Glycoproteins ; genetics ; metabolism ; Herpesviridae ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism

Baculoviridae ; genetics ; metabolism ; Phylogeny ; Viral Proteins ; chemistry ; classification ; genetics ; metabolism

Animals ; Herpesviridae ; genetics ; metabolism ; Humans ; Viral Proteins ; chemistry ; genetics ; metabolism

OBJECTIVETo investigate the biological role of auto-induced expression of hepatitis C virus (HCV) core protein (protein C) using a recombinant protein in an in vitro cell-based system.

METHODSThe PCR-amplified full-length HCV protein C gene (573 bp) was inserted into the pET28a prokaryotic expression vector. The recombinant plasmid was transformed into BL21(DE3)pLysS E. coli to achieve high-concentration expression of the recombinant C protein by auto-induction. The recombinant protein C was purified by Ni-NTA affinity chromatography, and tested in a protein binding assay for its ability to bind the HCV NS3 protein.

RESULTSThe transformed E. coli produced a large amount of recombinant protein C, as detected in the sonicated supernatant of the bacteria culture. The antigenic reactivity of the recombinant protein C was confirmed by western blotting. However, the recombinant protein C could not be purified by Ni-NTA affinity chromatography, but co-precipitated with the HCV NS3 protein.

CONCLUSIONSoluble recombinant protein C was successfully expressed by auto-induction, and shown to interact with the HCV NS3 protein, which provides a novel insight into the putative biological activity of this factor in HCV-related molecular processes. Future studies of this recombinant HCV protein C's crystal structure and antigenicity may provide further clues to its biological function(s) and potential for clinical applications.

Escherichia coli ; metabolism ; Genetic Vectors ; Hepacivirus ; Recombinant Proteins ; genetics ; metabolism ; Viral Core Proteins ; biosynthesis ; genetics ; metabolism ; Viral Nonstructural Proteins ; metabolism

Animals ; Genome, Viral ; Humans ; Viral Proteins ; genetics ; metabolism ; Yellow Fever ; virology ; Yellow fever virus ; genetics ; metabolism

According to previous studies of SARS-CoV (Severe acute respiratory syndrome coronavirus), a variety of novel accessory genes have been identified in SARS-CoV genome, which were interspersed the structural genes of SARS-CoV and considered to be unique to the SARS-CoV genome. The predicted unknown proteins (PUPs) encoded by the accessory genes might play important roles in the SARS-CoV infection. Three of those genes, called X4, X5 and ORF10, were synthesized and introduced into E. coli to induce expression. SDS-PAGE and Western blotting revealed that the three genes have been expressed in E. coli. The induction of SARS PUPs genes expression in different temperatures, induction times, IPTG concentrations and A values of E. coli cells were performed. The optimal induction condition of SARS-CoV PUPs genes was characterized according to the orthorgonal analysis. The ratio of recombinant proteins of PUPs to total proteins is as follows: X4, 20%; X5, 27.8%; ORF10, 68.5% under the optimum conditions.
Escherichia coli ; genetics ; metabolism ; Gene Expression Regulation, Viral ; Genes, Viral ; Genetic Vectors ; Genome, Viral ; Open Reading Frames ; Recombinant Proteins ; genetics ; metabolism ; SARS Virus ; genetics ; Temperature ; Time ; Viral Matrix Proteins ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism

Recently, the interactions between hepatitis C virus (HCV) genes and the host cell factors were the focus of this field. Cell factors in the different biochemical pathway were approved to be interfered when HCV infection. To make sure which HCV gene(s) was the major factor during the interaction process, ten eukaryotic expression plasmids containing different functional genes of HCV: Core, E1, E2, p7, NS2, NS3, NS4A, NS4B, NS5A and NS5B were transfected into the CHO-K1 cells respectively. Then ten stable cell lines expressing different HCV functional proteins were constructed under the selective pressure of G418. DNA and mRNA of the HCV genes were both detected by PCR and RT-PCR respectively in the corresponding stable cell lines, freezation and anabiosis would not lose the HCV genes. Besides, the El, E2 and NS5B proteins were detected by Western-blot which demonstrated that the HCV genes have formed stable expression in the host cells. The activity of UDP-glucose ceramide glucosyltransferase (UGCG) in the stable cell lines increased in different degree by TLC assay. For example, the activity of UGCG in CHO-K1-E2 and CHO-K1-p7 was doubled according to the control cells,and in CHO-K1-NS2 and CHO-K1-NS5A was about 1.6 times compared with the control cells. The establishment of the stable cell lines containing different single HCV gene will provide foundation for investigating the interactions between the virus and the host factors, and for the filtration of antiviral medicine.
Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Glucosyltransferases ; biosynthesis ; metabolism ; Hepacivirus ; genetics ; metabolism ; Transfection ; Viral Envelope Proteins ; biosynthesis ; genetics ; Viral Nonstructural Proteins ; biosynthesis ; genetics ; Viral Proteins ; biosynthesis ; genetics

OBJECTIVETo investigate biological functions of hepatitis C virus (HCV) non-structural protein 4A (NS4A).

METHODSYeast-two hybrid technique was performed to seek proteins in hepatocytes interacting with HCV NS4A. HCV NS4A bait plasmid was constructed by ligating the NS4A gene with carrier plasmid pGBKT7, then it was transformed into yeast AH109 (alpha type). The transformed yeast cells were amplified and mated with yeast cells Y187 (alpha type) containing liver cDNA library plasmid pACT2 in 2 x YPDA medium. Diploid yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-alpha-gal for selection two times. After extracting plasmid from blue colonies, plasmid DNA was transformed into competent E.coli and analyzed by DNA sequencing and bioinformatics methods.

RESULTSAmong twenty-two positive colonies there were eleven positive for metallothionein 2A, three for eukaryotic translation elongation factor 1 alpha 1, two for albumin, two for RNA binding motif protein 21, two for myomesin, one for cytochrome C oxidase II, and one for ATPase.

CONCLUSIONSGenes of HCV NS4A interacting proteins in hepatocytes were successfully cloned and the results pave the way for studying the biological functions of NS4A and associated proteins.

Carrier Proteins ; genetics ; Cloning, Molecular ; Hepacivirus ; genetics ; Hepatocytes ; metabolism ; Humans ; Two-Hybrid System Techniques ; Viral Nonstructural Proteins ; Viral Proteins ; genetics

OBJECTIVETo construct vectors expressing M2 and NA genes of H5N1 influenza virus.

METHODSBased on the human H5N1 avian influenza virus (A/Anhui/1/2005) isolated in china, M2 and NA genes were amplified by PCR. M2 or NA gene was subcloned into pStar vector to construct recombinant pStar-M2/, pStar-/M2, pStar-NA/and pStar-NA/. Furthermore, both of the M2 and NA genes were subcloned into pStar to construct two genes co-expressing recombinant pStar-M2/NA and pStar-NA/M2. Expression of the genes were detected by IFA after transfection of 293 cells with the recombinant plasmids.

RESULTSRecombinant plasmids were constructed and identified by restriction endonuclease digestion. Expression of the genes cloned into the recombinant plasmids was confirmed by IFA.

CONCLUSIONRecombinant plasmids expressing M2 and/or NA genes of H5N1 influenza virus were constructed, which provided basis for development of influenza DNA vaccine.

Cell Line ; Genetic Vectors ; genetics ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; metabolism ; Neuraminidase ; genetics ; metabolism ; Plasmids ; genetics ; Viral Matrix Proteins ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism

The newly emerged Middle East respiratory syndrome coronavirus (MERS-CoV) is a highly pathogenic respiratory virus with pathogenic mechanisms that may be driven by innate immune pathways. The goal of this study is to characterize the expression of the structural (S, E, M, N) and accessory (ORF 3, ORF 4a, ORF 4b, ORF 5) proteins of MERS-CoV and to determine whether any of these proteins acts as an interferon antagonist. Individual structural and accessory protein-coding plasmids with an N-terminal HA tag were constructed and transiently transfected into cells, and their native expression and subcellular localization were assessed using Wes tern blotting and indirect immunofluorescence. While ORF 4b demonstrated majorly nuclear localization, all of the other proteins demonstrated cytoplasmic localization. In addition, for the first time, our experiments revealed that the M, ORF 4a, ORF 4b, and ORF 5 proteins are potent interferon antagonists. Further examination revealed that the ORF 4a protein of MERS-CoV has the most potential to counteract the antiviral effects of IFN via the inhibition of both the interferon production (IFN-β promoter activity, IRF-3/7 and NF-κB activation) and ISRE promoter element signaling pathways. Together, our results provide new insights into the function and pathogenic role of the structural and accessory proteins of MERS-CoV.
Cell Line ; Coronavirus ; genetics ; pathogenicity ; Genes, Viral ; Humans ; Interferons ; antagonists & inhibitors ; Open Reading Frames ; Recombinant Proteins ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism ; Viral Regulatory and Accessory Proteins ; genetics ; metabolism ; Viral Structural Proteins ; genetics ; metabolism