Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Workshop: Cattle/Sheep
Transmissible spongiform encephalopathies (TSE) or prion diseases, such as Creutzfeldt Jakob, BSE or scrapie are characterized by the accumulation of a special form of the protein PrP (PrPsc) in the Central Nervous System (e.g. Aguzzi and Heppner, Cell Death and Differentiation, 2000). The PrP gene is known to influence the susceptibility to TSEs in some species, including mouse, Human and sheep (e.g. Hunter et al, Arch. Virol. 2000). A detailed analysis is presented about the effects of PrP alleles on susceptibility to natural scrapie, incubation time and carrier state, based on data collected in a sheep experimental farm highly infected by scrapie since 1991 and in the field. The carrier state is evaluated from immuno-histo-chemical search of PrPsc in various organs, in particular CNS and tonsils. Our observations add arguments to the full resistance of sheep homozygous for one of the alleles (coding for Alanine, Arginine and Arginine at codons 136, 154 and 171) and tend to show that these animals do not carry infectivity. A systematic search for QTL modulating the effect of the PrP gene, based on two half sib families homogeneous for a susceptible genotype breed in highly infected conditions is reported.