title: Gene expression profiling of naïve sheep genetically resistant and susceptible to gastrointestinal nematodes.
abstract: BACKGROUND
  Gastrointestinal nematodes constitute a major cause of morbidity and mortality in grazing ruminants. Individual animals or breeds, however, are known to differ in their resistance to infection. Gene expression profiling allows us to examine large numbers of transcripts simultaneously in order to identify those transcripts that contribute to an animal's susceptibility or resistance.
  
  
  RESULTS
  With the goal of identifying genes with a differential pattern of expression between sheep genetically resistant and susceptible to gastrointestinal nematodes, a 20,000 spot ovine cDNA microarray was constructed. This array was used to interrogate the expression of 9,238 known genes in duodenum tissue of four resistant and four susceptible female lambs. Naïve animals were used in order to look at genes that were differentially expressed in the absence of infection with gastrointestinal nematodes. Forty one unique known genes were identified that were differentially expressed between the resistant and susceptible animals. Northern blotting of a selection of the genes confirmed differential expression. The differentially expressed genes had a variety of functions, although many genes relating to the stress response and response to stimulus were more highly expressed in the susceptible animals.
  
  
  CONCLUSIONS
  We have constructed the first reported ovine microarray and used this array to examine gene expression in lambs genetically resistant and susceptible to gastrointestinal nematode infection. This study indicates that susceptible animals appear to be generating a hyper-sensitive immune response to non-nematode challenges. The gastrointestinal tract of susceptible animals is therefore under stress and compromised even in the absence of gastrointestinal nematodes. These factors may contribute to the genetic susceptibility of these animals.
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand. orla.keane@agresearch.co.nz
authors.forename: Orla M
authors.initials: OM
authors.lastname: Keane
authors.forename: Amonida
authors.initials: A
authors.lastname: Zadissa
authors.forename: Theresa
authors.initials: T
authors.lastname: Wilson
authors.forename: Dianne L
authors.initials: DL
authors.lastname: Hyndman
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Greer
authors.forename: David B
authors.initials: DB
authors.lastname: Baird
authors.forename: Alan F
authors.initials: AF
authors.lastname: McCulloch
authors.forename: Allan M
authors.initials: AM
authors.lastname: Crawford
authors.forename: John C
authors.initials: JC
authors.lastname: McEwan
mesh_terms: D000818:Animals; D001665:Binding Sites; D004386:Duodenum / Q000378:metabolism; D005260:Female; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D005767:Gastrointestinal Diseases / Q000235:genetics / Q000469:parasitology / Q000662:veterinary*; D020869:Gene Expression Profiling; D020022:Genetic Predisposition to Disease; D007113:Immunity, Innate; D009349:Nematode Infections / Q000235:genetics / Q000469:parasitology / Q000662:veterinary*; D011401:Promoter Regions, Genetic; D012756:Sheep; D012757:Sheep Diseases / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D020558:GTP Phosphohydrolases