Human prion diseases are fatal neurodegenerative disorders that are characterized by spongiform changes, astrogliosis, and the accumulation of an abnormal prion protein (PrP(Sc)). Approximately 10%-15% of human prion diseases are familial variants that are caused by pathogenic mutations in the prion protein gene (PRNP). Point mutations or the insertions of one or more copies of a 24 bp repeat are associated with familial human prion diseases including familial Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker syndrome, and fatal familial insomnia. These mutations vary significantly in frequency between countries. Here, we compare the frequency of PRNP mutations between European countries and East Asians. Associations between single nucleotide polymorphisms (SNPs) of several candidate genes including PRNP and CJD have been reported. The SNP of PRNP at codon 129 has been shown to be associated with sporadic, iatrogenic, and variant CJD. The SNPs of several genes other than PRNP have been showed contradictory results. Case-control studies and genome-wide association studies have also been performed to identify candidate genes correlated with variant and/or sporadic CJD. This review provides a general overview of the genetic mutations and polymorphisms that have been analyzed in association with human prion diseases to date.
Europe ; Far East ; Humans ; Mutation ; Polymorphism, Single Nucleotide ; Prion Diseases/epidemiology/*genetics ; Prions/*genetics

OBJECTIVETo study the conversion of mutant D178N prion protein in RT-QuIC assay.

METHODSThe D178N mutant prion PRNP was generated by the method of single site mutation. The mutant PRNP gene was inserted into plasmids of pET24. The full and N-truncated recombinant human prion proteins were expressed and purified. The fibril formations of these proteins were real-time monitored by the method of RT-QuIC. The ability to resist proteinase K (PK) of these fibrils was analyzed.

RESULTSWe succeed to construct human PrP-D178N plamids. The N-truncated human prion protein with D178N (PrP90-231-D178N) can convert spontaneously in RT-QuIC, while full length of human prion D178N protein (PrP23-231-D178N) fails to convert spontaneously. The spontaneously generated fibril has been domenstrated it is partily PK-resistant.

CONCLUSIONThe N-terminal of prion protein (23-90) plays an important role for the D178N mutant protein spontaneously conversion, which provide the clues for study the pathogenesis of genetic CJD.

Creutzfeldt-Jakob Syndrome ; etiology ; Humans ; Mutant Proteins ; genetics ; Nucleic Acid Amplification Techniques ; methods ; Prions ; genetics

In order to study the physicochemical characteristics of cytosolic PrP (CytoPrP) and evaluate its possible influence on cell viability, a recombinant plasmid expressing human CytoPrP eukaryoticly was constructed and transfected into human neuroblastoma cell line SH-SY5Y transiently. Proteinase-resistant activities of CytoPrP were evaluated by a proteinase K (PK) digestion and cytotoxic effects of CytoPrP were tested by MTT assay and Trypan Blue cell-counting. The presence of CytoPrP in cytoplasm after transfection was controlled by the presence of protease inhibitor. Compared with wild-type PrP, CytoPrP possessed relatively stronger PK-resistant activities. Obvious cytotoxic effects were observed in the cells after inducement of CytoPrP in cytoplasm by protease inhibitor, showing a dose-dependent manner. The results provide useful scientific evidences for further studies of potential role of CytoPrP in pathological mechanism of prion disease.
Cell Line, Tumor ; Cell Survival ; Cytosol ; chemistry ; Endopeptidase K ; pharmacology ; Humans ; Prions ; genetics ; physiology ; Transfection

Bovine spongiform encephalopathy (BSE) is one of the fatal neurodegenerative diseases known as transmissible spongiform encephalopathies (TSEs) caused by infectious prion proteins. Genetic variations correlated with susceptibility or resistance to TSE in humans and sheep have not been reported for bovine strains including those from Holstein, Jersey, and Japanese Black cattle. Here, we investigated bovine prion protein gene (PRNP) variations in Hanwoo cattle [Bos (B.) taurus coreanae], a native breed in Korea. We identified mutations and polymorphisms in the coding region of PRNP, determined their frequency, and evaluated their significance. We identified four synonymous polymorphisms and two non-synonymous mutations in PRNP, but found no novel polymorphisms. The sequence and number of octapeptide repeats were completely conserved, and the haplotype frequency of the coding region was similar to that of other B. taurus strains. When we examined the 23-bp and 12-bp insertion/deletion (indel) polymorphisms in the non-coding region of PRNP, Hanwoo cattle had a lower deletion allele and 23-bp del/12-bp del haplotype frequency than healthy and BSE-affected animals of other strains. Thus, Hanwoo are seemingly less susceptible to BSE than other strains due to the 23-bp and 12-bp indel polymorphisms.
Animals ; Base Sequence ; Cattle ; DNA/genetics ; Encephalopathy, Bovine Spongiform/*genetics ; *Genetic Variation ; Haplotypes ; Prions/*genetics ; Republic of Korea

OBJECTIVETo investigate epidemiological, clinical and genetic features of the first Chinese case of Creutzfeldt-Jakob disease (CJD ) with mutation of E200K in PRNP.

METHODSThe general epidemiological and clinical data were collected; CSF 14-3-3 protein was analyzed by Western blot; The PRNP was amplified by PCR and analyzed.

RESULTSA missense mutation in codon 200 (E200K) of the PRNP was identified in this patient; CSF 14-3-3 protein was positive; sleep disturbance was the initial sign and the other symptoms gradually appeared, including memory loss, dizziness and ataxia.

CONCLUSIONThe CJD patient who was first reported in China has a missense mutation in codon 200 (E200K) of the PRNP, and the codon 129 is a methionine homozygous genotype.

Asian Continental Ancestry Group ; China ; Creutzfeldt-Jakob Syndrome ; genetics ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Prion Proteins ; Prions ; genetics

The polymorphism at codon 129 (M129V) of the human prion protein gene (PRNP) is a known risk factor for Creutzfeldt-Jakob disease (CJD) in Caucasians. There are few reports of this polymorphism's effect on memory and on the risk of Alzheimer's disease (AD). The M129V genotype distributions among Asians are very different from Caucasians. Another polymorphism, codon 219 (E219K) is not found in Caucasians. We investigated two polymorphisms of PRNP, M129V (rs1799990) and E219K (rs1800014) in 297 Korean AD patients and 217 healthy subjects. The analysis of the genotype and allele distributions showed no significant difference between the AD patients and the controls in both polymorphisms (P=0.19 genotype, P=0.51 allele for M129V; P=0.64 genotype, P=0.50 allele for E219K). Also, the PRNP polymorphisms were not significantly associated with AD when the populations were stratified for the presence or absence of apolipoprotein E-e4 (ApoE-epsilon4) allele. These results suggest that the PRNP genetic variants are not associated with the risk for AD in Korean population.
Prions/*genetics ; Polymorphism, Genetic/*genetics ; Male ; Korea/epidemiology ; Humans ; Genotype ; Genetic Predisposition to Disease/genetics ; Female ; Codon/genetics ; Apolipoproteins E/genetics ; Alzheimer Disease/*epidemiology/*genetics ; Alleles ; Aged

OBJECTIVEThe present study was conducted to understand the effects of PrP in different octapeptide repeats on proliferation of HeLa cells.

METHODS AND RESULTSMutant PrPs with octapeptide repeat insertion were transiently expressed in HeLa cells and their results of MTT assay showed stronger cytotoxic effect on the proliferation of cells than wild-type PrP. Annexin V/PI assay also demonstrated that the expression of mutant PrPs was much easier to induce apoptosis than wild-type in HeLa cells. The percentage of both early and late stage apoptosis in mutant groups were significantly higher than that of wild type.

CONCLUSIONThese data suggest that the expression of mutant PrPs associated with familial CJD is much easier to induce apoptosis in cultured cells than expression of wild type PrP.

Apoptosis ; genetics ; physiology ; Blotting, Western ; Cell Proliferation ; Cell Survival ; genetics ; physiology ; Colorimetry ; HeLa Cells ; Humans ; Mutation ; Oligopeptides ; genetics ; Plasmids ; genetics ; Prion Proteins ; Prions ; genetics ; metabolism ; physiology ; Transfection

BACKGROUNDAn amino acid polymorphism for Met to Val has been identified at PrP codon 129 from different human races. In this study,the characteristics of polymorphism of PRNP 129th amino acid in Han and Uighur Chinese have been investigated.

METHODSHuman DNAs were extracted from peripheral lymphocytes and PrP gene fragments were amplified with a specific PCR protocol. The distribution of 129th amino acid in PRNP was determined by a PCR-RFLP and the results were analyzed with software SAS for Windows 6.12.

RESULTSThe frequencies of the allele 129 Met and 129 Val were 97.0% and 3.0% in Han Chinese, whereas 91.4% and 8.6% in Uighur Chinese. The frequency of 129 M/M phenotypes in Han Chinese was significantly higher than that in Uighur Chinese (P=0.0490). Comparing the phenotype distributions of codon 129 of Han Chinese with that of Japanese and Caucasian, there was significant difference with Caucasian (P=0.0005),but there was no difference with Japanese (P=0.5040).

CONCLUSIONSThe polymorphism of 129th amino acid in PRNP of Han Chinese is similar to Japanese, but different from Uighur Chinese.

Asian Continental Ancestry Group ; genetics ; China ; Codon ; genetics ; European Continental Ancestry Group ; genetics ; Gene Frequency ; Genotype ; Humans ; Polymorphism, Genetic ; Prion Diseases ; genetics ; Prions ; genetics

Human genetic prion diseases (gPrDs) are directly associated with mutations and insertions in the PRNP (Prion Protein) gene. We collected and analyzed the data of 218 Chinese gPrD patients identified between Jan 2006 and June 2020. Nineteen different subtypes were identified and gPrDs accounted for 10.9% of all diagnosed PrDs within the same period. Some subtypes of gPrDs showed a degree of geographic association. The age at onset of Chinese gPrDs peaked in the 50-59 year group. Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI) cases usually displayed clinical symptoms earlier than genetic Creutzfeldt-Jakob disease (gCJD) patients with point mutations. A family history was more frequently recalled in P105L GSS and D178N FFI patients than T188K and E200K patients. None of the E196A gCJD patients reported a family history. The gCJD cases with point mutations always developed clinical manifestations typical of sporadic CJD (sCJD). EEG examination was not sensitive for gPrDs. sCJD-associated abnormalities on MRI were found in high proportions of GSS and gCJD patients. CSF 14-3-3 positivity was frequently detected in gCJD patients. Increased CSF tau was found in more than half of FFI and T188K gCJD cases, and an even higher proportion of E196A and E200K gCJD patients. 63.6% of P105L GSS cases showed a positive reaction in cerebrospinal fluid RT-QuIC. GSS and FFI cases had longer durations than most subtypes of gCJD. This is one of the largest studies of gPrDs in East Asians, and the illness profile of Chinese gPrDs is clearly distinct. Extremely high proportions of T188K and E196A occur among Chinese gPrDs; these mutations are rarely reported in Caucasians and Japanese.
14-3-3 Proteins/cerebrospinal fluid* ; China ; Creutzfeldt-Jakob Syndrome/genetics* ; Humans ; Mutation/genetics* ; Prion Diseases/genetics* ; Prion Proteins/genetics* ; Prions/genetics* ; tau Proteins/cerebrospinal fluid*

To study the biological function of the N-glycosylation modification of prion proteins (PrP), various eukaryotic expression vectors for the mutants with N-glycosylation modification of human PrP had been constructed and expressed. With site-direct mutation technique, human PRNP gene was mutated and the obtained mutants were subcloned into eukaryotic expressing plasmid pcDNA3.1 and transiently expressed in Hela cervical adenocarcinoma cell. The expression products of the mutated PrP were identified with Western blotting assay and the PNGase digestion assay. Several mutants with specific glycosylation modification were identified from the expressed products by Western blot, including two mutants with one glycosylation site mutated and one without any mutation at glycosylation sites. The expressed products were digested with PNGase F. The wild type proteins and those with one of glycosylation sites mutated were digested, resulting in their molecular weights reduced, while the molecular weights of products with mutations at both glycosylation sites were not changed. The mutant of wild type human PRNP gene at N-glycosylation modification sites and six modified mutants with mono- or non-N-glycosylation had been obtained successfully in the study. Moreover, the modified PrP with mono- and non-N-glycosylation were able to be expressed transitantly in Hela cells, which could be a useful means for studying prions.
Escherichia coli ; genetics ; metabolism ; Glycation End Products, Advanced ; biosynthesis ; genetics ; Glycosylation ; HeLa Cells ; Humans ; Mutagenesis, Site-Directed ; Mutant Proteins ; biosynthesis ; genetics ; Prions ; biosynthesis ; genetics ; Transfection