Mutations in various functional domains of HPV2 E2 protein inhibit the transcriptional depression activities / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the potential transcriptional depression activities of HPV2 E2 proteins with mutations in different functional domains.</p><p><b>METHODS</b>The primers for constructing various E2 mutants were synthesized based on a HPV2 isolate containing several point mutations within E2 open reading frame. Different E2 mutations were generated by the method of extending PCR and inserted into plasmid pcDNA3. 1. Various recombinant mammalian expression plasmids pcDNA3. 1-E2 were co-transfected into HeLa cells together with a CAT-reporter plasmid pBLCAT-LCR containing HPV-2 prototype LCR, respectively. The transcriptional repression activities of the E2 mutants were evaluated by detection of CAT expression values.</p><p><b>RESULTS</b>Compared with the full-length prototype E2, removals of both N- and C-terminal domains abolished E2 transcriptional repressive activities. The point mutations in the transactivation domain (nt 3037), the internal hinge region (nt 3387) and DNA binding domain (nt 3697) showed remarkable inhibition on its transcriptional depression function.</p><p><b>CONCLUSION</b>The transcriptional regulation activity of HPV2 E2 is related with its DNA binding and transactivation domains. The exchanges of the single amino acid within E2, derived from a HPV2 isolate, abolish significantly the repressive effect on viral promoter in the context of full-length E2.</p>

Expressions of nucleoside diphosphate kinase (nm23) in tumor tissues are related with metastasis and length of survival of patients with hepatocellular carcinoma / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To evaluate the relationship of expressions of nucleoside diphosphate kinase (nm23) and proliferating cell nuclear antigen (PCNA), as well as apoptosis, with the prognosis of HCC patients by analyzing their pathological and clinical data.</p><p><b>METHODS</b>The expressions of nm23 and PCNA were analyzed by immunohistochemistry and the apoptotic phenomena were detected by TUNEL technique in the liver samples from 43 HCC tissues, 39 para-neoplastic tissues, and 10 normal tissues. The mean apoptosis index (AI) and proliferative index (PI) in individual sample were calculated.</p><p><b>RESULTS</b>As shown by the detection, 32.6% of carcinomas had negative nm23 signal in tumor tissues, whereas all para-neoplastic and normal tissues had positive nm23. The AI in nm23 positive HCC was significantly higher than that in nm23 negative one, with statistical difference (P<0.05). Furthermore, the expressions of nm23, and the values of AI and PI were contrastively analyzed with some main pathological and clinical data of HCC. It revealed that HCC with extrahepatic metastasis showed remarkable correlation with the negative nm23 (P=0.013) and higher PI values of HCC (P=0.015). The disease-free survival in HCC patients with negative nm23 expression was significantly poorer than that in patients with positive nm23 expression.</p><p><b>CONCLUSIONS</b>These data suggest that expressions of nm23 protein in tumor tissues are correlated with occurrences of metastasis and length of survival of the HCC patients, which may be an indicator for their prognosis.</p>

Studies on heredity rule of the first genealogy regarding fatal familial insomnia in Henan province / 中华流行病学杂志

Objective To investigate the epidemiological,genealogic characteristic,familial history of the families with fatal familial insomnia,its clinical and pathological features as well as the heredity rule of related genes.Methods 135 familial members of 7 eras were studied.Vein blood samples from patients as well as from some familial members were collected.PRNP gene was studied with PCR,its serial was determined and then authenticated with Nsp I.Brain tissue was obtained for neuropathological test and PrPSc test with Western blot method.Results Clinical symptoms of the 2 diagnosed cases were typical.11 familial members died of similar neural disease.32 samples of their familial members,codon at D178N of PRNP of 11 members was mutated,with mutation rate as 34.38% while D129N showed as methionine.Brain tissue of both probands denaturalized into spongiform and the nerve fiber was absent but PrPSc protein was identified.Conclusion Genealogy was described in the family with fatal familial insomnia since the patients had typical clinical symptoms and pathological characteristics.It seemed necessary to confirm cases of fatal familial insomnia and their genealogy with epidemiological data and to investigate its gene characteristics as well as with neuropathological and Western blot tests.

Molecular epidemiological study on prevalence of human papillomaviruses in patients with common warts in Beijing area / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the circulation, distribution, and genomic diversity of HPVs in common warts in Beijing area of China.</p><p><b>METHODS</b>Forty eight patients with pathologically diagnosed common warts were screened for the presence of HPV with HPV type-specific PCR and direct sequencing analysis. The genomic diversity of HPVs prevalent in Chinese patients was analyzed based on LCR.</p><p><b>RESULTS</b>Forty one (85.5%) samples were positive for HPV DNA, 13 (31.7%)--HPV-57, 12 (29.3%)--HPV-1a, 7 (17%)--HPV-27 and 5(12.2%)--HPV-2a. Four cases were infected with two different HPV types, two (4.9%) with HPV-1a and HPV-27, one (2.4%) with HPV-1 and HPV-57 and one (2.4%) with HPV-27 and HPV-57. In contrast to the prevalence of single strain of novel HPV-57 variant and HPV-1 prototype, two HPV-2 and three HPV-27 novel variants were found to circulate in Beijing.</p><p><b>CONCLUSION</b>HPV-1, -2, -27 and -57 are predominantly prevalent in patients with common warts in Beijing.</p>

Establishment of an assay for PrP(Sc) detection based on streptomycin precipitation / 病毒学报

To establish a new Western blotting assay for PrP(Sc) detection, we optimized the Western blotting assay with a precipitation procedure of streptomycin sulfate. After digestion with PK, 10% scrapie infected hamster brain homogenates were incubated with 60 mmol/L streptomycin and the precipitated PrP(Sc) was recovered by centrifugation. The enrichment of PrP(Sc) by streptomycin sulfate precipitation was evaluated using Western blotting assay. The results showed streptomycin could bind to PK-treated PrP(Sc), forming high molecular masses, but not influence the glycosylated patterns on SDS-PAGE. Western blot assay revealed that the detective sensitivity of the streptomycin-precipitation PrP(Sc) was remarkably improved. As a sensitive, specific, rapid and flexible protocol for PrP(Sc), the protocol in this study has the potential utility, alone or combined with other techniques, for the detection of low level PrP(Sc) in the specimens from central nerve system, or from peripheral organs or body fluids.

Transcriptional repressive activity of mutated E2 protein of human papillomavirus 2 (HPV-2) variant / 病毒学报

Common warts are close associated with HPVs infection. In this study, we amplified and sequenced the LCR fragment and E2 gene of HPV-2 that infected the patient of extensive common wart with cutaneous horns, and we constructed the recombinant CAT-reporter plasmids pBLCAT-LCR containing HPV-2 prototype or variant LCR and mammalian expression plasmids pcDNA3. 1-E2 containing prototype or variant E2 ORF individually. The promoter activities of HPV-2 variant and the transcriptional repression activities of the mutated E2 protein were evaluated by transient transfection into HeLa cells. The results showed that there were several mutations in LCR and E2 gene of HPV-2 variant. Compared with the prototype, the viral early promoter activity of variant was significantly increased uder the control of LCR. Compared with the wild type E2 protein, the transcriptional repression activities of the mutated E2 protein was abolished partially. We speculate herein that increased promoter activities and decreased repression effect of the mutated E2 protein are linked, at least partially, with the clinical phenotypes of the uncommon huge common wart.

Expression of cytosolic PrP and analysis of its cytotoxic activities / 病毒学报

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.

PrP protein can bind to protein kinase CK2 both in native and recombinant forms in vitro / 病毒学报

To explore the possible molecular interaction between CK2 and PrP, the full length sequences of human CK2alpha and CK2beta genes were amplified with RT-PCR using the mRNA from cell line SH-SY5Y as the template, and then the fusion proteins HIS-CK2alpha and GST-HIS-CK2beta were expressed in E. coli. The interaction between CK2 and PrP was evaluated with immunoprecipitation and pull-down assays. The results demonstrated that recombinant PrP bound specifically with CK2alpha, but not with CK2beta. The native CK2 and PrP in the hamster brains interacted each other, forming protein complexes. The domain responsible for interacting with CK2alpha was located at the C-terminal segment of PrP (residues 90-231). This study proposed reliable experimental data for the molecular interaction between PrP and CK2alpha, both in recombinant and native categories. These results supply scientific clues for further assessing the potential biological significance of the interaction of PrP with CK2 and possible role of CK2 in the pathogenesis of prion diseases.

Interaction analysis between various PrP fusion proteins and the tubulin in vitro / 病毒学报

In order to further study the potential interaction between PrP protein and the tubulin and identify the binding region in PrP with tubulin, native tubulin was extracted from rabbit brian tissues, while various recombinant PrP proteins were expressed and purified. The possible molecular interaction between various PrP fusion proteins and tubulin was tested by pull-down and immunoprecipitation assays. Remarkable molecular interaction between the full length PrP and tubulin was observed by pull-down and immunoprecipitation assays. Subsequently, the binding regions within PrP with tubulin were firstly mapped in the aa 23 -- 91 region within N-terminus of PrP peptide. The studies of the association of PrP with tubulin may further provide insight into the unresolved mechanism of active transport of PrP protein in neurons and possible cellular pathways by which prion causes disease.

Expression of recombinant human doppel protein and analysis of its cytotoxic activities / 病毒学报

Doppel (Dpl) is a newly identified PrP-associated protein. In this study, specific primers for human PRND gene were designed based on the human PRND cDNA sequence encoding human Dpl protein reported in the GenBank. The full-length PRND gene sequence with 531 bp long was obtained from DNA of human peripheral leucocytes as the template by polymerase chain reaction (PCR). After verified by sequence analysis, the PCR product was inserted into a prokaryotic-expressing vector and then transformed into E. coli JM109. The recombinant human Doppel protein (rhDpl) was expressed as inclusion bodies after IPTG induction, with the yield of more than 60% of total bacterial proteins. The rhDpl protein was purified by Ni2+ affinity chromatography and cleaved by hydroxylamine. SDS-PAGE revealed the molecular weight of the purified rhDpl protein was about 15 kD. Trypan blue and MTT assays identified that rhDpl in vitro inhibited the growth of human neuroblastoma cell line SH-SY5Y at concentrations > or =50 microg/mL and human cervical cancer cell line HeLa at concentrations > or =100 microg/mL, showing remarkably dose-and time-dependant manners. Hoechst33342-staining of SH-SY5Y cells treated with rhDpl showed massive apoptosis under fluorescent microscope. These results indicate that Dpl protein possesses cytotoxic activity in vitro, with obvious tissue-specific characteristics. This study provides the foundation for further study of Dpl biological functions in vitro and in vivo.