P1.18 Wednesday, Jan. 4 Identification of Key Members of the Aryl Hydrocarbon Receptor (AHR) Pathway and Related Oxidative Stress Genes from the American Oyster, Crassostrea virginica ANSORGE, Kirsten*; CRANE, Daniel; CUNNINGHAM, Charles; JENNY, Matthew J; University of Alabama; University of Alabama; University of New Mexico; University of Alabama email@example.com
Oysters (Crassostrea virginica) were one of the major estuarine species to be impacted by the Deepwater Horizon oil spill which released ~5 million barrels of crude oil into the Gulf of Mexico in the Spring-Summer of 2010. Although oysters are routinely used as model estuarine organisms for environmental monitoring, we know very little about their molecular response to hydrocarbon exposure. To identify potential biomarker genes, we exposed oysters to crude oil (100 ppm) or crude oil and dispersant (1 ppm) for four days. Digestive gland and gill tissues were dissected for RNA isolation. Total RNA from control and oil-exposed oysters were pooled and each tissue RNA sample was sequenced using a 454 Genome Sequencer. ~700,000 sequences reads were generated from each tissue sample. The sequences were assembled and blasted against the NCBI nonredundant database using the blastx algorithm. From these results several candidate genes were selected for characterization, including putative clones for the aryl hydrocarbon receptor (AHR), aryl hydrocarbon receptor nuclear translocator (ARNT), and three candidate cytochrome P450 1A (CYP1A) transcripts. Although CYP1A genes are classic molecular biomarkers of hydrocarbon exposure in vertebrates, very little is known regarding invertebrate CYP1A genes and their response to environmental pollutants. In addition to the AHR pathway genes several classic oxidative stress genes were identified, including superoxide dismutase, catalase, and glutathione reductase. Gene expression studies with both controlled oil exposures (0.1 to 100 ppm) and oysters collected from oil-impacted reefs are currently being used to assess the feasibility of these genes serving as biomarkers of crude oil exposure.