Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Genome Sequencing & ESTs
            

EXPRESSED SEQUENCE TAG ANALYSIS OF HEMOCYTES AND EMBRYOS FROM THE AMERICAN OYSTER, CRASSOSTREA VIRGINICA, USED TO IDENTIFY POTENTIAL BIOMARKERS

¹ Marine Biomedicine and Environmental Science, Medical University of South Carolina, 221 Fort Johnson Rd, Charleston, SC, 29412, USA

² Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 171 Ashley Ave., Charleston, SC, 29425, USA

³ Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Rd., Charleston, SC, 29412, USA

⁴ Department of Cell Biology and Anatomy, Medical University of South Carolina, 171 Ashley Ave., Charleston, SC, 29425, USA

⁵ Belle W. Baruch Institute for Coastal Research, University of South Carolina, P.O. Box 1630, Georgetown, SC 29442, USA

Crassostrea virginica, an ecologically and economically important species, has experienced major declines in natural populations for a variety of reasons including over-harvesting, loss of habitat, degradation of water quality and greater prevalence of disease causing agents. Therefore, a functional genomics approach has been initiated to increase our understanding of the effects of environmental pressures, natural and anthropogenic in origin, on organism health. A pilot program was initiated to identify genes potentially involved in stress responses for use as bio-indicators of exposure to environmental pollutants, and to toxic and infectious agents. A PCR-based method was used to construct cDNA libraries from pooled embryos and the hemocytes of a single adult individual. To date, approximately 1000 clones (expressed sequence tags, ESTs) have been sequenced. Diversity analysis indicates that 363 and 286 unique genes were identified from the hemocyte and embryo libraries, respectively. Although both libraries had a minimal percentage of genes with known or potential immune function (2.7% and 3.8% for the embryo and hemocyte libraries, respectively), several potential biomarkers include an antimicrobial peptide, recognition molecules (lectin receptors), and proteinases and proteinase inhibitors. Additional genes of interest include metallothioneins, oxidative stress-related genes, and heat shock factors. Furthermore, based on comparisons with the NCBI non-redundant database, 56.4% and 38.7% of the ESTs from hemocytes and embryos, respectively, are either completely novel or related to genes of unknown function indicating the potential for new gene discovery. Supported by NMFS (NA97FL0377), SC Sea Grant Consortium (R/F-1C), SCDNR & NSF (EPS0083102; MCB9807531), and NOAA, NOS (NA060A0675).