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United States Department of Agriculture

Agricultural Research Service

Research Project: IDENTIFICATION AND CHARACTERIZATION OF GENES AFFECTING COOL AND COLD WATER AQUACULTURE PRODUCTION

Location: Cool and Cold Water Aquaculture Research

Title: TRANSCRIPTOME RESPONSES TO CARBON TETRACHLORIDE AND PYRENE IN THE KIDNEY AND LIVER OF JUVENILE RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Authors
item Krasnov, Aleksei - UNI OF KUOPIO, FINLAND
item Koskinen, Heikki - UNI OF KUOPIO, FINLAND
item Rexroad, Caird
item Afanasyev, Sergey - SECHENOV INST OF EVOLUTIO
item Molsa, Hannu - UNI OF KUOPIO, FINLAND
item Oikari, Aimo - UNI OF JYVASKYLA, FINLAND

Submitted to: Aquatic Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 10, 2005
Publication Date: August 1, 2005
Citation: Krasnov, A., Koskinen, H., Rexroad III, C.E., Afanasyev, S., Molsa, H., Oikari, A. 2005. Transcriptome responses to carbon tetrachloride and pyrene in the kidney and liver of juvenile rainbow trout (oncorhynchus mykiss). Aquatic Toxicology 74: 70-81.

Interpretive Summary: Efforts aimed at the genetic improvement of agriculturally important species include the identification of genes controlling production traits. Stress due to environmental toxicity can adversely affect production traits such as disease resistance, growth, and reproduction. Functional genomic technologies are employed in toxicology research to identify novel diagnostic markers and elucidate molecular mechanisms of toxicity. The recent development of microarray platforms for several fish species widely used in environmental research promotes application of gene expression profiling in aquatic toxicology. We constructed a salmonid cDNA microarray representing 1300 genes to study responses to stressors, toxicity and pathogens. We report the effects of the hepatotoxic compound carbon tetrachloride (CCl4) and pyrene, a model polycyclic aromatic hydrocarbon, on gene expression in juvenile rainbow trout kidneys and livers. Characterization of these genes will benefit scientists working to understand responses to stress at the molecular level.

Technical Abstract: Functional genomic technologies are employed in toxicology research to identify novel diagnostic markers and elucidate molecular mechanisms of toxicity. The recent development of microarray platforms for several fish species widely used in environmental research promotes application of gene expression profiling in aquatic toxicology. We constructed a salmonid cDNA microarray targeted at studies of responses to stressors, toxicity and pathogens. We report the effects of the hepatotoxic compound carbon tetrachloride (CCl4) and pyrene, a model polycyclic aromatic hydrocarbon, on transcriptome of juvenile rainbow trout kidneys and livers. Fish were exposed to sublethal doses for 4 days and expression of 1300 genes measured. Efforts were focused on differentiating between unspecific responses and those that can be regarded as molecular signatures of CCl4 and pyrene toxicity. Expression profiles were analyzed in terms of Gene Ontology categories. Universal reaction to chemical toxicity was observed in metallothionein, HSP90 and mitochondrial proteins of oxidative phosphorylation, which were induced in both tissues. Several genes showed similar responses to both compounds in either kidney or liver; most of which are implicated in hematopoiesis and immune response. Stimulation of mitochondrial and heat shock proteins was greater in the liver whereas genes involved in transcription, humoral immune response and apoptosis were suppressed. Pyrene and CCl4 caused opposite effects on expression of several genes, including HSP-27, macrophage receptor Marco, metalloproteinases (MMP9 and MMP13, and delta-6 fatty acids desaturase. Pyrene affected mainly genes implicated to maintenance of genetic apparatus, immune response, glycolysis, iron homeostasis and ion transport whereas CCl4 impacted genes involved in cellular stress, protein folding and steroid metabolism. Overall, pyrene suppressed a range of protective or acclimative reactions, many of which were stimulated with CCl4. Additionally, microarray analyses indicated adaptive and potentially disadaptive reactions to toxicity. For instance, stimulation of mitochondrial proteins coincided with suppression of catalase and anti-apoptotic L35 ribosomal protein whereas CCl4 down regulated fatty acid metabolism and peroxisomal proteins. A number of candidate markers were identified as our understanding of mechanisms of pyrene and CCl4 toxicity in rainbow trout increased. To promote application of multiple gene expression profiling to ecotoxicological risk assessment, further experiments with chemical mixtures at more long-term exposure settings are required.

Last Modified: 9/1/2014
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