The association between 171 K polymorphism and resistance against scrapie affection in Greek dairy sheep

Boukouvala, Evridiki; Gelasakis, Athanasios Ι.; Kanata, Ειrini; Fragkiadaki, Eirini; Giadinis, Nektarios D.; Palaska, Vayia; Christoforidou, Sofia; Sklaviadis, Theodoros; Ekateriniadou, Loukia

doi:10.1016/j.smallrumres.2018.01.016

Cited by 5 publications

(6 citation statements)

References 34 publications

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“…Real-Time PCR is fast, sensitive and suitable for SNP detection. This method has been also used in sheep for the detection of polymorphisms at codons 136, 154 and 171 in the PRNP gene [ 37 ]. Each SNP Genotyping Assay consisted of a mix of sequence-specific forward and reverse primers to amplify the polymorphic sequence of interest and two TaqMan ® MGB (minor groove binder) probes, FAM (6-carboxyfluorescein) and VIC (2′-chloro-7′phenyl-1,4-dichloro-6-carboxy-fluorescein) dye-labeled to detect the amplified product ( Table 1 ).…”

Section: Methodsmentioning

confidence: 99%

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Vouraki

Gelasakis²,

Alexandri

et al. 2018

PLoS ONE

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Polymorphisms at PRNP gene locus have been associated with resistance against classical scrapie in goats. Genetic selection on this gene within appropriate breeding programs may contribute to the control of the disease. The present study characterized the genetic profile of codons 146, 211 and 222 in three dairy goat breeds in Greece. A total of 766 dairy goats from seven farms were used. Animals belonged to two indigenous Greek, Eghoria (n = 264) and Skopelos (n = 287) and a foreign breed, Damascus (n = 215). Genomic DNA was extracted from blood samples from individual animals. Polymorphisms were detected in these codons using Real-Time PCR analysis and four different Custom TaqMan® SNP Genotyping Assays. Genotypic, allelic and haplotypic frequencies were calculated based on individual animal genotypes. Chi-square tests were used to examine Hardy-Weinberg equilibrium state and compare genotypic distribution across breeds. Genetic distances among the three breeds, and between these and 30 breeds reared in other countries were estimated based on haplotypic frequencies using fixation index FST with Arlequin v3.1 software; a Neighbor-Joining tree was created using PHYLIP package v3.695. Level of statistical significance was set at P = 0.01. All scrapie resistance-associated alleles (146S, 146D, 211Q and 222K) were detected in the studied population. Significant frequency differences were observed between the indigenous Greek and Damascus breeds. Alleles 222K and 146S had the highest frequency in the two indigenous and the Damascus breed, respectively (ca. 6.0%). The studied breeds shared similar haplotypic frequencies with most South Italian and Turkish breeds but differed significantly from North-Western European, Far East and some USA goat breeds. Results suggest there is adequate variation in the PRNP gene locus to support breeding programs for enhanced scrapie resistance in goats reared in Greece. Genetic comparisons among goat breeds indicate that separate breeding programs should apply to the two indigenous and the imported Damascus breeds.

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Section: Methodsmentioning

confidence: 99%

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Vouraki

Gelasakis²,

Alexandri

et al. 2018

PLoS ONE

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“…The authors reported that K171 was the second most resistant allele after arginine (R > K > H > Q). 6 Evaluation of IHC-stained tissues from IC-inoculated sheep revealed intergenotypic differences in PrP Sc phenotypes (pattern and distribution). White matter immunolabeling was largely present in the KK and QK genotype, contrasting a relative absence in sheep with the QQ genotype.…”

Section: Discussionmentioning

confidence: 99%

“…14,21,32 However, little is known about the contribution of lysine (K) other than the presence of naturally occurring scrapie affecting heterozygous K171 sheep in Greek and Italian sheep. 1,6 K171 has a relatively higher incidence in some Mediterranean breeds and also occurs in other breeds seen in the United States, including Barbado, Barbado/St Croix, Dorper, and Suffolk crosses. 2,17 Nonrandom sampling of flocks in the United States has also identified the polymorphism in American Blackbelly, Black Hawaiian, Painted Desert, and Texas Dall sheep (D. Sutton and D. Norden, USDA APHIS, personal communication, unpublished data, 2017).…”

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Sheep With the Homozygous Lysine-171 Prion Protein Genotype Are Resistant to Classical Scrapie After Experimental Oronasal Inoculation

et al. 2018

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Scrapie is a fatal neurodegenerative disease of sheep resulting from the accumulation of a misfolded form of the prion protein (PrPSc). Polymorphisms in the host prion protein gene ( PRNP) can affect susceptibility to the scrapie agent. Lysine (K) at codon 171 of PRNP is an inadequately characterized, naturally occurring polymorphism in sheep. We inoculated Barbado sheep with PRNP genotypes QQ171, QK171, or KK171 by either the intracranial (IC, n = 2–7 per genotype) or oronasal (ON, n = 5 per genotype) routes with a scrapie isolate to investigate the effect of lysine at codon 171 on susceptibility. When neurologic signs were observed or at the end of the experiment (70 months postinoculation [MPI]), sheep were necropsied and tissue collected for histopathologic, immunohistochemical, enzyme immunoassay and Western blot examination for PrPSc. All genotypes of sheep developed scrapie after IC inoculation. After ON inoculation, sheep with the QK171 genotype had prolonged incubation periods compared to the QQ genotype. During the experiment, 2 of 5 of the ON-inoculated QK genotype sheep developed neurologic signs and had PrPSc in the brain. The other 3 of 5 sheep were asymptomatic at 70 MPI but had detectable PrPSc in peripheral tissues. None of the ON-inoculated sheep of the KK171 genotype developed signs or had detectable PrPSc. Our experiments demonstrate that sheep with the KK171 genotype are resistant to scrapie via oronasal exposure and that sheep with the QK171 genotype have prolonged incubation relative to QQ171 sheep. The K171 prion protein allele may be useful to enhance scrapie resistance in certain breeds of sheep.

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“…Despite these three codons having a strong association with CS, codon 171 has a greater influence compared to the other two codons, where homozygous QQ sheep are susceptible to scrapie and the RR genotype confers resistance ( Table 1 ) [ 13 ]. In 2003, a novel variation was detected in codon 171 (lysine-K) by Guo et al (2003) [ 52 ] and later, Boukouvala et al (2018) [ 53 ] reported that dairy sheep with K171 showed a 75% reduction in the risk of developing scrapie when compared with individuals with Q171. Recently, Cassmann et al (2019) [ 14 ] showed that individuals homozygous for K171 (ARK/ARK) were resistant to CS after oronasal inoculation with PrP Sc .…”

Section: Neuropathologymentioning

confidence: 99%

Neuropathology of Animal Prion Diseases

et al. 2021

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Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are a fatal group of infectious, inherited and spontaneous neurodegenerative diseases affecting human and animals. They are caused by the conversion of cellular prion protein (PrPC) into a misfolded pathological isoform (PrPSc or prion- proteinaceous infectious particle) that self-propagates by conformational conversion of PrPC. Yet by an unknown mechanism, PrPC can fold into different PrPSc conformers that may result in different prion strains that display specific disease phenotype (incubation time, clinical signs and lesion profile). Although the pathways for neurodegeneration as well as the involvement of brain inflammation in these diseases are not well understood, the spongiform changes, neuronal loss, gliosis and accumulation of PrPSc are the characteristic neuropathological lesions. Scrapie affecting small ruminants was the first identified TSE and has been considered the archetype of prion diseases, though atypical and new animal prion diseases continue to emerge highlighting the importance to investigate the lesion profile in naturally affected animals. In this report, we review the neuropathology and the neuroinflammation of animal prion diseases in natural hosts from scrapie, going through the zoonotic bovine spongiform encephalopathy (BSE), the chronic wasting disease (CWD) to the newly identified camel prion disease (CPD).

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The association between 171 K polymorphism and resistance against scrapie affection in Greek dairy sheep

Cited by 5 publications

References 34 publications

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Sheep With the Homozygous Lysine-171 Prion Protein Genotype Are Resistant to Classical Scrapie After Experimental Oronasal Inoculation

Neuropathology of Animal Prion Diseases

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The association between 171 K polymorphism and resistance against scrapie affection in Greek dairy sheep

Cited by 5 publications

References 34 publications

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Sheep With the Homozygous Lysine-171 Prion Protein Genotype Are Resistant to Classical Scrapie After Experimental Oronasal Inoculation

Neuropathology of Animal Prion Diseases

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The association between 171 K polymorphism and resistance against scrapie affection in Greek dairy sheep