Submitted to: Veterinary Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/13/2009
Publication Date: 5/26/2009
Citation: Abubucker, S., Zarlenga, D.S., Martin, J., Yin, Y., Wang, Z., Mccarter, J.P., Gasbarre, L.C., Wilson, R.K., Mitreva, M. 2009. The transcriptomes of the cattle parasitic nematode Ostertagia ostartagi. Veterinary Parasitology. 162:89-99. Interpretive Summary: Little is known of the structure, organization and content of nematode genomes beyond that of Caenorhabditis elegans. In particular, a dearth of information has been generated on parasitic nematodes and in particular those infectious for cattle that are highly pathogenic. Ostertagi ostertagi is one such nematode that contributes substantially to the cost of raising cows. Herein we present the first comprehensive analysis of genes expressed in the parasite O. ostertagi using genetic material from all three major developmental stages. Results demonstrate that 66% of the most abundantly expressed genes have orthologues in C. elegans and that conserved biological pathways are in many instances conserved among the broader group of Metazoa. These data will form the foundation for sequencing the entire genome, and generate a comparative framework upon which the entire group of gastrointestinal nematode species infecting ruminants can be referenced. This data will hopefully lead to identifying genetic markers for key phenotypic traits among this group of parasites.
Technical Abstract: Ostertagia ostertagi is a gastrointestinal parasitic nematode that affects cattle and leads to a loss of production. In this study, we present the first large-scale genomic survey of O. ostertagi by the analysis of expressed transcripts from three stages of the parasite: third-stage larvae, fourth-stage larvae and adult worms. Using an in silico approach, 2,284 genes were identified from over 7,000 expressed sequence tags and abundant transcripts were analyzed and characterized by their functional profile. Of the 2,284 genes, 66% had similarity to other known or predicted genes while the rest were novel and potentially represent genes specific to the species and/or stages. Furthermore, a subset of the novel proteins were structurally annotated and assigned putative function based on orthologs in C. elegans and corresponding RNA interference phenotypes. Hence, over 70% of the genes were annotated using protein sequences, domains and pathway databases. Differentially expressed transcripts from the two larval stages and their functional profiles were also studied leading to a more detailed understanding of the parasite’s life-cycle. The identified transcripts are a valuable resource for genomic studies of O. ostertagi and can facilitate the design of control strategies and vaccine programs.