumulative toxic by-products.
- Current toxicological testing relies on laboratory methods, lacking effective monitoring tools for wild aquatic environments.
- Developing predictive toxicity biomarkers is crucial for assessing environmental contamination in diverse fish species.
Purpose of the Study:
- To identify common biomarker genes for predicting toxicity of chemical contaminants, using 3,3',4,4',5-polychlorinated biphenyl (PCB126) as a model toxicant.
- To validate these biomarker genes across multiple fish species and develop universal PCR primers for broad application in teleost fish.
- To establish a strategy for developing diagnostic PCR arrays for predicting water contamination in wild fish populations.
Main Methods:
- Exposed zebrafish (Danio rerio) and medaka (Oryzias latipes) to PCB126 and performed RNA-sequencing to obtain liver transcriptomic data.
- Conducted comparative transcriptomic analyses to identify conserved up- and downregulated genes between the two species.
- Validated nine selected biomarker genes in Mozambique tilapia (Oreochromis mossambicus) and designed degenerate PCR primers tested in multiple species, including guppy (Poecilia reticulata).
Main Results:
- Comparative transcriptomics revealed conserved gene expression changes in zebrafish and medaka upon PCB126 exposure, validating the approach for biomarker selection.
- Nine selected biomarker genes demonstrated consistent responses across zebrafish, medaka, and Mozambique tilapia.
- Degenerate PCR primers successfully amplified biomarker genes in at least 50% of tested fish species, indicating broad applicability.
Conclusions:
- The study presents a promising strategy for identifying common biomarker genes applicable to teleost fish for predictive toxicity assessment.
- The developed degenerate PCR primers and biomarker gene set offer a foundation for creating diagnostic PCR arrays to monitor water contamination in wild fish.
- This approach enhances the ability to assess environmental health by providing tools for detecting toxic substances in aquatic ecosystems.
