Browsing by Subject "hepatitis B virus"

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    Fluorescent protein tagged hepatitis B virus capsid protein with long glycine-serine linker that supports nucleocapsid formation
    (Elsevier, 2018-05) Chen, Jiang-Yan; Gan, Chun-yang; Cai, Xue-fei; Zhang, Wen-lu; Long, Quan-xin; Wei, Xia-fei; Hu, Yuan; Tang, Ni; Chen, Juan; Guo, Haito; Huang, Ai-long; Hu, Jie-li; Microbiology and Immunology, School of Medicine
    Fusion core proteins of Hepatitis B virus can be used to study core protein functions or capsid trafficking. A problem in constructing fusion core proteins is functional impairment of the individual domains in these fusion proteins, might due to structural interference. We reported a method to construct fusion proteins of Hepatitis B virus core protein (HBc) in which the functions of fused domains were partially kept. This method follows two principles: (1) fuse heterogeneous proteins at the N terminus of HBc; (2) use long Glycine-serine linkers between the two domains. Using EGFP and RFP as examples, we showed that long flexible G4S linkers can effectively separate the two domains in function. Among these fusion proteins constructed, GFP-G4S186-HBc and RFP-G4S47-HBc showed the best efficiency in rescuing the replication of an HBV replicon deficient in the core protein expression, though both of the two fusion proteins failed to support the formation of the relaxed circular DNA. These fluorescent protein-tagged HBcs might help study related to HBc or capsids tracking in cells.
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    Functional association of cellular microtubules with viral capsid assembly supports efficient hepatitis B virus replication
    (Nature Publishing group, 2017-09-06) Iwamoto, Masashi; Cai, Dawei; Sugiyama, Masaya; Suzuki, Ryosuke; Aizaki, Hideki; Ryo, Akihide; Ohtani, Naoko; Tanaka, Yasuhito; Mizokami, Masashi; Wakita, Takaji; Guo, Haitao; Watashi, Koichi; Microbiology and Immunology, School of Medicine
    Viruses exploit host factors and environment for their efficient replication. The virus-host interaction mechanisms for achieving an optimal hepatitis B virus (HBV) replication have been largely unknown. Here, a single cell cloning revealed that HepAD38 cells, a widely-used HBV-inducible cell line, contain cell clones with diverse permissiveness to HBV replication. The HBV permissiveness was impaired upon treatment with microtubule inhibitor nocodazole, which was identified as an HBV replication inhibitor from a pharmacological screening. In the microtubule-disrupted cells, the efficiency of HBV capsid assembly was remarkably decreased without significant change in pre-assembly process. We further found that HBV core interacted with tubulin and co-localized with microtubule-like fibriforms, but this association was abrogated upon microtubule-disassembly agents, resulting in attenuation of capsid formation. Our data thus suggest a significant role of microtubules in the efficient capsid formation during HBV replication. In line with this, a highly HBV permissive cell clone of HepAD38 cells showed a prominent association of core-microtubule and thus a high capacity to support the capsid formation. These findings provide a new aspect of virus-cell interaction for rendering efficient HBV replication.
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    A virus-like particle of the hepatitis B virus preS antigen elicits robust neutralizing antibodies and T cell responses in mice
    (Elsevier, 2018-01) Cai, Xiaodan; Zheng, Weihao; Pan, Shaokun; Zhang, Shengyuan; Xie, Youhua; Guo, Haitao; Wang, Guoxin; Li, Zigang; Luo, Ming; Microbiology and Immunology, School of Medicine
    The preS antigen of hepatitis B virus (HBV) corresponds to the N-terminal polypeptide in the large (L) antigen in addition to the small (S) antigen. The virus-like particle (VLP) of the S antigen is widely used as a vaccine to protect the population from HBV infection. The presence of the S antigen and its antibodies in patient blood has been used as markers to monitor hepatitis B. However, there is very limited knowledge about the preS antigen. We generated a preS VLP that is formed by a chimeric protein between preS and hemagglutinin (HA), and the matrix protein M1 of influenza virus. The HBV preS antigen is displayed on the surface of preS VLP. Asn112 and Ser98 of preS in VLP were found to be glycosylated and O-glycosylation of Ser98 has not been reported previously. The preS VLP shows a significantly higher immunogenicity than recombinant preS, eliciting robust anti-preS neutralizing antibodies. In addition, preS VLP is also capable of stimulating preS-specific CD8+ and CD4+ T cell responses in Balb/c mice and HBV transgenic mice. Furthermore, preS VLP immunization provided protection against hydrodynamic transfection of HBV DNA in mice. The data clearly suggest that this novel preS VLP could elicit robust immune responses to the HBV antigen, and can be potentially developed into prophylactic and therapeutic vaccines.