Plant, Animal & Microbe Genomes X Conference

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

Poster: Genome Sequencing & ESTs
            

EST ANALYSIS REVEALS SUBSTANTIAL DIVERSITY OF PENAEIDIN ANTIMICROBIAL PEPTIDES

¹ Marine Biomedicine and Environmental Sciences Program, Medical University of South Carolina, Charleston, SC 29425 USA

² Marine Resources Research Institute, South Carolina Department of Natural Resources, Charleston, SC 29412 USA

Penaeidins are a unique family of antimicrobial peptides with both proline and cysteine-rich domains that were identified and characterized as peptides in the hemolymph of the Pacific white shrimp, Litopenaeus vannamei. Characterization, by random EST collection, of cDNA clones from a hemocyte library of L. vannamei revealed the existence of a fourth class of penaeidins, and also revealed heretofore unexpected variability within a single penaeidin class. We report here the results of a detailed investigation of penaeidin diversity in two species of shrimp, L. vannamei and L. setiferus (Atlantic white shrimp). This study revealed that (1) the novel penaeidin class, designated penaeidin 4, is present in both L. vannamei and L. setiferus, (2) all classes of penaeidins are expressed in an individual shrimp, (3) penaeidin sequence variability (especially of class 3), within and between individuals, cannot be explained as simple allelic polymorphism, (4) penaeidins are encoded by a small gene family or by a complex multi-exon locus, and (5) based on phylogenetic analysis, penaeidins fall into three classes. The results of our analysis imply that classes 1 and 2 are united, with classes 3 and 4 remaining distinct. All classes of penaeidin were present prior to the speciation of L. vannamei and L. setiferus. Work supported by awards from the NSF (EPSCoR EPS0083102) and from the National Ocean Services.