• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.463-469
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• 2002

Rotaviruses are the world-wide leading causative agents of severe dehydrating gastroenteritis in young children and animals. The outer capsid glycoprotein VP7 and inner capsid glycoprotein VP6 of rotaviruses are highly antigenic and immunogenic. An SFV-based expression system has recently emerged as a useful tool for heterologous protein production in mammalian cells, exhibiting a much more efficient performance compared to other gene expression systems. Accordingly, the current study adopted an SFV-based expression system to express the VP7 of a group A human rotavirus from a Korean isolate, and the VP6 of a group B bovine rotavirus from a Korean isolate, in mammalian cells. The genes of the VP6 and VP7 were inserted into the SFV expression vector pSFV-1. The RNA was transcribed in vitro from pSFV-VP6 and pSFV-VP7 using SP6 polymerase. Each RNA was then electroporated into BHK-21 cells along with pSFV-helper RNA containing the structural protein gene without the packaging signal. The expression of VP6 and VP7 in the cytoplasm was then detected by immunocytochemistry. The recombinant virus was harvested by ultracentrifugation and examined under electron microscopy. After infecting BHK-21 cells with the defective viruses, the expressed proteins were separated by SDS-PAGE and analyzed by a Western blot. The results indicate that an SFV-based expression system fur the VP6 and VP7 of rotaviruses is an efficient tool for developing a diagnostic kit and/or preventive vaccine.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.563-568
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• 2002

Stably transformed Drosophila melanogaster 52 cells producing recombinant VP7 were obtained, and recombinant VP7 expression was confirmed by Western blot analysis. The molecular weight of recombinant VP7 expressed in 52 cells was approximately 35.5 kDa, and 75% of the total VP7 produced was present in the medium. Recombinant VP7 contained N-linked glycosylated oligosaccharides. Aprotinin, leupeptin, and polyvinylpyrrolidone did not have any noticeable effect on recombinant VP7 production; however, DMSO and sodium butyrate increased its production by 120% and 60%, respectively.

• Journal of Life Science
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• v.28 no.4
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• pp.478-482
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• 2018

Human rotavirus is a causative agent of acute diarrhea among children. The artificial gene encoding the truncated $VP8^*$ protein of human rotavirus A (serotype 1 strain WA) was synthesized according to the Escherichia coli codon preference. The synthetic $VP8^*$ gene also possessed the NdeI and HindIII restriction sites for the convenient in-frame cloning for translation and a 6-histidine tag at C-terminus for Ni+ affinity purification. Molecular weight of the truncated $VP8^*$ protein deduced from the nucleotide sequences of the artificial gene was a 19.7-kDa. This synthetic $VP8^*$ DNA fragment was inserted into the pT7-7 expression vector and transformed into E. coli BL21 (DE3). Transformants harboring the synthetic gene encoding the $VP8^*$ protein was induced by supplement of a final concentration of 0.05 mM ITPG at $20^{\circ}C$. Protein crude extract from the E. coli transformants was subjected to Western blotting with the mouse anti-rotavirus capsid antibody, showing ~20-kDa $VP8^*$ protein band. The truncated $VP8^*$ protein band was also observed by Western blotting using the rabbit polyclonal antibody serum made against the truncated $VP8^*$ protein. This study suggested that the synthetic gene could be used as an easy way to produce the antigenic vaccine candidate for control of virus-associated diseases or to develop antibodies for diagnostic purpose.

• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.369-377
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• 1998

Rotavirus is a major cause of severe gastroenteritis in young children and animals throughout the world. The VP7 of rotavirus is thought to induce the synthesis of neutralizing antibodies and to be responsible for determining viral serotypes. The cDNA coding for the VP7 capsid protein of human rotavirus, obtained from Korean patients (HRV-Y14), was cloned and its nucleotide sequence was determined. Comparative analysis of the nucleotide sequences between VP7 of Y14 and that of other foreign isolates showed $92.7~95.2\%$ homology to G1 serotypes (RV-4, KU, K8, WA), $74.2\%$ homolgy to G2 serotype HU-5, $76.4\%$ homology to G3 serotype SA-11, and $77.6\%$ homology to G4 serotype A01321. These data suggest that HRV-Y14 can be classified as a G1 serotype. cDNA coding for VP7 of HRV-YI4 was subcloned into the baculovirus vector and the VP7 glycoprotein was expressed in insect cells. The expressed proteins in Sf9 cell extract and tissue culture fluid were separated on SDS-PAGE, and Western blot analysis with monoclonal antibody raised against the synthetic peptide containing 21 amino acids within the VP7 conserved region was performed. The molecular weight of recombinant VP7 was estimated to be 36 kDa which is about the same size as the native VP7. Addition of tunicamycin in the culture media caused a reduction of the molecular weight of the recombinant VP7 indicating that the expressed protein was glycosylated.