Search Results (53)

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative diseases caused by the misfolding of proteins generated in the exon 3 region of the prion protein gene (PRNP). Recent investigations using protein misfolding cyclic amplification assays indicated that some canids displayed a low susceptibility to TSE due to a specific nonsynonymous substitution (human: N159D/E; canid: N163D/E; alignment herein: N302D/E) in the prion protein that may confer protection against prion seeding activity and propagation. To examine the molecular evolution underlying this observation, we determined the mammalian taxonomic distribution of the N159D/E substitution in 882 PRNP sequences representing 26 Orders, 132 families, and 686 species. Two families each in Carnivora (Canidae and Mustelidae) and Chiroptera (Mormoopidae and Vespertilionidae), and one family each in Artiodactyla (Moschidae) and Rodentia (Erethrizontidae), possessed N159D/E that has been reported to confer resistance to TSEs. Although no direct evidence linked a pattern of resistance (phylogenetic relatedness, geographic location, etc.) in these diverse species, it may be that coevolutionary pressures led 53 of the examined 686 species (1 domestic species, 52 wild species) to possess N159D/E. Therefore, the presence of N159D/E may not be the only factor in determining sensitivity to prion diseases; consequently, a more detailed investigation into the 53 species, such as knockout experiments, is warranted. Full article

Chronic wasting disease (CWD) is a prion disease of cervids marked by growing strain diversity and variation in host susceptibility. Central to this complexity are prion protein gene (Prnp) polymorphisms, which can modulate pathogenesis by altering the ability of cellular prion protein (PrP^C) to misfold into infectious prions (PrP^Sc), or by promoting the emergence of novel strains. Studies in cervids and transgenic rodent models demonstrate that individual polymorphisms influence PrP stability, conversion efficiency, and the selection of PrP^Sc conformers, with most variants conferring partial resistance but none offering complete protection. These host–strain interactions define transmission barriers and disease phenotype. Understanding how Prnp genotypes shape CWD strain diversity is essential for predicting transmission dynamics, refining surveillance, and assessing zoonotic potential as the disease continues to expand geographically and genetically. Full article

Scrapie (classical and atypical) susceptibility in sheep is strongly influenced by PRNP gene polymorphisms. In Portugal, limited data exist for native breeds such as Serra da Estrela, despite their relevance to animal conservation and food production. The full coding region of PRNP gene of 92 Serra da Estrela sheep was sequenced and SNP frequencies were analysed. The predicted functional impact of nonsynonymous SNPs was assessed using PolyPhen-2 and AMYCO. A total of 27 SNPs were identified, including 20 nonsynonymous variants. Thirteen major haplotypes were observed. The ARR allele, which provides resistance to classical scrapie, was present in 58.7% of the population, with 18.5% of animals being homozygous. Several previously unreported SNPs were identified, and their impact on prion protein aggregation propensity and structure was explored. The high frequency of the ARR allele without full ARR fixation suggests that no selective breeding for scrapie resistance has been applied. These results support the adoption of gradual selection strategies that preserve genetic variability and promote farmer compliance, while increasing classical and atypical scrapie resistance. Full article

Background/Objectives: The normal cellular prion protein (PrP^C) is a cell-surface glycoprotein, mainly localised in neurons of the central nervous system (CNS). The human PRNP gene encodes 253 amino acid residues of precursor PrP^C. Several studies that investigated the role of PRNP and PrP^C in placental mammals, such as humans and mice, failed to reveal its exact function. Methods: In this study, we sequenced and characterised the PRNP gene and PrP^C of the marsupial, P. calura, as a strategy to gain molecular insights into its structure and physicochemical properties. Placentals are separated from marsupials by approximately 125 million years of independent evolution. Results: Standard Western blotting analysis of PrP^C phascogale displayed the typical un-, mono-, and di-glycosylated bands recognized in placentals. Furthermore, we showed that phascogale PRNP gene has two exons, similar to all the marsupials and placentals of the PRNP genes studied. Of note, the phascogale PRNP gene contained distinctive repeats in the PrP^C tail region comparable to the closely related Tasmanian devil (Sarcophilus harrisii) and more distantly related to the grey short-tailed opossum (Monodelphis domestica), common wombat (Vombatus ursinus), and Tammar wallaby (Macropus eugenii); however, its specific composition and numbers were different from placentals. Of importance, comparisons of the phascogale’s PrP^C physicochemical properties with other monotremes, marsupials, and placentals confirmed the Monotremata–Marsupialia–Placentalia evolutionary distance. We found that the protein instability index, a method used to predict the stability of a protein in vivo (Stable: <40; Instable >40), showed that the PrP^C of all marsupials tested, including phascogale, were highly stable compared with the birds, reptiles, amphibians, and fish that were shown to be highly unstable. However, the instability index predicted that all placental species, including human (Homo sapiens), mouse (Mus musculus), bank vole (Myodes glareolus), rhinoceros (Rhinocerotidae), dog (Canis lupus familiaris), flying fox (Pteropus vampyrus), whale (Physeter catodon), cattle (Bos taurus), and sheep (Ovis aries), were either slightly unstable or nearly unstable. Further, our analysis revealed that despite their predicted high PrP^C stability, P. calura exhibited substantial N-terminal disorder (53.76%), while species with highly unstable PrP^Cs based on their instability index, such as Danio rerio, Oryzias latipes, and Astyanax mexicanus, displayed even higher levels of N-terminal disorder (up to 75.84%). These findings highlight a discrepancy between overall predicted stability and N-terminal disorder, suggesting a potential compensatory role of disorder in modulating prion protein stability and function. Conclusions: These results suggest that the high stability of marsupial prion proteins indicates a vital role in maintaining protein homeostasis; however more work is warranted to further depict the exact function. Full article

Prion diseases are fatal neurological disorders characterized by abnormal protein accumulation in the brain, leading to neurodegeneration, dementia, and ataxia. Sporadic Creutzfeldt–Jakob disease (sCJD), the most common form, accounts for 80–90% of cases and progresses rapidly, with most patients surviving <6 months to a year after symptom onset, indicating the importance of early diagnosis. The disease is classified into six subtypes based on PRNP gene polymorphisms, with differences in protein degradation patterns contributing to the diversity of clinical symptoms. However, diagnosis remains challenging because of the variability in clinical presentation and disease duration. Traditional diagnostic criteria established by the World Health Organization (WHO) rely on clinical findings, electroencephalogram, and cerebrospinal fluid tests, such as the 14-3-3 protein assay. However, these criteria require pathological confirmation, often delaying diagnosis. The recently proposed Hermann’s criteria represent a significant advancement by incorporating newer biomarkers, including magnetic resonance imaging, real-time quaking-induced conversion assay, tau protein, and neurofilament light chain. These criteria improve diagnostic sensitivity and specificity but have a slightly higher risk of false positives. This review compares the effectiveness of these biomarkers with the WHO criteria and highlights the importance of early diagnosis for improving patient care. Full article

Prion diseases are fatal neurodegenerative diseases that can be transmitted by infectious protein particles, PrP^Scs, encoded by the endogenous prion protein gene (PRNP). The origin of prion seeds is unclear, especially in non-human hosts, and this identification is pivotal to preventing the spread of prion diseases from host animals. Recently, an abnormally high amyloid propensity in prion proteins (PrPs) was found in a frog, of which the genetic variations in the PRNP gene have not been investigated. In this study, genetic polymorphisms in the PRNP gene were investigated in 194 Dybowski’s frogs using polymerase chain reaction (PCR) and amplicon sequencing. We carried out in silico analyses to predict functional alterations according to non-synonymous single nucleotide polymorphisms (SNPs) using PolyPhen-2, PANTHER, SIFT, and MutPred2. We used ClustalW2 and MEGA X to compare frog PRNP and PrP sequences with those of prion-related animals. To evaluate the impact of the SNPs on protein aggregation propensity and 3D structure, we utilized AMYCO and ColabFold. We identified 34 novel genetic polymorphisms including 6 non-synonymous SNPs in the frog PRNP gene. The hydrogen bond length varied at codons 143 and 207 according to non-synonymous SNPs, even if the electrostatic potential was not changed. In silico analysis predicted S143N to increase the aggregation propensity, and W6L, C8Y, R211W, and L241F had damaging effects on frog PrPs. The PRNP and PrP sequences of frogs showed low homology with those of prion-related mammals. To the best of our knowledge, this study was the first to discover genetic polymorphisms in the PRNP gene in amphibians. Full article

Prion diseases are fatal neurodegenerative disorders caused by the misfolding of the normal cellular prion protein (PrP^C) into its infectious isoform (PrP^Sc). Although prion diseases in humans, sheep, goats, and cattle have been extensively studied, feline spongiform encephalopathy (FSE) remains poorly understood. Genetic factors, particularly polymorphisms in the prion protein gene (PRNP) and prion-like protein gene (PRND), have been linked to prion disease susceptibility in various species. However, no studies have yet investigated the PRND gene in cats with respect to prion diseases. Therefore, we investigated polymorphisms in the feline PRND gene and analyzed their genetic characteristics. We sequenced the coding region of the PRND gene using samples from 210 domestic cats and determined the genotype and allele frequencies of PRND polymorphisms. We identified thirteen novel single nucleotide polymorphisms (SNPs), including six non-synonymous variants and one insertion/deletion (InDel) in the feline PRND gene. Four of the non-synonymous SNPs were predicted to have deleterious effects on the Doppel protein’s structure and function. Notably, the SNP c.97A>G (I33V) showed potential structural clashes, and the others formed additional hydrogen bonds. The LD analysis revealed strong genetic associations between the PRND SNPs and the PRNP InDel, suggesting linkage between these loci in cats. This study identifies novel PRND polymorphisms in domestic cats and provides new insights into the genetic factors underlying feline susceptibility to prion diseases. The strong genetic linkage between PRND and PRNP polymorphisms, coupled with predictions of detrimental effects on Doppel protein structure, suggests that PRND gene variants could influence prion disease progression in cats. These findings provide a foundational framework for future studies on the functional implications of PRND polymorphisms in FSE. To the best of our knowledge, this study is the first report on the genetic characteristics of PRND polymorphisms in cats. Full article

Lvliang black goat (LBG) is an excellent local breed resource in China that is known for its black fur, excellent meat quality, and strong adaptability. Studying the genetic mechanism and germplasm characteristics of LBG can provide theoretical and practical basis for the protection of the genetic resources of this breed and help implement conservation and breeding. In this study, the genetic diversity of the LBG population was evaluated using whole-genome SNP data. It was found that the LBG population had a high genetic diversity and a low degree of inbreeding. According to the clustering results of male goats and the relationship between individuals, the LBG population was divided into 13 families. Then, through population structure analysis, it was found that LBG had a close genetic relationship with the Nanjiang goat and Qinggoda goat populations, and they may have the same ancestors. The LBG population has retained some ancient genetic characteristics and is a special population that integrates local genetic characteristics and foreign gene flow. Through four selection signal analyses, we detected multiple candidate genes related to economic traits (CFL2, SCD, NLRP14, etc.) and adaptability (C4BPA, FUT8, PRNP, etc.) in the LBG population. In addition, in a comparative analysis with three commercial breeds (Saanen goat, Boer goat and Angora goat) we also found multiple genes related to physical characteristics (ERG, NRG3, EDN3, etc.). Finally, we performed functional enrichment analysis on these genes and explored their genetic mechanisms. This study provides important data support for the protection and breeding of LBG and provides a new perspective for enriching the genetic diversity of goat populations. Full article

Prion diseases are neurodegenerative disorders caused by misfolded prion proteins. Although rare, the said diseases are always fatal; they commonly cause death within months of developing clinical symptoms, and their diagnosis is exceptionally difficult pre-mortem. There are no known cures or treatments other than symptomatic care. Given the aggressiveness of prion diseases on onset, therapies after disease onset could be challenging. Prevention to reduce the incidence or to delay the disease onset has been suggested to be a more feasible approach. In this perspective article, we summarize our current understandings of the origin, risk factors, and clinical manifestations of prion diseases. We propose a PCR testing of the blood to identify PRNP gene polymorphisms at codons 129 and 127 in individuals with familial PRNP mutations to assess the risk. We further present the CRISPR/Cas9 gene editing strategy as a perspective preventative approach for these high-risk individuals to induce a polymorphic change at codon 127 of the PRNP gene, granting immunity to prion diseases in selected high-risk individuals, in particular, in individuals with familial PRNP mutations. Full article

Prion disorders are fatal infectious diseases that are caused by a buildup of pathogenic prion protein (PrP^Sc) in susceptible mammals. According to new findings, the shadow of prion protein (Sho) encoded by the shadow of prion protein gene (SPRN) is associated with prion protein (PrP), promoting the progression of prion diseases. Although genetic polymorphisms in SPRN are associated with susceptibility to several prion diseases, genetic polymorphisms in the rabbit SPRN gene have not been investigated in depth. We discovered two novel single nucleotide polymorphisms (SNPs) in the leporine SPRN gene on chromosome 18 and found strong linkage disequilibrium (LD) between them. Additionally, strong LD was not found between the polymorphisms of PRNP and SPRN genes in rabbits. Furthermore, nonsynonymous SNPs that alter the amino acid sequences within the open reading frame (ORF) of SPRN have been observed in prion disease-susceptible animals, but this is the first report in rabbits. As far as we are aware, this study represents the first examination of the genetic features of the rabbit SPRN gene. Full article

Scrapie is a neurodegenerative disease that impacts sheep and goats, characterized by gradual and progressive changes in neurological function. Recent research shows that the scrapie incubation period is significantly influenced by specific variations in amino acids within the prion protein gene (PRNP). The objective of this study was to estimate the national prevalence of caprine PRNP genetic variability at codons 146, 211, and 222 in goat populations across the United States. A total of 3052 blood, ear tissue, and brain tissue samples were collected from goats from 50 states. The participating states were categorized into four Veterinary Service (VS) district regions. The samples underwent DNA extraction, and the PRNP variants corresponding to codons 146, 211, and 222 were amplified and sequenced. The analysis of PRNP variants, when compared to the PRNP reference sequence, revealed seven alleles in twelve genotypes. The homozygous 146NN, 211RR, and 222QQ alleles, which have been linked to an increased risk of scrapie, were found to be the most prevalent among all the goats. The heterozygous 222QK, 211RQ, 146SD, 146ND, and 146NS alleles and the homozygous 222KK, 146SS, and 146DD alleles, known to be associated with reduced scrapie susceptibility and a prolonged incubation period after experimental challenge, were found in 1.098% (222QK), 2.33% (211RQ), 0.58% (146SD), 3.13% (146ND), 20.68% (146NS), 0.005% (222KK), 3.31% (146SS), and 0.67% (146DD) of goats, respectively. The 222QK allele was found most frequently in goats tested from the east (VS District 1, 1.59%) and southwest (VS District 4, 1.08%) regions, whereas the 211RQ allele was found most often in goats tested from the Midwest (VS District 2, 8.03%) and east (VS District 1, 6.53%) regions. The 146NS allele was found most frequently in goats tested from the northwest (VS District 3, 29.02%) and southwest (VS District 4, 20.69%) regions. Our results showed that the prevalence of less susceptible genotypes at PRNP codon 146 may be sufficient to use genetic susceptibility testing in some herds. This may reduce the number of goats removed as part of a herd clean-up plan and may promote the selective breeding goats for less susceptible alleles in high-risk herds at the national level. Full article

Bovine spongiform encephalopathy (BSE) is a fatal disease in cattle caused by misfolded prion proteins and linked to indel polymorphisms in the promoter and intron 1 of the PRNP gene. The aim of this study was to determine the allele, genotype, and haplotype frequencies of PRNP indel polymorphisms and to investigate the effect of PRNP gene expressions of 23 bp and 12 bp indels via polymerase chain reaction (PCR) in Zhongdian Yak (Bos-grunniens) (YK), Zhongdian Yellow cattle (Bos-taurus) (YC), and Zhongdian Yakow (Bos-primigenius taurus × Bos-grunniens) (PK). Resultant high allelic frequencies were found in 23− and 12+, while haplotype frequencies were very low in 23+/12 in YK, YC, and PK. PRNP expression was higher in the +−/−− diplotype of the PK and (mean ± SE) was 3.6578 ± 1.85964. Furthermore, two variable sites were investigated—a 23 bp indel polymorphism holding AP1 binding site and a 12 bp indel polymorphism holding SP1 binding site. Additionally, reporter gene assays revealed a link between two proposed transcription factors and lower expression levels of the +/+ allele compared with the −/− allele. The expression level of PRNP was shown to be dependent on two indel polymorphisms in the bovine PRNP promoter, which includes binding sites for RP58 and SP1 transcription factors. These findings raised the possibility that the PRNP genotype may contribute to the high variation in PRNP expression. Full article

Sporadic Creutzfeldt–Jakob disease (CJD) is a major human prion disease worldwide. CJD is a fatal neurodegenerative disease caused by an abnormal prion protein (PrP^Sc). To date, the exact etiology of sporadic CJD has not been fully elucidated. We investigated the E200K and V203I somatic mutations of the prion protein gene (PRNP) in sporadic CJD patients and matched healthy controls using pyrosequencing. In addition, we estimated the impact of somatic mutations on the human prion protein (PrP) using PolyPhen-2, PANTHER and PROVEAN. Furthermore, we evaluated the 3D structure and electrostatic potential of the human PrP according to somatic mutations using DeepView. The rates of PRNP K200 somatic mutation were significantly increased in the frontal cortex and hippocampus of sporadic CJD patients compared to the matched controls. In addition, the electrostatic potential of the human PrP was significantly changed by the K200 somatic mutation of the PRNP gene. To the best of our knowledge, this is the first report on an association of the PRNP K200 somatic mutation with sporadic CJD. Full article

Scrapie is a fatal, neurodegenerative disease that affects sheep and goats, and genetic susceptibility to scrapie in sheep is associated with polymorphisms in the prion protein (PRNP) gene. The aim of this study is to identify PRNP polymorphism in Awassi sheep from Türkiye, the Palestinian Authority, and Saudi Arabia. A total of 150 healthy sheep were genotyped for PRNP, using Sanger sequencing. There were seven alleles and eleven genotypes observed based on codons 136, 154, and 171 of PRNP. The ARQ allele was predominant in all populations. The most resistant allele to scrapie, ARR, was present in all three regions. The VRQ allele, associated with the highest susceptibility to scrapie, was detected only in Türkiye at a low frequency. In this study, twenty-seven amino acid substitutions were found. Eight of them (R40Q, G65E, H88L, S98T, A118P, S138T, V192F and L250I) have not been previously reported. These data indicate that sheep breeds close to the sheep domestication center have maintained high genetic diversity in the PRNP region. Our findings on PRNP will provide valuable insights for sheep breeding programs, aiding in the selection of genotypes resistant to scrapie in Türkiye, the Palestinian Authority, and Saudi Arabia. Full article

Fatal familial insomnia (FFI) is a rare autosomal-dominant inherited prion disease with a wide variability in age of onset. Its causes are not known. In the present study, we aimed to analyze genetic risk factors other than the prion protein gene (PRNP), in FFI patients with varying ages of onset. Whole-exome sequencing (WES) analysis was performed for twenty-five individuals with FFI (D178N-129M). Gene ontology enrichment analysis was carried out by Reactome to generate hypotheses regarding the biological processes of the identified genes. In the present study, we used a statistical approach tailored to the specifics of the data and identified nineteen potential gene variants with a potential effect on the age of onset. Evidence for potential disease modulatory risk loci was observed in two pseudogenes (NR1H5P, GNA13P1) and three protein coding genes (EXOC1L, SRSF11 and MSANTD3). These genetic variants are absent in FFI patients with early disease onset (19–40 years). The biological function of these genes and PRNP is associated with programmed cell death, caspase-mediated cleavage of cytoskeletal proteins and apoptotic cleavage of cellular proteins. In conclusions, our study provided first evidence for the involvement of genetic risk factors additional to PRNP, which may influence the onset of clinical symptoms in FFI. Full article