Kunjin virus replicon--a novel viral vector / 生物工程学报

Viral replicon is a kind of self-replicating viral RNA sourced from viral genome, which contains viral non-structural genes that are critical for viral genome replication with structural proteins deleted or replaced by foreign genes. Kunjin virus is a member of the Flavivirida family, Flavivirus genus, and Kunjin virus replicon is the first and the clearly defined flavivirus replicon. Kunjun virus replicon has been regarded as an excellent viral vector on account of its high expression, lower cytotoxicity and genetic stability. These unique characteristics of kunjin virus replicons make them suitable for the study of viral genome replication, recombinant proteins production, vaccine development and gene therapy. In this article, recent progress in the development, properties and applications of kunjin virus replicon system was briefly reviewed.

Preparation and identification of dengue virus with deletion mutation of capsid protein / 南方医科大学学报

<p><b>OBJECTIVE</b>To generate rescued viruses with deletion mutation of capsid protein from dengue virus type 2 isolated in China (DEN2-43).</p><p><b>METHODS</b>On the basis of infectious full-length cDNA clone pD212 of DEN2-43 strain virus, the deletion mutants were constructed by fusion PCR, from which the rescued viruses with deletion mutation of capsid protein were generated by transcription in vitro and electroporation.</p><p><b>RESULT AND CONCLUSION</b>Sequence analysis demonstrated that the deletion mutations had been successfully inserted into the rescued viruses obtained. These mutant viruses may hold the key for elucidating the effects of deletion mutation of capsid protein on the biological characteristics of dengue virus.</p>

Ultrastructural characteristics of SARS associated virus in infected cells / 中华病理学杂志

<p><b>OBJECTIVE</b>Electron microscopical study of infected cells to identify the pathogenic agent of SARS.</p><p><b>METHODS</b>Vero E6 cells infected with lung autopsy samples or nasopharyngeal swabs from SARS patients of Beijing and Guangzhou were inoculated. The supernatant and cultured cells exhibiting identifiable cytopathic effect (CPE) were prepared for electron microscopic study.</p><p><b>RESULTS</b>Examination of CPE cells on thin-section revealed characteristic coronavirus particles within the cisternae of endoplasmic reticulum, Golgi apparatus, vesicles and extracellular space. They were mainly spherical or oval in shape, annular or dense, about 80 nm in diameter. Negative-stain electron microscopy identified coronavirus particles in culture supernatant, 80 - 120 nm in diameter, with club-shaped surface projections. Elongated, rod-, kidney- or other irregular shaped virons with the size of 100 - 200 nm by 60 - 90 nm were also found in the cultured cells infected with the lung samples from the Guangdong patients. Infectious virons entered cells by endocytosis or membrane fusion and released through a budding process.</p><p><b>CONCLUSION</b>These data indicate a novel coronavirus as the causative agent of SARS. Most viral particles showed typical characteristics of coronavirus. The potential role of special shape viruses is expected to be further investigated.</p>

A genome sequence of novel SARS-CoV isolates: the genotype, GD-Ins29, leads to a hypothesis of viral transmission in South China / 基因组蛋白质组与生物信息学报·英文版

We report a complete genomic sequence of rare isolates (minor genotype) of the SARS-CoV from SARS patients in Guangdong, China, where the first few cases emerged. The most striking discovery from the isolate is an extra 29-nucleotide sequence located at the nucleotide positions between 27,863 and 27,864 (referred to the complete sequence of BJ01) within an overlapped region composed of BGI-PUP5 (BGI-postulated uncharacterized protein 5) and BGI-PUP6 upstream of the N (nucleocapsid) protein. The discovery of this minor genotype, GD-Ins29, suggests a significant genetic event and differentiates it from the previously reported genotype, the dominant form among all sequenced SARS-CoV isolates. A 17-nt segment of this extra sequence is identical to a segment of the same size in two human mRNA sequences that may interfere with viral replication and transcription in the cytosol of the infected cells. It provides a new avenue for the exploration of the virus-host interaction in viral evolution, host pathogenesis, and vaccine development.

Complete genome sequences of the SARS-CoV: the BJ Group (Isolates BJ01-BJ04) / 基因组蛋白质组与生物信息学报·英文版

Beijing has been one of the epicenters attacked most severely by the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) since the first patient was diagnosed in one of the city's hospitals. We now report complete genome sequences of the BJ Group, including four isolates (Isolates BJ01, BJ02, BJ03, and BJ04) of the SARS-CoV. It is remarkable that all members of the BJ Group share a common haplotype, consisting of seven loci that differentiate the group from other isolates published to date. Among 42 substitutions uniquely identified from the BJ group, 32 are non-synonymous changes at the amino acid level. Rooted phylogenetic trees, proposed on the basis of haplotypes and other sequence variations of SARS-CoV isolates from Canada, USA, Singapore, and China, gave rise to different paradigms but positioned the BJ Group, together with the newly discovered GD01 (GD-Ins29) in the same clade, followed by the H-U Group (from Hong Kong to USA) and the H-T Group (from Hong Kong to Toronto), leaving the SP Group (Singapore) more distant. This result appears to suggest a possible transmission path from Guangdong to Beijing/Hong Kong, then to other countries and regions.

Study of interaction between NS3 serine protease of HCV and wild type P53 / 军事医学科学院院刊

Objective:To investigate the molecular interaction between non-structural protein 3 serine protease of hepatitis C virus(HCV)and wild type P53,and to lay the basis for elucidating the mechanism of oncogenesis of hepatocellular carcinoma(HCC)after infection of HCV.Methods:The recombinant plasmids,pGAD424-NS3,pGAD424-NS315aa- and pGAD424-NS330aa-,were constructed and the interaction between NS3 serine protease and its cofactor NS4A,the interaction between wild type P53 and NS3 serine protease and its N-truncated mutants were dectected qualitatively and quantitatively in yeast two-hybrid system.Results:The results indicated that interaction existed not only between full-length NS3 serine protease and P53,but also between N-truncated mutants of NS3 serine protease and P53.Furthermore,the difference between enzyme activity unit(IU)of β-gal induced by these interactions was not significant(P>0.05).Conclusions:NS3 serine protease of hepatitis C virus and its N-truncated mutants can interact with wild type P53,and the region of NS3 serine protease involved in the interaction may be located in its C-terminal,but not in its N-terminal.

Cloning and expression of dengue 2 virus NS1 gene in eukaryotic cells / 军事医学科学院院刊

Objective：To investigate the correct expression of dengue 2 virus 43 strain NS1 gene in transfected BHK-21 cell. Methods：The D2-43 DNA fragment coding for signal peptide plus NS1 protein was cloned between KpnⅠ site and EcoR Ⅰ site of expression plamid pcDNA3.1. The obtained recombinant vector pcDNA-NS1 was transfected into BHK-21 cells with electroporation technique. After selection by G418, resistant clones were screened by RT-PCR and Western blotting test. Results：The RT-PCR results of four in five randomly selected cell clones were positive. Western blotting test showed that NS1 gene could be expressed in BHK-21 cells. Conclusions：NS1 protein was capable of being expressed and appropriately processed in pcDNA-NS1 transfected BHK-21 cells. The present results suggest the feasibility of NS1-based DNA immunization.