title: Marker genes for activation of the RNA interference (RNAi) pathway in the free-living nematode Caenorhabditis elegans and RNAi development in the ovine nematode Teladorsagia circumcincta.
abstract: The nematode Teladorsagia circumcincta is a major cause of parasitic gastroenteritis in sheep in temperate regions. The development of resistance to the major anthelmintic classes used for its control is a threat to small ruminant farming sustainability. Vaccination is a potential alternative control method for this nematode. Gene datasets can be exploited to identify potential vaccine candidates and these validated further by methods such as RNA interference (RNAi) prior to vaccine trials. Previous reports indicate that RNAi in parasitic nematodes is inconsistent and, to date, there are no internal controls that indicate activation of the RNAi pathway in response to double-stranded RNA (dsRNA). The present aims were to determine whether or not the transcription levels of potential marker genes in the RNAi pathway could indicate activation of the pathway in Caenorhabditis elegans and to develop an RNAi platform in T. circumcincta. In C. elegans, transcript levels of three candidate marker genes, Ce-dcr-1 (Dicer), Ce-ego-1 (Enhancer of Glp-One family member) and Ce-rsd-3 (RNAi Spreading Defective), were analysed and results indicated that activation of the pathway had no effect on transcript levels of these genes. In T. circumcincta, two vaccine candidate genes from the Activation-associated Secreted Protein (ASP) family were targets for knockdown. RNAi experiments showed successful silencing of both targets, although inconsistencies in efficacy were observed. After testing a number of parameters that might affect variability, it was found that the length of the storage period of the larvae plays an important role in the consistency of the RNAi results.
authors.affiliation: Moredun Research Institute,Pentland Science Park, Bush Loan,PenicuikEH26 0PZ,Scotland.
authors.forename: T
authors.initials: T
authors.lastname: Tzelos
authors.affiliation: Moredun Research Institute,Pentland Science Park, Bush Loan,PenicuikEH26 0PZ,Scotland.
authors.forename: J B
authors.initials: JB
authors.lastname: Matthews
authors.affiliation: The Roslin Institute and Royal (Dick) School of Veterinary Studies,Easter Bush,Midlothian,EH25 9RG,Scotland.
authors.forename: B
authors.initials: B
authors.lastname: Whitelaw
authors.affiliation: Moredun Research Institute,Pentland Science Park, Bush Loan,PenicuikEH26 0PZ,Scotland.
authors.forename: D P
authors.initials: DP
authors.lastname: Knox
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D005796:Genes; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology*; D014251:Trichostrongyloidea / Q000235:genetics*; D014252:Trichostrongyloidiasis / Q000469:parasitology / Q000662:veterinary*
chemical_list: D015801:Helminth Proteins