Transmissible Spongiform Encephalopathy Diseases Research Articles

Prion Protein Octarepeat Domain Forms Transient β-Sheet Structures upon Residue-Specific Binding to Cu(II) and Zn(II) Ions.

Misfolding of the cellular prion protein (PrPC) is associated with the development of fatal neurodegenerative diseases called transmissible spongiform encephalopathies (TSEs). Metal ions appear to play a crucial role in PrPC misfolding. PrPC is a combined Cu(II) and Zn(II) metal-binding protein, where the main metal-binding site is located in the octarepeat (OR) region. Thus, the biological function of PrPC may involve the transport of divalent metal ions across membranes or buffering concentrations of divalent metal ions in the synaptic cleft. Recent studies have shown that an excess of Cu(II) ions can result in PrPC instability, oligomerization, and/or neuroinflammation. Here, we have used biophysical methods to characterize Cu(II) and Zn(II) binding to the isolated OR region of PrPC. Circular dichroism (CD) spectroscopy data suggest that the OR domain binds up to four Cu(II) ions or two Zn(II) ions. Binding of the first metal ion results in a structural transition from the polyproline II helix to the β-turn structure, while the binding of additional metal ions induces the formation of β-sheet structures. Fluorescence spectroscopy data indicate that the OR region can bind both Cu(II) and Zn(II) ions at neutral pH, but under acidic conditions, it binds only Cu(II) ions. Molecular dynamics simulations suggest that binding of either metal ion to the OR region results in the formation of β-hairpin structures. As the formation of β-sheet structures can be a first step toward amyloid formation, we propose that high concentrations of either Cu(II) or Zn(II) ions may have a pro-amyloid effect in TSE diseases.

Defining the Protein Seeds of Neurodegeneration using Real-Time Quaking-Induced Conversion Assays.

Neurodegenerative diseases are characterized by the accumulation of disease-related misfolded proteins. It is now widely understood that the characteristic self-amplifying (i.e., seeding) capacity once only attributed to the prions of transmissible spongiform encephalopathy diseases is a feature of other misfolded proteins of neurodegenerative diseases, including tau, Aβ, and αSynuclein (αSyn). Ultrasensitive diagnostic assays, known as real-time quaking-induced conversion (RT-QuIC) assays, exploit these seeding capabilities in order to exponentially amplify protein seeds from various biospecimens. To date, RT-QuIC assays have been developed for the detection of protein seeds related to known prion diseases of mammals, the αSyn aggregates of Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy, and the tau aggregates of Alzheimer’s disease, chronic traumatic encephalopathy, and other tauopathies including progressive supranuclear palsy. Application of these assays to premortem human biospecimens shows promise for diagnosis of neurodegenerative disease and is an area of active investigation. RT-QuIC assays are also powerful experimental tools that can be used to dissect seeding networks within and between tissues and to evaluate how protein seed distribution and quantity correlate to disease-related outcomes in a host. As well, RT-QuIC application may help characterize molecular pathways influencing protein seed accumulation, transmission, and clearance. In this review we discuss the application of RT-QuIC assays as diagnostic, experimental, and structural tools for detection and discrimination of PrP prions, tau, and αSyn protein seeds.

Creutzfeldt-Jakob Disease: An Overview

Creutzfeldt-Jakob disease (CJD) belongs to a family of fatal degenerative disorders of the nervous system known as transmissible spongiform encephalopathy (TSE) or prion diseases, which affect both animals and humans. It is characterized by neuronal loss or neuronal degeneration, spongiform change and astrocyticgliosis which finally results in fatal neurological disorder. CJD affects one million people worldwide each year. The clinical presentation of CJD includes rapidly developing dementia, neurological symptoms, visual impairment, ataxia and development of akinetic mutism and eventually death. The diagnosis is based on clinical presentation and is diagnosed by Magnetic resonance imaging (MRI) findings, electroencephalogram (EEG), cerebrospinal fluid tests (CSF) and genetic tests such as PRNP gene. There have been recent advances in diagnostic techniques, which have allowed more accurate case recognition in all forms of the CJD. The mainstay of treatment is symptomatic and supportive. There have been many medical advances towards a cure for CJD but no definitive drug or therapy has been identified for the disease.

Infectious Prions in the Pregnancy Microenvironment of Chronic Wasting Disease-Infected Reeves' Muntjac Deer.

Ample evidence exists for the presence of infectious agents at the maternal-fetal interface, often with grave outcomes to the developing fetus (i.e., Zika virus, brucella, cytomegalovirus, and toxoplasma). While less studied, pregnancy-related transmissible spongiform encephalopathies (TSEs) have been implicated in several species, including humans. Our previous work has shown that prions can be transferred from mother to offspring, resulting in the development of clinical TSE disease in offspring born to muntjac dams infected with chronic wasting disease (CWD) (1). We further demonstrated protein misfolding cyclic amplification (PMCA)-competent prions within the female reproductive tract and in fetal tissues harvested from CWD experimentally and naturally exposed cervids (1, 2). To assess whether the PMCA-competent prions residing at the maternal-fetal interface were infectious and to determine if the real-time quaking-induced conversion (RT-QuIC) methodology may enhance our ability to detect amyloid fibrils within the pregnancy microenvironment, we employed a mouse bioassay and RT-QuIC. In this study, we have demonstrated RT-QuIC seeding activity in uterus, placentome, ovary, and amniotic fluid but not in allantoic fluids harvested from CWD-infected Reeves' muntjac dams showing clinical signs of infection (clinically CWD-infected) and in some placentomes from pre-clinically CWD-infected dams. Prion infectivity was confirmed within the uterus, amniotic fluid, and the placentome, the semipermeable interface that sustains the developing fetus, of CWD-infected dams. This is the first report of prion infectivity within the cervid pregnancy microenvironment, revealing a source of fetal CWD exposure prior to the birthing process, maternal grooming, or encounters with contaminated environments.IMPORTANCE The facile dissemination of chronic wasting disease within captive and free-range cervid populations has led to questions regarding the transmission dynamics of this disease. Direct contact with infected animals and indirect contact with infectious prions in bodily fluids and contaminated environments are suspected to explain the majority of this transmission. A third mode of transmission, from mother to offspring, may be underappreciated. The presence of pregnancy-related prion infectivity within the uterus, amniotic fluid, and the placental structure reveals that the developing fetus is exposed to a source of prions long before exposure to the infectious agent during and after the birthing process or via contact with contaminated environments. These findings have impact on our current concept of CWD disease transmission.

Pathology of Animal Transmissible Spongiform Encephalopathies (TSEs).

Pathology is the study of the structural and functional changes produced by diseases or - more specifically - the lesions they cause. To achieve this pathologists employ various approaches. These include description of lesions that are visible to the naked eye which are the subject of anatomic pathology and changes at the cellular level that are visible under the microscope, the subject of histopathology. Changes at the molecular level which are identified by probes that target specific molecules - mainly proteins that are detected using immunohistochemistry (IHC). As transmissible spongiform encephalopathies (TSEs) do not cause visible lesions anatomic pathology is not applicable to their study. For decades the application of histopathology to detect vacuoles or plaques was the only means of confirming TSE disease. The subsequent discovery of the cellular prion protein (PrPC) and its pathogenic isoform, PrPSc, which is a ubiquitous marker of TSEs, led to the production of anti-PrP antibodies, and enabled the development of PrPSc detection techniques such as immunohistochemistry, Histoblot and PET-blot that have evolved in parallel with similar biochemical methods such as Western blot and ELISA. These methods offer greater sensitivity than histopathology in TSE diagnosis and crucially they can be applied to analyze various phenotypic aspects of single TSE sources increasing the amount of data and offering higher discriminatory power. The above principles are applied to diagnose and define TSE phenotypes which form the basis of strain characterisation.

The prion protein selectively binds to and modulates the content of purinergic receptor P2X4R

The GPI-anchored prion protein (PrPC) is involved in neurodegeneration, either through misfolding in the Transmissible Spongiform Encephalopathies (TSE), or as a mediator of the neurotoxicity of peptide oligomers in Alzheimer's Disease. PrPC has been attributed pleiotropic functions, and appears to scaffold a variety of cell surface signaling modules, for example through its binding to several neurotransmitter receptors. Here we used transfected HEK293 cells to test for an interaction of PrPC with purinergic receptor P2X4R. The prion protein bound P2X4R in both overlay and co-immunoprecipitation assays, and co-localized mostly intracellularly, but occasionaly at the cell surface in confocal micrographs. Functional PrPC:P2X4R interaction was tested by the uptake of a P2X4R-permeant compound, and by modulation of intracellular calcium. Unexpectedly, however, this interaction was traced to a selective effect of PrPC upon the content of co-transfected P2X4R. The results suggest a role of PrPC in proteostasis, dysfunctions of which may be involved in the pathogenesis of neurodegenerative diseases such as TSE and Alzheimer's Disease.

Assessing Mother to Offspring Transmission of Chronic Wasting Disease Using Transgenic Mouse Models

Chronic wasting disease (CWD) is the transmissible spongiform encephalopathy (TSE), or prion disease, of free-ranging and captive cervids (deer, elk and moose). The presence of sufficient infectious prions in the tissues, bodily fluids (urine, saliva, and blood) and environments of clinical and preclinical CWD-infected animals is thought to account for its high transmission efficiency. Recently it has been recognized that transmission from mother to offspring may contribute to the facile transmission of some TSEs. Although the mechanism of maternal transmission has yet to be elucidated, the extended asymptomatic TSE carrier phase, lasting years to decades, suggests that maternal transmission may have implications in the spread of prions. Placental trafficking and/or secretion in milk are two means by which maternal prion transmission may occur. In these studies we explore CWD maternal transmission during early and late CWD infection using a transgenic mouse model (TgCerPRP) expressing cervid prion protein. Naive and CWD-infected dams were bred during early (45 dpi) and late (120 dpi) infection and were allowed to bear and raise their offspring. Milk was collected from the dams for prion analysis, and the offspring were observed for TSE disease progression. Terminal tissues harvested from these dams and offspring were analyzed for prions. We have demonstrated: 1) that CWD-infected TgCerPRP females successfully breed and bear offspring, 2) the presence of PrP CWD in reproductive and mammary tissue harvested from CWD-infected dams, and 3) clinical disease progression in offspring born to CWD-infected dams. We are currently analyzing terminal tissue harvested from offspring born to CWD-infected dams for the detection of PrP CWD and amplification competent prions. These studies will provide insight into the potential mechanisms and biological significance associated with mother to offspring transmission of TSEs.

Transcriptome analysis of CNS immediately before and after the detection of PrPSc in SSBP/1 sheep scrapie

Sheep scrapie is a transmissible spongiform encephalopathy (TSE), progressive and fatal neurodegenerative diseases of the central nervous system (CNS) linked to the accumulation of misfolded prion protein, PrPSc. New Zealand Cheviot sheep, homozygous for the VRQ genotype of the PRNP gene are most susceptible with an incubation period of 193 days with SSBP/1 scrapie. However, the earliest time point that PrPSc can be detected in the CNS is 125 days (D125). The aim of this study was to quantify changes to the transcriptome of the thalamus and obex (medulla) at times immediately before (D75) and after (D125) PrPSc was detected. Affymetrix gene arrays were used to quantify gene expression in the thalamus and Illumina DGE-tag profiling for obex. Ingenuity Pathway Analysis was used to help describe the biological processes of scrapie pathology.Neurological disease and Cancer were common Bio Functions in each tissue at D75; inflammation and cell death were major processes at D125. Several neurological receptors were significantly increased at D75 (e.g. CHRNA6, GRM1, HCN2), which might be clues to the molecular basis of psychiatric changes associated with TSEs. No genes were significantly differentially expressed at both D75 and D125 and there was no progression of events from earlier to later time points. This implies that there is no simple linear progression of pathological or molecular events. There seems to be a step-change between D75 and D125, correlating with the detection of PrPSc, resulting in the involvement of different pathological processes in later TSE disease.

Glycosylphosphatidylinositol Anchoring Directs the Assembly of Sup35NM Protein into Non-fibrillar, Membrane-bound Aggregates

In prion-infected hosts, PrPSc usually accumulates as non-fibrillar, membrane-bound aggregates. Glycosylphosphatidylinositol (GPI) anchor-directed membrane association appears to be an important factor controlling the biophysical properties of PrPSc aggregates. To determine whether GPI anchoring can similarly modulate the assembly of other amyloid-forming proteins, neuronal cell lines were generated that expressed a GPI-anchored form of a model amyloidogenic protein, the NM domain of the yeast prion protein Sup35 (Sup35(GPI)). We recently reported that GPI anchoring facilitated the induction of Sup35(GPI) prions in this system. Here, we report the ultrastructural characterization of self-propagating Sup35(GPI) aggregates of either spontaneous or induced origin. Like membrane-bound PrPSc, Sup35(GPI) aggregates resisted release from cells treated with phosphatidylinositol-specific phospholipase C. Sup35(GPI) aggregates of spontaneous origin were detergent-insoluble, protease-resistant, and self-propagating, in a manner similar to that reported for recombinant Sup35NM amyloid fibrils and induced Sup35(GPI) aggregates. However, GPI-anchored Sup35 aggregates were not stained with amyloid-binding dyes, such as Thioflavin T. This was consistent with ultrastructural analyses, which showed that the aggregates corresponded to dense cell surface accumulations of membrane vesicle-like structures and were not fibrillar. Together, these results showed that GPI anchoring directs the assembly of Sup35NM into non-fibrillar, membrane-bound aggregates that resemble PrPSc, raising the possibility that GPI anchor-dependent modulation of protein aggregation might occur with other amyloidogenic proteins. This may contribute to differences in pathogenesis and pathology between prion diseases, which uniquely involve aggregation of a GPI-anchored protein, versus other protein misfolding diseases.

Procedures for Identifying Infectious Prions After Passage Through the Digestive System of an Avian Species

Infectious prion (PrP(Res)) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases(1). Transmission of TSE diseases, such as chronic wasting disease (CWD), is presumed to be from animal to animal(2,3) as well as from environmental sources(4-6). Scavengers and carnivores have potential to translocate PrP(Res) material through consumption and excretion of CWD-contaminated carrion. Recent work has documented passage of PrP(Res) material through the digestive system of American crows (Corvus brachyrhynchos), a common North American scavenger(7). We describe procedures used to document passage of PrP(Res) material through American crows. Crows were gavaged with RML-strain mouse-adapted scrapie and their feces were collected 4 hr post gavage. Crow feces were then pooled and injected intraperitoneally into C57BL/6 mice. Mice were monitored daily until they expressed clinical signs of mouse scrapie and were thereafter euthanized. Asymptomatic mice were monitored until 365 days post inoculation. Western blot analysis was conducted to confirm disease status. Results revealed that prions remain infectious after traveling through the digestive system of crows and are present in the feces, causing disease in test mice.

Metabolism of minor isoforms of prion proteins: Cytosolic prion protein and transmembrane prion protein.

Transmissible spongiform encephalopathy or prion disease is triggered by the conversion from cellular prion protein to pathogenic prion protein. Growing evidence has concentrated on prion protein configuration changes and their correlation with prion disease transmissibility and pathogenicity. In vivo and in vitro studies have shown that several cytosolic forms of prion protein with specific topological structure can destroy intracellular stability and contribute to prion protein pathogenicity. In this study, the latest molecular chaperone system associated with endoplasmic reticulum-associated protein degradation, the endoplasmic reticulum resident protein quality-control system and the ubiquitination proteasome system, is outlined. The molecular chaperone system directly correlates with the prion protein degradation pathway. Understanding the molecular mechanisms will help provide a fascinating avenue for further investigations on prion disease treatment and prion protein-induced neurodegenerative diseases.

Presence of subclinical infection in gene-targeted human prion protein transgenic mice exposed to atypical bovine spongiform encephalopathy

The transmission of bovine spongiform encephalopathy (BSE) to humans, leading to variant Creutzfeldt-Jakob disease has demonstrated that cattle transmissible spongiform encephalopathies (TSEs) can pose a risk to human health. Until recently, TSE disease in cattle was thought to be caused by a single agent strain, BSE, also known as classical BSE, or BSE-C. However, due to the initiation of a large-scale surveillance programme throughout Europe, two atypical BSE strains, bovine amyloidotic spongiform encephalopathy (BASE, also named BSE-L) and BSE-H have since been discovered. To model the risk to human health, we previously inoculated these two forms of atypical BSE (BASE and BSE-H) into gene-targeted transgenic (Tg) mice expressing the human prion protein (PrP) (HuTg) but were unable to detect any signs of TSE pathology in these mice. However, despite the absence of TSE pathology, upon subpassage of some BASE-challenged HuTg mice, a TSE was observed in recipient gene-targeted bovine PrP Tg (Bov6) mice but not in HuTg mice. Disease transmission from apparently healthy individuals indicates the presence of subclinical BASE infection in mice expressing human PrP that cannot be identified by current diagnostic methods. However, due to the lack of transmission to HuTg mice on subpassage, the efficiency of mouse-to-mouse transmission of BASE appears to be low when mice express human rather than bovine PrP.

Thermodynamic Stabilization of the Folded Domain of Prion Protein Inhibits Prion Infection in Vivo

Prion diseases, or transmissible spongiform encephalopathies (TSEs), are associated with the conformational conversion of the cellular prion protein, PrP(C), into a protease-resistant form, PrP(Sc). Here, we show that mutation-induced thermodynamic stabilization of the folded, α-helical domain of PrP(C) has a dramatic inhibitory effect on the conformational conversion of prion protein invitro, as well as on the propagation of TSE disease invivo. Transgenic mice expressing a human prion protein variant with increased thermodynamic stability were found to be much more resistant to infection with the TSE agent than those expressing wild-type human prion protein, in both the primary passage and three subsequent subpassages. These findings not only provide a line of evidence in support of the protein-only model of TSEs but also yield insight into the molecular nature of the PrP(C)→PrP(Sc) conformational transition, and they suggest an approach to the treatment of prion diseases.

Dissociation between Transmissible Spongiform Encephalopathy (TSE) Infectivity and Proteinase K-Resistant PrP Sc Levels in Peripheral Tissue from a Murine Transgenic Model of TSE Disease

Most current diagnostic tests for transmissible spongiform encephalopathies (TSE) rely on the presence of proteinase K (PK)-resistant PrP(Sc) (PrP-res) in postmortem tissues as an indication of TSE disease. However, a number of studies have highlighted a discrepancy between TSE infectivity and PrP-res levels in both natural and experimental cases of TSE disease. Previously, we have shown high TSE infectivity levels in the brain tissue of mice that have a clinical TSE disease with associated vacuolar pathology but little or no detectable PrP-res. Here, the levels of TSE infectivity and PrP-res within a peripheral tissue of this mouse model were investigated. Biochemical analysis showed that low levels of PrP-res were present in the spleen tissue in comparison to the levels observed in the spleen of mice infected with ME7 or 79A. However, upon subpassage of brain and spleen tissue from clinically ill mice with little or no PrP-res detectable, similar short incubation periods to disease were observed, indicating that infectivity levels were similarly high in both tissues. Thus, the discrepancy between PrP-res and TSE infectivity was also present in the peripheral tissues of this disease model. This result indicates that peripheral tissues can contain higher levels of infectivity given the correct combination of host species, PrP genotype, and TSE agent. Therefore, the assumption that the levels of peripheral infectivity are lower than those in the central nervous system is not always correct, and this could have implications for current food safety regulations.

Fluorescence Spectroscopy of the Retina from Scrapie‐Infected Mice

Recently, we have proposed that the fluorescence spectra of sheep retina can be well correlated with the presence or absence of scrapie. Scrapie is the most widespread TSE (transmissible spongiform encephalopathy) affecting sheep and goats worldwide. Mice eyes have been previously reported as a model system to study age-related accumulation of lipofuscin, which has been investigated by monitoring the increasing fluorescence with age covering its entire life span. The current work aims at developing mice retina as a convenient model system to diagnose scrapie and other fatal TSE diseases in animals such as sheep and cows. The objective of the research reported here was to determine whether the spectral features are conserved between two different species namely mice and sheep, and whether an appropriate small animal model system could be identified for diagnosis of scrapie based on the fluorescence intensity in retina. The results were consistent with the previous reports on fluorescence studies of healthy and scrapie-infected retina of sheep. The fluorescence from the retinas of scrapie-infected sheep was significantly more intense and showed more heterogeneity than that from the retinas of uninfected mice. Although the structural characteristics of fluorescence spectra of scrapie-infected sheep and mice eyes are slightly different, more importantly, murine retinas reflect the enhancement of fluorescence intensity upon infecting the mice with scrapie, which is consistent with the observations in sheep eyes.

Identification of Misfolded Proteins in Body Fluids for the Diagnosis of Prion Diseases

Transmissible spongiform encephalopathy (TSE) or prion diseases are fatal rare neurodegenerative disorders affecting man and animals and caused by a transmissible infectious agent. TSE diseases are characterized by spongiform brain lesions with neuronal loss and the abnormal deposition in the CNS, and to less extent in other tissues, of an insoluble and protease resistant form of the cellular prion protein (PrPC), named PrPTSE. In man, TSE diseases affect usually people over 60 years of age with no evident disease-associated risk factors. In some cases, however, TSE diseases are unequivocally linked to infectious episodes related to the use of prion-contaminated medicines, medical devices, or meat products as in the variant Creutzfeldt-Jakob disease (CJD). Clinical signs occur months or years after infection, and during this silent period PrPTSE, the only reliable marker of infection, is not easily measurable in blood or other accessible tissues or body fluids causing public health concerns. To overcome the limit of PrPTSE detection, several highly sensitive assays have been developed, but attempts to apply these techniques to blood of infected hosts have been unsuccessful or not yet validated. An update on the latest advances for the detection of misfolded prion protein in body fluids is provided.

Prion Remains Infectious after Passage through Digestive System of American Crows (Corvus brachyrhynchos)

Avian scavengers, such as American crows (Corvus brachyrhynchos), have potential to translocate infectious agents (prions) of transmissible spongiform encephalopathy (TSE) diseases including chronic wasting disease, scrapie, and bovine spongiform encephalopathy. We inoculated mice with fecal extracts obtained from 20 American crows that were force-fed material infected with RML-strain scrapie prions. These mice all evinced severe neurological dysfunction 196–231 d postinoculation ( = 198; 95% CI: 210–216) and tested positive for prion disease. Our results suggest a large proportion of crows that consume prion-positive tissue are capable of passing infectious prions in their feces ( = 1.0; 95% CI: 0.8–1.0). Therefore, this common, migratory North American scavenger could play a role in the geographic spread of TSE diseases.

Isolation of Novel Synthetic Prion Strains by Amplification in Transgenic Mice Coexpressing Wild-Type and Anchorless Prion Proteins

Mammalian prions are thought to consist of misfolded aggregates (protease-resistant isoform of the prion protein [PrP(res)]) of the cellular prion protein (PrP(C)). Transmissible spongiform encephalopathy (TSE) can be induced in animals inoculated with recombinant PrP (rPrP) amyloid fibrils lacking mammalian posttranslational modifications, but this induction is inefficient in hamsters or transgenic mice overexpressing glycosylphosphatidylinositol (GPI)-anchored PrP(C). Here we show that TSE can be initiated by inoculation of misfolded rPrP into mice that express wild-type (wt) levels of PrP(C) and that synthetic prion strain propagation and selection can be affected by GPI anchoring of the host's PrP(C). To create prions de novo, we fibrillized mouse rPrP in the absence of molecular cofactors, generating fibrils with a PrP(res)-like protease-resistant banding profile. These fibrils induced the formation of PrP(res) deposits in transgenic mice coexpressing wt and GPI-anchorless PrP(C) (wt/GPI(-)) at a combined level comparable to that of PrP(C) expression in wt mice. Secondary passage into mice expressing wt, GPI(-), or wt plus GPI(-) PrP(C) induced TSE disease with novel clinical, histopathological, and biochemical phenotypes. Contrary to laboratory-adapted mouse scrapie strains, the synthetic prion agents exhibited a preference for conversion of GPI(-) PrP(C) and, in one case, caused disease only in GPI(-) mice. Our data show that novel TSE agents can be generated de novo solely from purified mouse rPrP after amplification in mice coexpressing normal levels of wt and anchorless PrP(C). These observations provide insight into the minimal elements required to create prions in vitro and suggest that the PrP(C) GPI anchor can modulate the propagation of synthetic TSE strains.

Short Communication: The double deletion diplotype showed low levels of prion protein at two indel loci ofPRNPin the medulla oblongata of Japanese Brown cattle

Msalya, G., Shimogiri, T., Okamoto, S., Kawabe, K. and Maeda, Y. 2012. Short Communication: The double deletion diplotype showed low levels of prion protein at two indel loci of PRNP in the medulla oblongata of Japanese Brown cattle. Can. J. Anim. Sci. 92: 153–157. Transmissible spongiform encephalopathies (TSEs) are a class of fatal neurodegenerative diseases caused by abnormally folded prion proteins (PrP). The PrP is necessary for the transmission and propagation of TSE diseases. In this study, PrP was quantified in the medulla oblongata of 39 Japanese Brown (JBr) animals that were genotyped for two indels in the PRNP gene – a 23 bp deletion in the promoter region and a 12 bp deletion in the first intron. The mean level of PrP was greater in the ++/++ diplotype than in −−/−− and +−/+− diplotypes, although the differences were not significant. These results suggest that the amount of PrP in the medulla oblongata of animals is related to these indels. However, given that there have been no reported cases of BSE in Japanese Brown animals, the relationship of the indels and PrP levels with the incidence of BSE is unclear.

SHORT COMMUNICATION: The double deletion diplotype showed low levels of prion protein at two indel loci of PRNP in the medulla oblongata of Japanese Brown cattle

Msalya, G., Shimogiri, T., Okamoto, S., Kawabe, K. and Maeda, Y. 2012. Short Communication: The double deletion diplotype showed low levels of prion protein at two indel loci of PRNP in the medulla oblongata of Japanese Brown cattle. Can. J. Anim. Sci. 92: 153-157. Transmissible spongiform encephalopathies (TSEs) are a class of fatal neurodegenerative diseases caused by abnormally folded prion proteins (PrP). The PrP is necessary for the transmission and propagation of TSE diseases. In this study, PrP was quantified in the medulla oblongata of 39 Japanese Brown (JBr) animals that were genotyped for two indels in the PRNP gene - a 23 bp deletion in the promoter region and a 12 bp deletion in the first intron. The mean level of PrP was greater in the ++/++ diplotype than in --/-- and +-/+- diplotypes, although the differences were not significant. These results suggest that the amount of PrP in the medulla oblongata of animals is related to these indels. However, given that there have been no reported cases...