Cell Cycle ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; analysis ; DNA Damage ; Dactinomycin ; pharmacology ; Humans ; Viral Nonstructural Proteins ; physiology

BACKGROUNDTo clarify the features of gene variation among epidemic strains of human rotavirus NSP4 in China.

METHODSSP4 genes from 27 epidemic strains of human rotavirus isolated in different area of China in recent years were amplified with RT-PCR, the resulted cDNAs were cloned and sequenced. The sequences of full length cDNAs were compared with 10 rotavirus NSP4 sequences available in the GenBank using the Clustal x 1.8 TreeView32 and DNA Star softwares. The G serotype of VP7 was analysed by PCR.

RESULTSThe homology of the amino acid among the 27 rotavirus strains isolated in China was 81.7%-99.4%. Based on the variation of amino acid sequence, the virus strains can be divided into two groups, represented by Wa and KUN with the homology of 92.0%-99.4% and 92.0%-98.9% within each group, respectively. The diversity between the two groups were 16.6%-21.0%. The Wa group could further be separated into three subgroups, according to the diversity between those strains and the characterization in the highly variable domain. The association between VP7 serotype and NSP4 genotype was not strong.

CONCLUSIONSThe NSP4 gene of human rotavirus epidemic strains in China can be divided into Wa and KUN two groups, Wa group is the main group and contains three subgroups possessing characteristic amino acid sites. Samples isolated in the same year but not in the same area shared higher homology.

Antigens, Viral ; Capsid Proteins ; genetics ; DNA, Complementary ; analysis ; DNA, Viral ; analysis ; Diarrhea ; virology ; Genetic Variation ; Genotype ; Glycoproteins ; genetics ; Humans ; Phylogeny ; Reverse Transcriptase Polymerase Chain Reaction ; Rotavirus ; genetics ; isolation & purification ; Sequence Analysis, DNA ; Toxins, Biological ; Viral Nonstructural Proteins ; genetics

OBJECTIVETo study the character of mutants originating from Japanese encephalitis viruses and the relationship between the characterization of mutant strains and E protein expression.

METHODSPersistent infection was established with standard strains of Japanese encephalitis viruse, known as parental viruse, in a human hepatoma cell line, KN73. Cells were subcultured weekly using trypsinization techniques. Cell-associated viruses of persistently infected cells were collected by a freeze and thaw method. Virus titers were examined by plaque method using baby hamster kidney (BHK) cells. Indirect immunofluorescence assays were used to examine E and NS3 protein antigens. Western blot analysis was used to test expression of E and NS3 proteins.

RESULTSIn the early phase (24 - 36 h) post-infection, virus titer in culture fluid from KN73 cells infected with parental viruses were 10(6) PFU/ml. They were 10(3 - 4) PFU/ml in the late phase (3 years) post-infection. The titer of cell-associated viruse was 10(2 - 3) PFU/ml. A virus super-infection assay found that virus titers in culture fluid from persistently infected KN73 cells acutely super- infected with parental viruses were much lower than that of culture fluids in acutely infected normal KN73 at the same phase. Indirect immunoflurescence assay revealed that the quantity of viral antigens in persistently infected KN73 cells was lower than that in acutely infected KN73 cells with parental viruses. Western blot analyses indicated that the molecular weights of E and NS3 proteins were 53 kD and 73 kD, respectively. Expression of NS3 protein in persistently infected KN73 cells was stable but expression of E protein was markedly suppressed.

CONCLUSIONSThe virulence and reproduction of viruses obtained from persistently infected KN73 cells, which have some features of DI viruses and were involved in persistent infection, was lower than that of parental viruses. These mutants may have be related to the decrease in E protein expression.

Carcinoma, Hepatocellular ; virology ; Defective Viruses ; physiology ; Encephalitis Virus, Japanese ; chemistry ; genetics ; physiology ; Humans ; Membrane Glycoproteins ; analysis ; Mutation ; RNA Helicases ; Serine Endopeptidases ; Tumor Cells, Cultured ; Viral Envelope Proteins ; analysis ; Viral Nonstructural Proteins ; analysis

BACKGROUNDTo investigate sequence of the complete E region of genotype 2a hepatitis C virus genome and to set up the basis for the further study on biological functions of envelope proteins of HCV.

METHODSTwo cDNA fragments of 770bp, 1,100bp long, from serum of a patients infected HCV, were amplified by reverse transcription nested polymerase chain reaction (RT-nPCR). After being digested with two restriction endonucleases, the two fragments were cloned into JM105 respectively, then sequenced.

RESULTSThe two corresponding nucleotide sequences were obtained and ligated. The complete nucleotide sequences of envelope region and corresponding deduced amino acid sequences were compared with those of HCV-1, HC-C2, HCV-BK, HC-J6 and HC-J8. The homology of nucleotide sequence of the isolated strains was 60.5%, 60.1%, 59.7%, 87.8% and 67.5% respectively; the amino acid sequence homology to the isolated strains was found to be 67?3%, 66.4%, 65.0%, 87.8%, 79.0%, respectively.

CONCLUSIONSThe results indicate that the isolated strain (HCV-JS) belongs to genotype 2a, but there is heterogeneity between HCV-JS and HC-J6 strain.

Amino Acid Sequence ; Cloning, Molecular ; DNA, Complementary ; genetics ; DNA, Viral ; genetics ; Genotype ; Hepacivirus ; genetics ; Hepatitis C ; virology ; Humans ; Molecular Sequence Data ; Sequence Analysis, DNA ; Sequence Homology, Nucleic Acid ; Viral Envelope Proteins ; genetics ; Viral Nonstructural Proteins ; genetics

OBJECTIVETo study the susceptibility of Aedes albopictus to dengue virus infection.

METHODSAedes albopictus from 15 collections in Guizhou province were challenged orally with dengue virus 1-4 types, respectively. The total RNA from mosquitos were extracted. The viral NS1 gene fragment was amplified with reverse transcriptase polymerase chain reaction (RT-PCR). Dengue virus in mosquitoes was isolated with C6/36 cells. Then the viral antigen was detected by indirect immunofluorescence assay (IFA). Antigen and nucleic acid of dengue virus from 15 geographic strains of Aedes albopictus orally infected with dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) were detected by IFA, RT-PCR and the virus was isolated with C6/36 cells, respectively.

RESULTSThe rates of Aedes albopictus orally infected with DEN-1, DEN-2, DEN-3 and DEN-4 were 12/15, 12/15, 8/15 and 13/15, respectively.

CONCLUSIONSDifferent geographic strains of Aedes albopitus in Guizhou were susceptible to dengue viruses.

Aedes ; cytology ; virology ; Animals ; Antigens, Viral ; analysis ; Cell Line ; China ; DNA, Viral ; analysis ; Dengue Virus ; genetics ; isolation & purification ; Disease Susceptibility ; Ecosystem ; Reverse Transcriptase Polymerase Chain Reaction ; Viral Nonstructural Proteins ; genetics

The non-structural 5B (NS5B) gene is the target region to identify hepatitis C virus (HCV) subtypes. However, it is not always possible to amplify this region because of inherently high sequence variability. Nucleotide sequences of the non-structural 5A (NS5A) and NS5B genes and its concordance were determined from patients infected with HCV genotype 1 (HCV-1). Among the 30 HCV-1 samples, 7 (23%) were identified as subtype 1a and 23 (77%) were identified as 1b by NS5A sequencing. Sequence analysis of the NS5B showed that 13 (43%) were identified as 1a and 17 (57%) were identified as 1b. Out of the 13 samples identified as 1a by NS5B, 6 (46%) were correctly identified by NS5A. Of the 17 samples identified as 1b by NS5B, 16 (94%) were correctly identified by NS5A. The presence of glutamic acid (E) or aspartic acid (D) at position 2225 in the NS5A differentiates 1a from 1b subtypes, respectively. This study showed that the NS5A sequencing can identify HCV-1a and 1b subtypes with predictive values of 86% and 70% of cases, respectively. The overall concordance with NS5B was 73%. NS5B sequence analysis remains to be the reference method to identify HCV-1 subtypes. NS5A sequencing may be used to complement NS5B sequencing in case the NS5B gene cannot be successfully amplified.

Human ; Male ; Female ; Aged ; Middle Aged ; Adult ; ; Aspartic Acid ; Genotype ; Glutamic Acid ; Hepacivirus ; Hepatitis C ; Nucleotides ; Sequence Analysis ; Viral Nonstructural Proteins

The NS1 gene of the H5N1 subtype avian influenza virus was amplified by RT-PCR, and the am-plified product was cloned into the eukaryotic expression vector pCMV-Myc, then it was transfected into A549 cells. After 48 h, the expression of NS1 was detected by Western blot. Fluorescence and electron microscopy and flow cytometry showed that the NS1 gene of H5N1 avian influenza virus could induce apop-tosis in human pulmonary carcinoma cell line A549.
Annexin A5 ; analysis ; Apoptosis ; Cell Line, Tumor ; Cloning, Molecular ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; pathogenicity ; Lung Neoplasms ; pathology ; Viral Nonstructural Proteins ; genetics ; physiology

Rotavirus (RV)-infected piglets are presumed to be latent sources of heterologous RV infection in humans and other animals. In RVs, non-structural protein 4 (NSP4) is the major virulence factor with pleiotropic properties. In this study, we analyzed the nsp4 gene from porcine RVs isolated from diarrheic and non-diarrheic cases at different levels of protein folding to explore correlations to diarrhea-inducing capabilities and evolution of nsp4 in the porcine population. Full-length nsp4 genes were amplified, cloned, sequenced, and then analyzed for antigenic epitopes, RotaC classification, homology, genetic relationship, modeling of NSP4 protein, and prediction of post-translational modification. RV presence was observed in both diarrheic and non-diarrheic piglets. All nsp4 genes possessed the E1 genotype. Comparison of primary, secondary, and tertiary structure and the prediction of post-translational modifications of NSP4 from diarrheic and non-diarrheic piglets revealed no apparent differences. Sequence analysis indicated that nsp4 genes have a multi-phyletic evolutionary origin and exhibit species independent genetic diversity. The results emphasize the evolution of the E9 nsp4 genotype from the E1 genotype and suggest that the diarrhea-inducing capability of porcine RVs may not be exclusively linked to its enterotoxin gene.
Animals ; Classification ; Clone Cells ; Enterotoxins ; Epitopes ; Genetic Variation ; Genotype ; Humans ; Protein Folding ; Protein Processing, Post-Translational ; Rotavirus ; Sequence Analysis ; Viral Nonstructural Proteins ; Virulence

OBJECTIVE: To investigate the proteome of hepatocyte transformation by hepatitis C virus (HCV) nonstructural protein 3 (NS3). METHODS: Human hepatocyte line QSG7701 stably expressing HCV NS3 C-terminal deleted protein was constructed, which was named pRcHCNS3/QSG. Two-dimensional electrophoresis (2-DE) was used to separate the total protein of pRcHCNS3/QSG and pRcCMV transfected cells (pRcCMV/QSG) respectively. Differentially expressed protein spots were identified by mass spectrometry. Western blot confirmed the differentially expressed proteins. RESULTS: 2-DE profiles with high resolution and reproducibility were obtained. The average spots of pRcHCNS3/QSG and pRcCMV/QSG were (1183+/-77) and (1095+/-82) respectively, and (920+/-60) spots were matched. Twenty-one differentially expressed protein spots were chosen randomly and 15 were identified by mass spectrometry. Some proteins such as Ras, P38 and HD53 which were involved in signal transduction were increased in pRcHCNS3/QSG cells. Western blot also showed strong expression of phosphorylated P44/42 and P38 in pRcHCNS3/QSG cells. Other differentially expressed proteins were related to cell cycle regulation, immunoreaction, tumor invasion and metastasis, and liver metabolizability. CONCLUSION HCV NS3 might be involved in cell malignant transformation through affecting protein expression and signal transduction such as MAPK cascade. Further study on the signal transductions and their relationship would not only be helpful to explore the mechanism of HCV related HCC, but also provide a new idea for the molecular treatment of HCC.
Cell Line ; Cell Transformation, Neoplastic ; Electrophoresis, Gel, Two-Dimensional ; methods ; Hepatocytes ; metabolism ; pathology ; Humans ; Mass Spectrometry ; methods ; Proteome ; analysis ; Proteomics ; methods ; Transfection ; Viral Nonstructural Proteins ; biosynthesis ; genetics

OBJECTIVE: To screen differentially expressed genes and gene pathways in L02 cell line stably expressing hepatitis C virus (HCV) Ib type nonstructural protein 4B (NS4B) mediated by lentiviral system, and to provide a basis for further research of molecular biological mechanism of NS4B gene in chronic hepatitis C and hepatocarcinogenesis. METHODS: NS4B stably overexpressed L02 cell line and negative control stable L02 cell line, designated as L02-NS4B and L02-mkate2 respectively, were resurrected and amplified in vitro. The differentially expressed genes between L02-NS4B and L02-mkate2 were determined by gene expression microarray from Human Gene 1.0ST. The significant pathways of the differential genes were selected by the Fisher's exact test and χ2 test according to kyoto encyclopedia of genes and genomes (KEGG) database. The differential expression levels of 5 selected genes including protein kinase C delta binding protein (PRKCDBP), tumor protein p53 (TP53), v-akt murine thymoma viral oncogene homolog 1 (AKT1), baculoviral IAP repeat containing 3 (BIRC3) and B-cell lymphoma 2-like1 (BCL2L1) from cDNA microarray data were further verified by real-time quantitative polymerase chain reaction (real-time QPCR). RESULTS: Between L02-NS4B and L02-mkate2, the genes with flurescence intensity ratio >1.2 or <0.8 were considered as differentially expressed genes. A total of 2 682 differentially expressed genes in the known 28 869 human genes were detected in L02-NS4B, 1 446 genes were upregulated and 1 236 genes were downregulated. A total of 41 involved pathways of up-regulated differential genes were identified by KEGG database, mainly including apoptosis, extracellular matrix receptor interaction, cell cycle, pathways in cancer and Toll-like receptor signaling pathway; and 20 involved pathways of down-regulated differential genes were identified, mainly including pathways in cancer, Wnt signaling pathway and cell cycle pathway. Of the 5 upregulated genes selected from cDNA microarray data, 3 genes showed the same differential expression pattern by real-time QPCR as that shown in cDNA microarray data, namely AKT1, BIRC3 and BCL2L1. The confirmation rate of real-time QPCR was 60%. CONCLUSION HCVNS4B can up-regulate or down-regulate the expression of many genes in L02 cells, thus affecting multiple signaling pathways relevant to cell apoptosis, cell cycle and carcinogenesis.
Cell Cycle ; Cell Line ; Gene Expression Profiling ; Hepacivirus ; genetics ; Humans ; Oligonucleotide Array Sequence Analysis ; Real-Time Polymerase Chain Reaction ; Signal Transduction ; Transcriptional Activation ; Viral Nonstructural Proteins ; genetics