ToxSci Advance Access originally published online on November 2, 2005
Toxicological Sciences 2006 89(2):524-534; doi:10.1093/toxsci/kfj033
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dynamic Gene Expression Changes Precede Dioxin-Induced Liver Pathogenesis in Medaka Fish

* Integrated Toxicology Program and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708; and
Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606
Received August 25, 2005; accepted October 23, 2005
A major challenge for environmental genomics is linking gene expression to cellular toxicity and morphological alteration. Herein, we address complexities related to hepatic gene expression responses after a single injection of the aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) and illustrate an initial stress response followed by cytologic and adaptive changes in the teleost fish medaka. Using a custom 175-gene array, we find that overall hepatic gene expression and histological changes are strongly dependent on dose and time. The most pronounced dioxin-induced gene expression changes occurred early and preceded morphologic alteration in the liver. Following a systematic search for putative Ah response elements (AHREs) (5'-CACGCA-3') within 2000 bp upstream of the predicted transcriptional start site, the majority (87%) of genes screened in this study did not contain an AHRE, suggesting that gene expression was not solely dependent on AHRE-mediated transcription. Moreover, in the highest dosage, we observed gene expression changes associated with adaptation that persisted for almost two weeks, including induction of a gene putatively identified as ependymin that may function in hepatic injury repair. These data suggest that the cellular response to dioxin involves both AHRE- and non-AHRE-mediated transcription, and that coupling gene expression profiling with analysis of morphologic pathogenesis is essential for establishing temporal relationships between transcriptional changes, toxicity, and adaptation to hepatic injury.
Key Words: medaka; dioxin; liver; aryl hydrocarbon receptor; gene expression; transcription.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
D. C. Volz, S. W. Kullman, D. L. Howarth, R. C. Hardman, and D. E. Hinton Protective Response of the Ah Receptor to ANIT-Induced Biliary Epithelial Cell Toxicity in See-Through Medaka Toxicol. Sci., April 1, 2008; 102(2): 262 - 277. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Wintz, L. J. Yoo, A. Loguinov, Y.-Y. Wu, J. A. Steevens, R. D. Holland, R. D. Beger, E. J. Perkins, O. Hughes, and C. D. Vulpe Gene Expression Profiles in Fathead Minnow Exposed to 2,4-DNT: Correlation with Toxicity in Mammals Toxicol. Sci., November 1, 2006; 94(1): 71 - 82. [Abstract] [Full Text] [PDF] |
||||
