Gene expression patterns predict exposure to PCBs in developing Xenopus laevis tadpoles

• Published in: Environmental and molecular mutagenesis Vol. 42; no. 1; pp. 1 - 10
• Main Authors: Jelaso, Anna M., Lehigh-Shirey, Elisabeth, Means, Jay, Ide, Charles F.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 2003; Wiley-Liss
• Subjects: Animals; Aroclor 1254; Behavior, Animal - drug effects; bioindicator; Biological and medical sciences; Chlorodiphenyl (54% Chlorine) - toxicity; development; Dose-Response Relationship, Drug; Environmental Pollutants - toxicity; Freshwater; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Gene Expression Regulation, Developmental - drug effects; Genes. Genome; Genetic Markers - genetics; Larva - anatomy & histology; Larva - drug effects; Larva - metabolism; Longevity - drug effects; Molecular and cellular biology; Molecular genetics; real-time PCR; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Xenopus laevis; Xenopus laevis - physiology; Aroclor 1254; Xenopus laevis; Amphibia; Salientia; Exposure; real-time PCR; Gene expression; Real time; Polymerase chain reaction; bioindicator; Vertebrata; Biphenyl derivatives; Development
• ISSN: 0893-6692; 1098-2280
• DOI: 10.1002/em.10173

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that pose global ecological and human health problems. Although it is well established that PCBs are associated with a variety of adverse health effects in wildlife and in humans, it is often difficult to determine direct cause‐and‐effect relationships between exposure and specific health outcomes. In this study, gene expression signatures were used to relate exposure to PCBs with altered physiological responses and/or specific health effects. Real‐time PCR was used to measure gene expression levels for 10 genes in Xenopus laevis tadpoles (18 days postfertilization, PF) after acute exposure (2 days) to the PCB mixture Aroclor 1254. Specific gene expression signatures correlated with exposure and were predictive of adverse health effects. Exposure to low levels of Aroclor 1254 (5–50 ppb) significantly increased expression of six genes, independent of any health effects; exposure to midlevel concentrations (300–400 ppb) significantly decreased expression levels of two genes, NGF and β‐actin, prior to the onset of observable health effects; exposure to higher doses (500–700 ppb) significantly decreased NGF and β‐actin expression concomitant with the appearance of gross morphological abnormalities, behavioral deficits, and a statistically significant decrease in survival. This study expands upon our previous work that demonstrated an age‐dependent susceptibility to Aroclor 1254 in Xenopus laevis tadpoles and that defined specific gene expression signatures as useful bioindicators of exposure and as predictors of overt or impending health effects. Environ. Mol. Mutagen. 42:1–10, 2003. © 2003 Wiley‐Liss, Inc.