PrP Polymorphisms Associated with Natural Scrapie Discovered by Denaturing Gradient Gel Electrophoresis

145

113

We investigated the relationships between amino acid polymorphisms of the prion protein (PrP), restriction fragment length polymorphisms (RFLP) of the PrP gene and the incidence of natural scrapie in Japan. Six variant alleles of the PrP gene were found in healthy sheep. Based on the substitutions at codons 112, 136, 154 and 171, these allelic variants were designated PrP MA~Q, PrP TA~Q, PrP Mv~Q, PrP MAHQ, PrP ~ARR and PrP MARry. Each RFLP haplotype (elhl, elh2 or e3hl) consisted of multiple alleles including PrP MARQ. Three of these variant alleles were found in scrapie-affected Suffolk sheep. PrP ~A~Q was associated with high disease incidence, PrP TARQ and PrP MAR~ were associated with low disease incidence. We found that one scrapieaffected Suffolk was homozygous for PrP uARr~ and four prpS°-positive Suffolks carried PrP MvRQ. Both of two scrapie-affected Corriedales and two out of three scrapie-affected cross-breeds between Suffolk and Corriedale carried PrP MA~n, suggesting that this allele associates with high incidence of scrapie in Corriedale and its cross-breeds.

supporting

confidence: 79%

“…were affected with natural scrapie (Laplanche et al, 1993). During an experimental challenge of Cheviots with SSBP/1 in the United States, most of the sheep which developed scrapie carried Val-136, and only a remainder which showed a longer incubation period than did all the other scrapie-positive sheep, did not have Val-136 (Maciulis et al, 1992).…”

mentioning

confidence: 99%

Amino acid polymorphisms of PrP with reference to onset of scrapie in Suffolk and Corriedale sheep in Japan

Ikeda

Horiuchi

Ishiguro

et al. 1995

145

113

“…All of these animals were heterozygous RC "&" . Polymorphisms previously described at codons 112, 137 and 211 (Laplanche et al, 1993 ;Bossers et al, 1996) were not found. The phenylalanine leucine polymorphism at codon 141 was found at a moderate level (" 7 %) in the three types of crossbred sheep, but not in the Spel breed (data not shown).…”

Section: Prp Genotypes Detected In This Studymentioning

confidence: 61%

“…In several breeds, scrapie susceptibility is greatly enhanced by a valine (V) substitution for alanine (A) at codon 136. This polymorphism is very rare in Suffolk and Lacaune sheep (Westaway et al, 1994 ;Clouscard et al, 1995), but of the greatest importance in breeds such as Swaledale, Shetland, Cheviot, Romanov, Texel, Ile de France and Blue du Maine (Laplanche et al, 1993 ;Hunter et al, 1994 ;Westaway et al, 1994 ;Belt et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Prion protein gene polymorphisms in sheep with natural scrapie and healthy controls in Norway.

Tranulis¹,

Osland²,

Bratberg

et al. 1999

Two-hundred and forty healthy sheep and 32 cases of natural scrapie in Norway were analysed for disease-linked polymorphisms in the prion protein (PrP) gene. Scrapie was strongly associated with the presence of a valine polymorphism at codon 136 (V 136 ), as 68n8 % of the cases were homozygous (VV 136 ) and 15n6 % were valine/alanine heterozygous (VA 136 ). All cases were homozygous arginine/arginine at codon 154 (RR 154 ), except two which were homozygous histidine/histidine (HH 154 ). All cases except two were homozygous glutamine/glutamine at codon 171 (QQ 171 ), the two exceptions being heterozygous glutamine/arginine (QR 171 ). More than 80 % of all scrapie cases in Norway have occurred in a Cheviot-related crossbred type of sheep called Rygja. This type of sheep, which is largely restricted to the south-western coast, carries the V 136 allele at a higher frequency than do other breeds of Norwegian sheep. Polymorphisms at codons 138 and 151 are also described.

“…Thus sheep bearing the VRQ residues (at codons 136, 154 and 171) are highly susceptible to the classical form of scrapie, while those bearing ARQ appear to have intermediate susceptibility and homozygous ARR sheep are relatively resistant (Goldmann et al, 1994;Hunter et al, 1993;Laplanche et al, 1993;Maciulis et al, 1992). In addition, there is evidence that the differences in susceptibility between VRQ-and ARQ-bearing sheep is strain-or scrapie-sourcedependent.…”

Section: Introductionmentioning

confidence: 99%

In vitro amplification of PrPSc derived from the brain and blood of sheep infected with scrapie

Thorne

Terry

2008

101

116

Scrapie is a fatal, naturally transmissible, neurodegenerative prion disease that affects sheep and goats and is characterized by the accumulation of a misfolded protein, PrPSc, converted from host-encoded PrPc, in the central nervous system of affected animals. Highly efficient in vitro conversion of host PrPc to PrPSc has been achieved in models of scrapie and in natural prion diseases by protein misfolding cyclic amplification (PMCA). Here, we demonstrate amplification, by serial PMCA, of PrPSc from individual sources of scrapie-infected sheep. Efficiency of amplification was affected by the pairing of the source of PrPSc with the control brain substrate of different genotypes of PrP. In line with previous studies, efficiency of amplification was greatly enhanced with the addition of a synthetic polyanion, polyadenylic acid (PolyA), facilitating rapid detection of low levels of PrPSc from body fluids such as blood. To this end PrPSc was amplified, in a 3 day PMCA assay, from blood leukocyte preparations from VRQ/VRQ scrapie-affected sheep at clinical end point. While PolyA-assisted PMCA resulted in spontaneous conversion of PrPc, we were able to distinguish blood samples from unaffected and affected sheep under controlled conditions. This study demonstrates that highly efficient amplification of PrPSc can be achieved for ovine scrapie from both brain and blood from naturally infected sheep and shows potential applications for improvements in current diagnostics and pre-mortem testing.