Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2002
Publication Date: April 15, 2002
Citation: Araujo, R.N., Sonstegard, T.S., Zarlenga, D.S., Padilha, T., Gasbarre, L.C. 2002. Expression profile analysis of immune-related genes in cattle infected with ostertagia ostertagi. BARC Poster Day.
Gastrointestinal nematode infections are one of the most economically important endemic infections in cattle raising areas of the world, with Ostertagia ostertagi being the most important in temperate regions. Control of the disease is based principally on the repeated use of anthelmintics. Although the drugs have high efficacy, current anthelmintic use has generated a number of concerns related to the quantity and effects of chemicals on the environment and in the food supply, and the increasing appearance of drug resistant parasites. An attractive alternative for nematode control is the identification of host genes that influence resistance to the parasites and the use of the vast potential of the host to reduce parasite transmission in cattle populations. Microarrays are valuable tools to monitor changes in gene expression. The goal of this research project is to compare the transcript profiles for animals resistant and susceptible to Ostertagia ostertagi infection. For profiling, target sequences for arraying were selected based on importance relative to the immune system and immunologically mediated responses. A list of more than 900 candidate genes was constructed and GenBank was searched to identify sequences corresponding to the desired annotation. For those genes where the bovine sequence was unknown, nucleotide sequence was recovered from those available for other placental mammals. Then, the sequence of these potential orthologs was compared to bovine sequences in dbEST in an attempt to identify bovine clones available from USDA bovine cDNA libraries. Over 400 clones were identified, re-arrayed, and sequenced to validate clone identity. Bovine genes considered important, but not available in dbEST, were cloned by PCR amplification using heterologous primers designed from alignments of available GenBank accessions. After sequence validation, 185 clones were PCR amplified, and these products were purified for arraying onto glass slides. Slides were hybridized using cDNA generated from abomasal RNA. Hybridization results were captured using a Genepix 4000B scanner and the data are currently being analyzed.