Molecular dynamics studies on the buffalo prion protein

Genetic characterization of the prion protein gene in camels (Camelus) with comments on the evolutionary history of prion disease in Cetartiodactyla

Transmissible spongiform encephalopathies (TSEs) are a fatal neurogenerative disease that include Creutzfeldt-Jakob disease in humans, scrapie in sheep and goats, bovine spongiform encephalopathy (BSE), and several others as well as the recently described camel prion disease (CPD). CPD originally was documented in 3.1% of camels examined during an antemortem slaughterhouse inspection in the Ouargla region of Algeria. Of three individuals confirmed for CPD, two were sequenced for the exon 3 of the prion protein gene (PRNP) and were identical to sequences previously reported for Camelus dromedarius. Given that other TSEs, such as BSE, are known to be capable of cross-species transmission and that there is household consumption of meat and milk from Camelus, regulations to ensure camel and human health should be a One Health priority in exporting countries. Although the interspecies transmissibility of CPD currently is unknown, genotypic characterization of Camelus PRNP may be used for predictability of predisposition and potential susceptibility to CPD. Herein, eight breeds of dromedary camels from a previous genetic (mitochondrial DNA and microsatellites) and morphological study were genotyped for PRNP and compared to genotypes from CPD-positive Algerian camels. Sequence data from PRNP indicated that Ethiopian camels possessed 100% sequence identity to CPD-positive camels from Algeria. In addition, the camel PRNP genotype is unique compared to other members of the Orders Cetartiodactyla and Perissodactyla and provides an in-depth phylogenetic analysis of families within Cetartiodactyla and Perissodactyla that was used to infer the evolutionary history of the PRNP gene.

Mutations in Prion Protein Gene: Pathogenic Mechanisms in C-Terminal vs. N-Terminal Domain, a Review

Inherited mutations in the Prion protein (PrP), encoded by the PRNP gene, have been associated with autosomal dominant neurodegenerative disorders, such as Creutzfeldt-Jacob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and Fatal Familial Insomnia (FFI). Notably, PRNP mutations have also been described in clinical pictures resembling other neurodegenerative diseases, such as frontotemporal dementia. Regarding the pathogenesis, it has been observed that these point mutations are located in the C-terminal region of the PRNP gene and, currently, the potential significance of the N-terminal domain has largely been underestimated. The purpose of this report is to review and provide current insights into the pathogenic mechanisms of PRNP mutations, emphasizing the differences between the C- and N-terminal regions and focusing, in particular, on the lesser-known flexible N-terminal, for which recent biophysical evidence has revealed a physical interaction with the globular C-terminal domain of the cellular prion protein (PrPC).

Nucleotide and octapeptide-repeat variations of the prion protein coding gene (PRNP) in Anatolian, Murrah, and crossbred water buffaloes

Resistance to bovine spongiform encephalopathy (BSE) that is significantly associated with insertion/deletion (indel) polymorphisms at two loci (putative promoter and intron 1) on the prion protein gene (PRNP) in cattle has been well documented. Studies suggest that the insertion alleles are related to BSE resistance. Until recently, BSE has never been reported in water buffaloes (unlike cattle). Previous studies have demonstrated that the PRNP gene in water buffalo consists mostly of insertion alleles at both loci; nevertheless, whether or not water buffaloes are genetically resistant to BSE and the role of indel polymorphisms in their resistance status is not clear. We examined the coding region of PRNP to determine the nucleotide and octapeptide-repeat (octarepeats) variations of Anatolian, Murrah and Murrah × Anatolian (M × A) water buffaloes. Three synonymous single nucleotide polymorphisms (SNP) at positions 126, 234, and 285, and a non-synonymous SNP at position 322 (G108S) were detected. Triplet G/A/T base substitutions were observed at position 126 and two additional genotypes, T/A and T/G, at this position were determined. We also found six octarepeats that indicated the presence of the wild-type PRNP6 allele in the coding region. To the best of our knowledge, this is the first report of the T/A and T/G genotypes in water buffaloes.